Methods of polymer doping and acid triggered side chain cleavage and polymers therefrom

Abstract

The subject matter described herein is directed to methods of polymer doping and acid triggered side chain cleavage and polymers and copolymers prepared from these methods, and devices comprising the polymers and / or copolymers.

Description

[0001] METHODS OF POLYMER DOPING AND ACID TRIGGERED SIDE CHAIN

[0002] CLEAVAGE AND POLYMERS THEREFROM

[0003] STATEMENT OF GOVERNMENT SUPPORT

[0004] [1] This invention was made with government support under Grant No. N00014-23-1- 2001 awarded by Department of Defense and Grant No. DMR2210586 awarded byNational Science Foundation. The government has certain rights in the invention.

[0005] FIELD

[0006] [2] The subject matter described herein is directed to methods of polymer doping and acid triggered side chain cleavage and polymers prepared from these methods.

[0007] BACKGROUND

[0008] [3] Molecular doping is crucial to increasing charge carrier density and provide tunable conductivity to conjugated polymers (CPs). Although, there are newer methodologies for doping highly crystalline or polar side chain bearing polymers, new strategies to achieve high yet stable conductivity of doped CPs have stagnated in comparison.

[0009] [4] What is therefore needed is a new paradigm for preparing polymers that provide the desired characteristics, in particular stability and conductivity. The subject matter described herein addresses these needs and more.

[0010] BRIEF SUMMARY

[0011] [5] In certain embodiments, the subject matter described herein is directed to methods of preparing a doped polymer or copolymer, comprising: contacting a precursor polymer or copolymer with an acid dopant solution, wherein, the acid dopant solution comprises a dopant and an acid, and the precursor polymer or copolymer is a cleavable side chain-based polymer or copolymer, wherein, one or more side chains on the precursor polymer or copolymer are cleaved by the acid and the precursor polymer or copolymer is doped with the dopant to form the doped polymer or copolymer.

[0012] [6] In certain embodiments, the doped polymer or copolymer has an increased conductivity compared to that of the corresponding precursor polymer or copolymer.

[0013] [7] In certain embodiments, acid dopant solution comprises F4TCNQ and TfOH.

[0014] [8] In certain embodiments, the precursor polymer comprises wherein,

[0015] M is a monomer or block in the backbone of the polymer;

[0016] A is a cleavable side chain; and, n is an integer from 1 to 1,000.

[0017] [9] In certain embodiments, the cleavable side chain based conjugated polymer comprises

[0018]

[0010] In certain embodiments, the cleavable side chain based conjugated polymer comprises

[0019]

[0011] In certain embodiments, the subject matter described herein is directed to a doped polymer or copolymer comprising wherein,

[0020] M is a monomer or block in the backbone of the polymer; and. n is an integer from 1 to 1,000, wherein, the amount of dopant present in the doped polymer or copolymer is from about 0.1% to about 99% (vs. amount of the repeating unit in a given polymer).

[0021]

[0012] In certain embodiments, the doped polymer or copolymer has a conductivity no less than 1 S / cm.

[0022]

[0013] In certain embodiments, the doped polymer or copolymer comprises

[0023]

[0014] In certain embodiments, the doped polymer or copolymer comprises

[0024]

[0015] In certain embodiments, the doped polymer or copolymer comprises

[0025]

[0016] In certain embodiments, the doped polymer or copolymer comprises

[0026]

[0017] In certain embodiments, the doped polymer or copolymer is in the form of a film.

[0027]

[0018] In certain embodiments, the subject matter described herein is directed to a conductor material comprising a doped polymer or copolymer as described herein for use in optoelectronic devices such as OLED (organic light emitting diode), OFET (organic field effect transistors), OPV (organic photovoltaics), and OECT (organic electrochemical transistors).

[0028]

[0019] In certain embodiments, the subject matter described herein is directed to a semiconductor device comprising the doped polymer or copolymer as described herein.

[0029]

[0020] Other embodiments are also described.

[0030] BRIEF DESCRIPTION OF THE FIGURES

[0031]

[0021] Figure 1 depicts HOMO energy levels for polymers vs F4TCNQ LUMO energy level (all estimated by CV).

[0032]

[0022] Figure 2A-D depict Conductivity vs. different cleavage and doping method combinations. All Dip conditions indicate dipping in a solution of 3.6 mM F4TCNQ in acetonitrile for 30 min; 200 °C denotes that annealing was done for 30 min and TfOH indicates dipping in a solution of 22.6 mM TfOH in acetonitrile for 30 min. “+” indicates sequence of methods. “@65 °C’' indicates doping solution at 65 °C for 30 min.

[0033]

[0023] Figure 3A-C depict (a) Conductivity of different polymers at different doping conditions, (b) Carrier concentration and mobility from Hall measurement of CSCPs. (c) Carrier concentration and mobility7from Hall measurement of POET-T2 vs. doping condition.

[0034]

[0024] Figure 4A-D depict (a) UPS spectral at Fermi edge and (b) cutoff edge for POET- T2 (or COOH) films after applying different doping methods. Stability measurement for conductivity in inert glovebox at (c) 25 °C and (d) 100 °C for ACTVIE doped POET-T2 (COOH) and F4TCNQ doped PBTTT.

[0035]

[0025] Figure 5 shows data for how an exemplary process described herein prepares desirable polymers that have unexpectedly high conductivity7.

[0036]

[0026] Figure 6 depicts data for conductivity testing of ACTVIE condition substituting stronger dopant FeCh with and with TfOH (right panel), original ACTVIE condition in main text with F4TCNQ and TfOH (middle panel) and ACTVIE condition with stronger acid trifluoromethylsulfonimide (Tf2NH) (right panel). Concentrations are consistent at 22.6 mM for acid and 3.6 mM for Dopant.

[0037]

[0027] Figure 7A-C depict Sulfur 2p XPS spectra deconvolution of differently doped POET-T2.(a) Dip doping with 22.6 pM TfOH, (b) dip doping with 3.6 mM F4TCNQ, (c) dip doping with combined 22.6 mM TfOH with 3.6 mM F4TCNQ. Each experiment was done for 30 min in acetonitrile. S(ulfur) 2p A fit represents polymer sulfur signal, S 2p B fit represents TfOH sulfur signal and S 2p C fit represents polaron sulfur signal.

[0038]

[0028] Figure 8A-D depict transconductance plots as a function of gate voltages with various device geometries. (a,b) POET-T2 before cleavage, (c,d) POET-T2 after cleavage. Drain voltage was maintained to be -0.5 V for all measurements. The channel width-to-length ratio varied from 10 to 30 across the devices.

[0039]

[0029] Figure 9A-K depict Mixed ionic-electronic conduction characteristics of all-solid- state OECTs. a, Schematic illustration, and optical microscope image of the device architecture. Transfer characteristics of OECTs with (b) pristine and (c) side-chain- cleaved POET-T2 films, using [EMIM][TFSI]-based gel electrolyte, d, Geometry - normalized transconductance (gm, norm) and subthreshold swing (SS) of POET-T2 OECTs. Output characteristics of (e) pristine and (f) side-chain-cleaved POET-T2 OECTs. g, Transconductance (gm) and (h) rise time (rr) plots as a function of device geometry, controlled via film thickness and channel length, i, Long-term on / off stability’ of POET- T2 OECTs under repeated gate pulses (0 / -0.6 V, 0. 125 Hz) with a constant drain voltage of -0.5 V. j, Box plots of gm, norm for various polymers evaluated from at least six independent devices (dashed lines are guides to the eye), k. Comparison of on / off current ratio and gC* product of POET-T2 with previously reported OECTs operated at |Fb| < 0.5 V.44-61Intrinsic material properties were considered; processing-based studies (e.g., mechanical stretching) were excluded.

[0040]

[0030] Figure 10A-D show transient responses of POET-T2-based OECTs before and after side-chain cleavage, measured across different device geometries. (a,b) POET-T2 before cleavage, (c,d) POET-T2 after cleavage. Gate pulses of -1 V were applied while maintaining a constant drain voltage of -0.5 V. The channel width-to-length ratio varied from 10 to 30 across the devices.

[0041]

[0031] Figure 11 A-H show: a-d, Transfer characteristics and (e-h) output characteristics of organic electrochemical transistors (OECTs) for various polymers using [EMIM][TFSI]-based gel electrolyte. (a,e) P3HT, (b,f) p(gs2T-T), (c,g) co-polymer before cleavage, (d,h) co-polymer after cleavage. Device geometric factors are provided at the inset of the graphs.

[0042]

[0032] Figure 12A-G show: a-f, Transfer characteristics of OECTs based on various polymers, measured using [EMIM][OTf] -based gel electrolyte, a, P3HT, (b) p(gs2T-T), (c) POET-T2 before cleavage, (d) POET-T2 after cleavage, (e) co-polymer before cleavage. (1) co-polymer after cleavage. Device geometric factors are provided at the inset of the graphs, (g) Normalized transconductance of each polymer, evaluated from at least six distinct devices.

[0043] DETAILED DESCRIPTION

[0044]

[0033] Disclosed herein are efficient methods for doping that is generally applicable to precursor polymers and copolymers, such as cleavable side chain based conjugated polymers (CSCPs). Such doped polymers have improved conductivities, for example in excess of 350 S / cm and much improved stability.

[0045]

[0034] Molecular doping is crucial to increasing charge carrier density (n) and provide tunable conductivity (o) to conjugated polymers (CPs).1-2Although recent works have made breakthroughs in methodology to dope highly crystalline or polar side chain bearing poly mers.3 9new strategies to achieve high yet stable conductivity of doped CPs have stagnated in comparison. As described herein, the methods utilize cleavable side chain based conjugated polymers (CSCPs) for molecular doping and achieve multiple orders of magnitude range in improved conductivity. The methods simultaneously cleave and dope, a so-called '‘cleavage with doping" methodology, which is shown to be superior to common doping methods.

[0046]

[0035] CSCPs are in particular advantageous because they eliminate the insulating side chains in processed CP fdms. The resulting shorter lamellar spacing can induce less backbone disorder and shorter K-TI stacking, beneficial for higher carrier mobility ( / / );1912the concomitant volume reduction also leads to higher n.13,14Furthermore, the elimination of soft alkyl chains increase the glass transition of the CP, and remnant carboxylic acids can mitigate destructive oxidation of polymers,15 19improving stability of the processed CP film. These polymers include the first reported CSCP - regiorandom P3MOCT,20a regioregular RP-T5O,10and other CSCPs, aptly named PIET-T2 and POET- T2. The two latter polymers incorporate what is show n herein to be a twisted inw ard facing biester thiophene motif (IET) or a planar outward facing biester thiophene motif (GET), respectively. Such orientations (twisted vs. planar) have been determined previously in single crystal analysis of similar linear-ester thiophene dimers.22 24Certain non-limiting polymers described herein are represented in Scheme 1. P3M0CT; Spacer Unit

[0047] Scheme 1.

[0048]

[0036] The presently disclosed subject matter will now be described more fully hereinafter. However, many modifications and other embodiments of the presently disclosed subject matter set forth herein will come to mind to one skilled in the art to which the presently disclosed subject matter pertains having the benefit of the teachings presented in the foregoing descriptions. Therefore, it is to be understood that the presently disclosed subject matter is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. In other words, the subject matter described herein covers all alternatives, modifications, and equivalents. In the event that one or more of the incorporated literature, patents, and similar materials differs from or contradicts this application, including but not limited to defined terms, term usage, described techniques, or the like, this application controls. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in this field. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In the drawings, the relative sizes of regions or features may be exaggerated for clarity. This subject matter may, however, be embodied in many different forms and should not be construed as limited to the aspects set forth herein; rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the subj ect matter to those skilled in the art.

[0049] I. Definitions

[0050]

[0037] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the present application and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. The terminology used in the description of the subject matter herein is for the purpose of describing particular aspects only and is not intended to be limiting of the subject matter. In case of a conflict in terminology, the present specification is controlling.

[0051]

[0038] As used herein, the term “ACTVIE” is an acronym for Acid Cleavage Triggered Via Ion Exchange processes as described herein.

[0052]

[0039] As used herein, ‘‘polymer” refers to the product of a polymerization reaction in which one or more monomers and / or repeat units are linked together.

[0053]

[0040] As used herein, “copolymer” refers to a polymer resulting from the polymerization of two or more chemically distinct monomers. A “block copolymer” refers to a polymer comprising blocks of monomers.

[0054]

[0041] The polymers and copolymers described herein can be prepared from any known ^-conjugated and conducting polymers. Polymers and copolymers can be brush-like, comb-like, branched or hyperbranched, crosslinked, or a mixture thereof.

[0055]

[0042] As used herein, the term “monomer” means any monomer that is polymerizable or copolymerizable and can form the backbone of a polymer or copolymer. Non-limiting examples of useful monomers include thiophene, 2,2'-bithiophene, thieno[3,2- b]thiophene, 2,3-dihydrothieno[3,4-b][l,4]dioxine, 2,2',3,3'-tetrahydro-5,5'-bithieno[3,4- b][ 1,4] di oxine, selenophene, such as:

[0056] Polythiophene More donating with sterics More donating

[0057]

[0043] As used herein, the term ‘‘monomer having a cleavable side chain” and the like means any monomer that is polymerizable or copolymerizable, can form the backbone of a polymer or copolymer and to which there is one or more cleavable side chains covalently bound. Cleavage of the side chain can be triggered by acid, base, light energy or heat.

[0058]

[0044] As used herein, the term “monomer having an acid cleavable side chain” and the like means any monomer that is polymerizable or copolymerizable, can form the backbone of a polymer or copolymer and to which there is one or more acid cleavable side chains covalently bound. Non-limiting examples include: tert-butyl thiophene-3-carboxylate tert-butyl (thiophen-3-ylmethyl) carbonate trimethyl(thiophen-3-yl)silane tert-butyl (thiophen-3-ylmethyl)carbamate 1-(thiophen-3-yl)ethyl acetate

[0059]

[0045] As used herein, the term “side chain” refers to a chain pendant to the main polymer chain. Examples of chemical structures of side chains include, but are not limited to alkane, tertiary ester, ester, poly ether, silane, carbamate and carbonate functionalities where the chain length of the attached alkyl can vary from 1 to 20 and the attached chain can be degradable polymers.

[0060]

[0046] The term '‘acid cleavable’’ and the like refers to a side chain, chemical group, motif or moiety that is chemically labile under acidic conditions.

[0061]

[0047] The term “acidic conditions’’ refers to generally a solution containing a Bronsted Acid with a minimum number of free protons, and conditions disclosed in the nonlimiting examples herein.

[0062]

[0048] As used herein, the term “stability” and “stable” and the like refers to a polymer or copolymer as described herein where its conductivity, as measured by known methods such as the ones described herein, remains substantially unchanged for an extended period of time, such as a week, a month, a year or more.

[0063]

[0049] As used herein, the term “simultaneously” refers to the initiation of cleaving and doping at the same time or near the same time and is distinguished from sequential cleaving and doping steps.

[0064]

[0050] As used herein, the term “residue” or “residue of’ a chemical moiety refers to a chemical moiety that is bound to a molecule, whereby through the binding, at least one covalent bond has replaced at least one atom of the original chemical moiety, resulting in a residue of the chemical moiety in the molecule. A residue can also be depicted as a structure either showing the replaced atom with a bond or the atom prior to replacement.

[0065]

[0051] As used herein, the term “semiconductor device” refers to a semiconductor substrate upon which at least one microelectronic device has been or is being fabricated.

[0066]

[0052] As used herein, the terms “contacting” and “mixing” and the like refer to reagents, such as macromonomers, in close proximity so that a reaction may occur.

[0067]

[0053] As used herein, “ambient temperature” or “room temperature” refers to a temperature in the range of about 20 to 25 °C. As used herein, “heat” refers to a temperature above ambient temperature, for example from about 50 to 300 °C.

[0068]

[0054] As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of a component, or an action, characteristic, property, state, structure, item, or result. The exact allowable degree of deviation from absolute presence of such a component, or an action, characteristic, property, state, structure, item, or result may in some cases depend on the specific context. However, generally speaking, “substantially” will be so near as to have the same overall result as if absolute and total extent or degree were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of a component, or an action, characteristic, property-, state, structure, item, or result. For example, a composition that is '‘substantially free of’ leaching would either completely lack leaching or so nearly completely lacking that the effect yvould be the same as if it completely lacked leaching. In other yvords, a composition that is “substantially free of’ leaching may still actually leach as long as there is no measurable effect thereof, for example, trace amounts. As used herein, “essentially free” means a component, or an action, characteristic, property, state, structure, item, or result is not present or is not detectable.

[0069]

[0055] As used herein, the term “disposed on"’ includes two layers that are in direct physical communication with each other without any intervening layers.

[0070]

[0056] Additional definitions may also be provided below.

[0071] II. Methods, Polymers and Copolymers, and Devices

[0072]

[0057] In certain embodiments, the subject matter described herein is directed to a method of preparing a doped polymer or copolymer, comprising: contacting a precursor polymer or copolymer yvith an acid dopant solution, wherein, the acid dopant solution comprises a dopant and an acid, and the precursor polymer or copolymer is a cleavable side chain-based polymer or copolymer, wherein, one or more side chains on the precursor polymer or copolymer are cleaved by the acid and the precursor polymer or copolymer is doped with the dopant to form the doped polymer or copolymer.

[0073]

[0058] In all embodiments, the cleaving and the doping is not performed in sequential steps.

[0074]

[0059] In certain embodiments, the doped polymer or copolymer has an increased conductivity compared to that of the corresponding precursor polymer or copolymer. In certain embodiments, the increased conductivity is from about two-fold to about IO9In certain embodiments, the increased conductivity is from about four-fold to about 50-fold. In certain embodiments, the increased conductivity is from about five-fold to about 10- fold. In certain embodiments, the increased conductivity is from about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45 or 50-fold . In certain embodiments, the increased conductivity of the doped polymer relative to the undoped polymer is a factor of 10, 102, 103. 104, 105, 106. 107, 108or 109

[0060] In certain embodiments, contacting comprises dipping, spraying, mixing or coating such that the acid dopant solution and the precursor polymer or copolymer are in physical contact with each other. In certain embodiments, contacting comprises dipping.

[0075]

[0061] The acid-dopant solution can comprise any known acid sufficient to develop acidic conditions. In certain embodiments, the acid has a pKa below about 3. In certain embodiments, the acid is selected from the group consisting of Tf2NH and TfOH. In certain embodiments, the acid is TfOH. In certain embodiments, the acid is present in the acid-dopant solution at an amount from about 1% to about 99% v / v.

[0076]

[0062] The acid-dopant solution also comprises a dopant that is able to donate or extract electron out of the polymer. In certain embodiments, the dopant is any known redox molecule(s) with appropriate energy levels against the polymer. A person of skill in this field can routinely determine the appropriate energy level. In certain embodiments, the dopant is FeCls, or F4TCNQ. In certain embodiments, the dopant is F4TCNQ. In certain embodiments, the dopant is present in the acid-dopant solution at an amount from about 1% to about 99% v / v.

[0077]

[0063] In certain embodiments, the acid-dopant solution comprises F4TCNQ and TfOH, in amounts effective for cleaving and doping, respectively.

[0078]

[0064] In certain embodiments, the precursor polymer or copolymer is a cleavable side chain-based polymer. In certain embodiments, the precursor polymer or copolymer is a cleavable side chain-based copolymer. In certain embodiments, the precursor polymer or copolymer is a cleavable side chain based conjugated polymer. In certain embodiments, the precursor polymer comprises wherein,

[0079] M is a monomer or block in the backbone of the polymer;

[0080] A is a cleavable side chain; and, n is an integer from 1 to 1 to 1 ,000.

[0081]

[0065] In certain embodiments, the cleavable side chain based conjugated polymer comprises a repeat unit, wherein the repeat unit comprises at least one cleavable side chain. In certain embodiments, the cleavable side chain based conjugated polymer comprises a repeat unit, wherein the repeat unit comprises at least one acid cleavable side chain. In certain embodiments, the cleavable side chain based conjugated polymer comprises a repeat unit, wherein the repeat unit comprises at least one acid cleavable side chain that is an ester. In certain embodiments, the cleavable side chain based conjugated polymer comprises a repeat unit, wherein the repeat unit comprises at least one acid cleavable side chain that is a tertiary ester motif. In certain embodiments, the cleavable side chain based conjugated polymer comprises a repeat unit, wherein the repeat unit comprises at least one acid cleavable side chain that is a tertiary ester-thiophene motif. For example, the cleavable side chain based conjugated polymer comprises one or more tertiary7ester-thiophene motifs. In certain embodiments, the cleavable side chain based conjugated polymer comprises

[0082] In certain embodiments, the cleavable side chain based conjugated polymer comprises

[0083] In certain embodiments, the cleavable side chain based conjugated polymer comprises

[0066] In certain embodiments, the precursor polymer or copolymer is in the form of a film.

[0084]

[0067] In certain embodiments, the doped polymer or copolymer comprises wherein,

[0085] M is a monomer or block in the backbone of the polymer; and, n is an integer from 1 to 1,000.

[0086]

[0068] In certain embodiments, the doped polymer or copolymer comprises

[0087] In certain embodiments, the doped polymer or copoly mer comprises

[0088] In certain embodiments, the doped polymer or copolymer comprises

[0089] In certain embodiments, the doped polymer or copolymer comprises

[0090]

[0069] In certain embodiments, the doped polymer or copolymer has a conductivity of greater than In certain embodiments, the doped polymer or copolymer has a conductivity from about 0. 1 S / cm to about 2,000 S / cm, or from about 0. 1 S / cm to about 600 S / cm.

[0091]

[0070] In certain embodiments, the doped polymer or copolymer is in the form of a film.

[0092]

[0071] In certain embodiments, the subject matter described herein is directed to a conductor material comprising the doped polymers or copolymers described herein for use in optoelectronic devices such as OLED (organic light emitting diode), OFET (organic field effect transistors), OPV (organic photovoltaics), and OECT (organic electrochemical transistors). The conductor material can be an ETL (electron transporting layer), or HTL (hole transporting layer) for example in an OLED.

[0093]

[0072] In certain embodiments, the subject matter described herein is directed to a semiconductor device comprising one or more of the doped polymers or copolymers described above.

[0094]

[0073] In a non-limiting example, a tertiary ester-thiophene motif was employed because it can eliminate side chain and leave behind the carboxylic acid via two different approaches: (i) direct cleavage between 150-220°C in neat films,16,20tracked by thermogravimetric analysis (TGA) (data not shown), or (ii) acid-induced cleavage at room temperature by soaking films in strong acid (pKa<-10) solutions,21evidenced by Fourier Transform Infrared (FT-IR) Spectroscopy (data not shown).

[0095]

[0074] Previous works on CSCPs10,13have shown that additional thiophene units can affect the carrier mobility ( / / ). Described herein are four exemplary- isomeric CSCPs - all containing 50 mol% of tertiary ester-thiophene units and 50 mol% thiophene units, to explore the relationships between structural design and conductive property (Scheme 1). These polymers include the first reported CSCP - regiorandom P3MOCT,20our regioregular RP-T50,10and two additional CSCPs named PIET-T2 and POET-T2. These additional polymers incorporate a twisted inw ard facing biester thiophene motif (IET) and a planar outward facing biester thiophene motif (OET), respectively. These orientations (twisted vs. planar) have been determined previously in single crystal analysis of similar linear-ester thiophene dimers.22 24

[0096]

[0075] The planar OET motif in POET-T2 may minimize the steric hindrance from tertiary carbon in polymer backbones and significantly increase the aggregation behavior; by contrast, the twisted IET motif in PIET-T2 would induce least aggregation. Indeed, POET-T2 is the only polymer that displayed significant temperature dependent aggregation in its chlorobenzene solution and vibrational peaks in its thin film before side chain cleavage (UV / Vis spectra, data not shown), whereas PIET-T2 shows almost no difference in its absorption profile between solution and thin film.

[0097]

[0076] The difference in positioning of 50 mol% tertiary ester-thiophene units in these four polymers has a strong impact in their energy levels, measured by cyclic voltammetry (CV) (data not shown). Since all four are structural isomers, the primary influence on the energy levels comes from the planarity’ of the backbone (i.e., effective conjugation length) and related aggregation behavior. The twisted PIET-T2 possesses the low est HOMO level, - 5.9 eV, and the planar POET-T2 in turn possesses the highest HOMO level, - 5.5 eV, comparable with that of archetypical P3HT in our measurement. The highest HOMO level of POET-T2 also positions it as the best candidate for efficient doping with F4TCNQ based on energetic alignment, followed by the P3MOCT. and RP-T50. While the thermal cleavage of side chains is well documented,18,25the acid-triggered cleavage was carried out by dipping the polymer thin film into a moisture exposed triflic acid (TfOH) solution (22.6 mM, 2pL TfOH in 1 mL acetonitrile) to cleave side chains and form the “CP-COOH’’ polymer. After acid-triggered cleavage, PIET-T2-COOH shows an increased HOMO level (- 5.9 eV - 5.7 eV), likely attributed to a more planar backbone. Other three polymers show very’ little change in their HOMO levels after cleaving side chains (Figure 1).

[0098]

[0077] With two different cleavage methods demonstrated, we next investigated strategies to combine doping with cleavage of side chains. There are tw o prevailing approaches to incorporate F4TCNQ as dopant into polymer films: blending in dopant into CP solutions then casting film (‘blend doping'; 10 wt% F4TCNQ in here), or dipping films into a solution of dopant (‘dip doping'; 3.6 mM of F4TCNQ or 1 mg / mL in acetonitrile in here). The screened combinations of doping and cleavage methods on the RP-T50 polymer are displayed in Figure 2.

[0099]

[0078] In Figure 2A, this region summarizes the key results representative of F4TCNQ doping of uncleaved RP-T50. The minor doping effect, evidenced by the low o, is attributed to the low u. of the uncleaved polymer and loyv n from poor energy alignment between the polymer and the dopant. Thermolysis at 200 °C (B region) results in dedoping of polymer films as F4TCNQ sublimes (data not shoyvn). Although RP-T50- COOH achieves 1000* higher g than the uncleaved RT-T5O,10subsequent dipping of cleaved films in F4TCNQ results in worse or similar conductivity to the uncleaved polymer (doped), as the dopant is likely unable to swell into the densified film (C region.)

[0079] Compared to thermal cleavage, acid-triggered cleavage shows a dramatic difference in conductivity, depending upon how the polymer film is doped (blue region). First, films subjected to TfOH show acidic protonation induced doping, which is well known for poly thiophenes.26,27Yet the achieved conductivity is much lower than those of films doped by F4TCNQ first prior to acid-tnggered cleavage (e.g., blend+TfOH), which can be ascribed to F4TCNQ’s higher electron affinity and faster integer charge transfer mechanism for doping.28However, subjecting neat polymer films to a mixed F4TCNQ / TfOH solution caused conductivity to increase six orders of magnitude to 8.5 S / cm from that of TfOH-only treated film. Without being bound to theory, this dramatic increase may be in part due to simultaneous swelling of dopants into polymer during the cleavage process, which can trap dopants after cleaving side chains. By contrast, sequential doping and cleavage (e.g., dip / blend+TfOH) would lose dopant by inversed diffusion into the TfOH solution. Interestingly UV / Vis spectrum of this film (data not shown) indicates that no F4TCNQ radical anion (F4TCNQ‘ ) peaks, which infers an ion exchange of the primary F4TCNQ‘ counterion with tri Hate (T I'O ) generated from TfOH protonating the polymer. Ion exchange has been shown to effectively increase dopant strength and stability.5,8,29Additionally, hydronium adducts formed with F4TCNQ may also be the source of increased dopant strength.30

[0100] Table 1. Comparison of Key Parameters of CSCPs with Different Doping Methods F4TCNQ+TfOH condition.

[0101]

[0080] Next, conventional F4TCNQ doping, TfOH cleavage with acid doping, and the optimized F4TCNQ+TfOH combined condition (named, ACTVIE) w as applied to the other three isomeric CSCPs and P3HT. Overall, the same trend prevails for each CP (including P3HT) where F4TCNQ doped films achieve a higher conductivity than the TfOH treated films (Figure 3 A). Only in the case of PIET-T2, where the energetic offset with F4TCNQ is the highest, does no doping of the CP occur in either condition.

[0102]

[0081] Advantageously, ACTVIE doping exhibits an unambiguously large conductivity7increase for all CSCPs, with values ranging from 0.0095 S / cm for PIET-T2-COOH to 353 S / cm for POET-T2-COOH. This large range of values reflect the critical importance of optimized polymer structure on achievable conductivity. Hall measurements of ACTVIE doped films show PIET-T2-COOH possessed the lowest fi (almost I Ox lower than P3MOCT-COOH) and lowest carrier concentration (Figure 2B and Table 1). Comparison of the regioregular RP-T50-COOH and the regiorandom P3MOCT-COOH reveals a minimal effect of regioregularity' on conductivity, where a higher n reflects the higher HOMO level of P3MOCT-COOH and the regioregularity of RP-T50-COOH likely accounts for its higher p,. Furthermore, the ACTVIE doping of P3HT did not result in an increased conductivity over conventional F4TCNQ based doping, although it does result in a greater photobleaching of its UV / Vis spectra (data not shown). This mismatch in bleaching and conductivity7is indicative of destructive oxidation of P3HT,31which is not expected for the CSCP-COOHs with oxidation tolerant carboxylates. Furthermore, all CSCP-COOHs show incomplete bleaching of their main absorption peak and the rise of a red shifted polaron / bipolaron band (data not shown), all without F4TCNQ’" absorbance, further supporting the ion exchange and the exclusive high doping efficiency of ACTVIE for CSCPs.

[0103]

[0082] POET-T2 doped through ACTVIE achieves the highest conductivity reported for a polythiophene-carboxylic acid. This is due primarily to the n which exceeds 1021cm’3with an estimated 0.9 carriers on every repeat unit (calculation not shown). Further, Hall measurements of POET-T2 doped with different methods (Figure 3C) show only the ACTVIE condition largely increased the n - over four orders of magnitude higher than TfOH or F4TCNQ doping. Comparing TfOH or F4TCNQ treated films also demonstrates the power of side chain cleavage to increase / / . with TfOH treated films achieving 100 x higher p. (1.0 cm2V’1s’1) than as cast films doped with F4TCNQ only (0.03 cm2V’1s’1).

[0104]

[0083] X-ray Photoelectron spectroscopy (XPS) was used to estimate the doping level, defined as number of polarons per thiophene ring. Specifically, the ratio of the sulfur in polaron to the sulfur in undoped polymer (Figure 7) can estimate the doping level,13’32 e.g., 33.6% in the case of ACTVIE doped POET-T2 (COOEI), much larger than F4TCNQ (11.8%) or TfOH (6.78%). This trend aligns well with the measured conductivity and n. From elemental analysis counts of N Is to F Is (data not shown), we also estimated that the counterion is 90% TfO”. Further, Time-of-Flight Secondary' Ion Mass Spectroscopy (ToF-SIMS) measurement (data not shown) shows that ACTVIE exclusively allows dopants to diffuse throughout the entire depth of the polymer thin film.

[0105] L84] We also applied ultraviolet photoelectron spectroscopy (UPS) to investigate the change of Fermi level and work function of doped POET-T2 films. As shown in Figure 4A and B and Table 2, ACTVIE doped POET-T2 (COOH) exhibits the Fermi level at almost the same energy as its HOMO level, indicative of metal like band structure.

[0106] Table 2.

[0107] A work function of 5.32 eV was calculated, which is deeper than many high conductivity’ CPs (e.g., PEDOT:PSS at 5.0 eV). Higher work function (0) materials are desirable since they can provide an Ohmic contact with the organic semiconductors in the active layer to promote charge extraction.33Unlike conventionally doped alky lated polymers (e.g., PBTTT doped with F4TCNQ), ACTVIE doped POET-T2 (COOH) possesses excellent solvent resistance (data not shown) where no decrease in conductivity’ occurs after soaking films in chloroform. Further analysis of doping stability showed complete retention of conductivity’ for 50 days in inert atmosphere, much better than F4TCNQ doped PBTTT (Figure 4C).34Additional stability' experiments (data not shown) in air and under heat (Figure 4D) revealed progressively less stability.

[0108]

[0085] The General Procedures and Examples provide exemplary’ methods for preparing compounds, copolymers and compositions. Those skilled in the art will appreciate that other synthetic routes may be used to synthesize the compounds. Although specific starting materials and reagents are depicted and discussed in the Schemes, General Procedures, and Examples, other starting materials and reagents can be easily substituted to provide a variety’ of derivatives and / or reaction conditions. In addition, many of the exemplary compounds prepared by the described methods can be further modified in light of this disclosure using conventional chemistry well knoyvn to those skilled in the art.

[0109]

[0086] The following examples are offered by way of illustration and not by way of limitation.

[0110] EXAMPLES

[0111] Materials and Methods

[0112]

[0087] Unless stated all reagents yvere purchased from commercial suppliers and used as received.

[0113]

[0088] General Characterization Tools — 'H nuclear magnetic resonance (NMR) measurements were recorded yvith Bruker DRX spectrometers (400 or 600 MHz). High temperature size exclusion chromatography (HT-SEC) was performed relative to the polystyrene standards in hot tri chlorobenzene at 135 °C or in standard tetrahydrofuran SEC relative to the polystyrene standards at room temperature. Absorption spectra were obtained with a Shimadzu UV-2600 spectrophotometer. Fourier Transform Infrared (FT- IR) spectra were taken on a Bruker Optics Hyperion 1000 yvith Tensor 27. The film thicknesses were recorded by a profilometer (KLA-Tencor D-100). Thermal gravimetric analysis yvas performed on a TA Instruments Q500 thermogravimetric analyzer under nitrogen atmosphere. X-ray photoelectron spectrometer (XPS) and ultraviolet photoelectron spectroscopy (UPS) were performed with a Kratos Axis Supra X-ray photoelectron spectrometer.

[0114] Example 1 — Syntheses

[0115]

[0089] Synthesis of Materials and Sidechain Cleavage — 5,5'-bis(trimethylstannyl)-2.2'- bithiophene (T2 monomer) and 2,5-bis(trimethylstannyl)thiophene (T1 monomer) were purchased from Sigma Aldrich and further purified through recrystallization in methanol before polymer synthesis. 2-bromohiophene-3-carboxylic acid, 2-bromothiophene-5- carboxylic acid and 2,5-dibromothiophene-3-carboxylic acid were purchased from Ambeed Chemical and used without further purification. The synthesis and purification of RP-T50 is described in reference 1. Esterification of thiophene-3 -carboxylic acids is described in reference 2.

[0116] Scheme 2.

[0117] (1): 2-methylhexan-2-yl 5-bromothiophene-3-carboxylate (2.984 g, 1 eq, 9.776 mmol), 4,4.4',4',5,5,5',5'-octamethyl-2.2'-bi(l,3,2-dioxaborolane) (1.241 g, 0.5 eq, 4.888 mmol), tri-tert-butylphosphonium tetrafluoroborate (170.2 mg, 0.06 eq, 586.6 pmol), and tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct (151.8 mg, 0.015 eq, 146.6 pmol) were added to a 200 rnL round bottom flask together with tetrahydrofuran (55 mL). After contents were dissolved, a separate solution of potassium carbonate (5.404 g. 4 eq, 39.10 mmol) in water (20 mL) was added, and the solution was left for 18 hours at 25 °C. The solution was then added to 200 mL of water and extracted 3 times with 200 mL of ethyl acetate. The crude product was then concentrated under vacuum and purified by silica gel column chromatography eluted with 1: 1 DCM:hexane, affording the product as a white powder, as bis(2-methylhexan-2-yl) [2,2'-bithiophene]-4,4'-dicarboxylate (1.220 g, 2.707 mmol, 55.38 %). 'H NMR (400 MHz, CDCL) 5 7.89 (d, J = 1.3 Hz, 2H), 7.51 (d, J = 1.3 Hz, 2H), 1.87 (m, 4H), 1.54 (s, 12H), 1.36 (m, 8H), 0.93 (m, 6H).

[0118] (2): OET monomer. Bis(2-methylhexan-2-yl) [2,2'-bithiophene]-4,4'-dicarboxylate (1.072 g, 1 eq, 2.379 mmol) was added to a 50 mL round bottom flask with DMF (20 mL). 1- Bromopyrrolidine-2,5-dione (846.8 mg, 2 Eq, 4.758 mmol) was added slowly to the flask and then raised to 60 °C and kept stirring for 18 hours. The reaction was then poured into water and the product was extracted 3 times with ethyl acetate. The product was further purified by column chromatography 1:1 DCM:hexane eluting the product as a white solid. The product was then recrystallized in methanol and collected via vacuum filtration as bis(2-methylhexan-2-yl) 5,5'-dibromo-[2,2'-bithiophene]-4,4'-dicarboxylate (0.87 g, 1.4 mmol, 60 %). 'H NMR (400 MHz, CDCh) 5 7.28 (s, 2H), 1.88 (m, 4H), 1.56 (s, 12H), 1.35 (m, 8H), 0.96 - 0.88 (m, 3H).

[0119] (3): 2-methylhexan-2-yl 2-bromothiophene-3-carboxylate (300 mg, 1 eq, 983 pmol), 4,4.4',4',5,5,5',5'-octamethyl-2.2'-bi(l,3,2-dioxaborolane) (125 mg, 0.5 eq, 491 pmol), tri- tert-butylphosphonium tetrafluoroborate (17.1 mg, 0.06 eq, 59.0 pmol), and tris(dibenzyfideneacetone)dipalladium(0)-chloroform adduct (15.3 mg, 0.015 eq, 14.7 pmol) were added to a 200 mL round bottom flask together with tetrahydrofuran (55 mL). After contents were dissolved, a separate solution of potassium carbonate (543 mg, 4 eq, 3.93 mmol) in water (20 mL) was added, and the solution was left for 18 hours at 25 °C. The solution was then added to 200 mL of water and extracted 3 times with 200 mL of ethyl acetate. The crude product was then concentrated under vacuum and purified by silica gel column chromatography eluted with 1 : 1 hexane:DCM, affording the product as a white powder as bis(2-methylhexan-2-yl) |2,2'-bithiopheneJ-3,3'-dicarboxylate (115 mg, 511 pmol, 52.0 %). 'H NMR (400 MHz, CDCh) 5 7.49 (d, J= 5.4 Hz, 2H), 7.30 (d, J= 5.4 Hz, 2H), 1.53 (m, 2H), 1.19 (m, 2H), 1.09 (m, 2H), 0.85 (m, 3H).

[0120] (4): IET monomer. Bis(2-methylhexan-2-yl) [2,2'-bithiophene]-3,3'-dicarboxylate (300 mg, 1 eq, 666 pmol) was added to a 50 mL round bottom flask with DMF (6 mL). 1- Bromopyrrolidine-2, 5-dione (592 mg, 5 eq, 3.33 mmol) was added slowly to the flask and then raised to 60 °C and kept stirring fori 8 hours. The reaction was then poured into water and the product was extracted 3 times with ethyl acetate. The product was further purified by column chromatography 1 : 1 DCM:hexane eluting the product as a clear oil as bis(2- methylhexan-2-yl) 5,5'-dibromo-[2,2'-bithiophene]-3,3'-dicarboxylate (188 mg, 310 pmol, 46.5 %). ‘H NMR (400 MHz, CDCh) 5 7.43 (s, 2H), 1.59 (m, 4H), 1.33 (s, 12H), 1.23 (m, 4H) 1.11 (m, 4H), 0.88 (m, 3H).

[0121] P3MOCT 2-Methylhexan-2-yl 2,5 -dibromothiophene-3 -carboxylate (192.1 mg, 1 eq. 0.5000 mmol), 2.5-bis(trimethylstannyl)thiophene (204.9 mg, 1 eq, 0.5000 mmol) and tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct (10.35 mg, 0.02 eq, 10.00 pmol) were added to a 10 mL round bottom flask. Vacuum and argon were cycled 3 times, 1 mL of o-xylene was then added, and the reaction was heated to 100 °C and kept stirring for 48 hours. The polymer was precipitated in methanol and purified by Soxhlet extraction with methanol, hexane and chloroform. The chloroform fraction was concentrated and precipitated in methanol and collected via filtration giving pure polymer (97 mg, 0.32 mmol, 63 %). 'H NMR (400 MHz, CDCh). Mn=22.6 kg / mol Mw=46.5 kg / mol D=2.05 (THF-GPC).

[0122] PIET-T2: IET (121.69 mg, 1 eq, 0.200 mmol), 5,5'-bis(trimethylstannyl)-2,2'-bithiophene (98.376 mg, 1 eq, 0.200 mmol), and tetrakis(triphenylphosphine)palladium(0) (4.6224 mg, 0.02 eq, 0.004 mmol) were added to a 10 mL round bottom flask. Vacuum and argon were cycled 3 times and 1 mL of o-xylene was added, and the reaction was heated to 100 °C and kept stirring for 48 hours. The polymer was precipitated in methanol and purified by Soxhlet extraction with methanol, hexane and chloroform. The chloroform fraction was concentrated and precipitated in methanol and collected via filtration (96 mg, 0. 152 mmol, 76%). 'H NMR (600 MHz, CDCh) 5 7.59 (m, 2H), 7.14 (m, 4H), 1.64 (m, 4H), 1.44 - 1.06 (m, 20 H), 0.96 - 0.79 (m, 6H). Mn=18.5 kg / mol Mw=36.4 kg / mol D=1.97 (THF-GPC).

[0123] POET-T2: GET (121.69 mg. 1 eq, 0.200 mmol), 5,5'-bis(trimethylstannyl)-2.2'- bithiophene (98.376 mg, 1 Eq, 0.200 mmol), and tetrakis(triphenylphosphine)palladium(0) (4.6224 mg, 0.02 eq, 0.004 mmol) were added to a 10 mL round bottom flask. Vacuum and argon were cycled 3 times and 1 mL of o- xylene was added, and the reaction was heated to 100 °C and kept stirring for 48 hours. The polymer was precipitated in methanol and purified by Soxhlet extraction with methanol, dichloromethane and chloroform. The thimble was then removed from the extractor and placed in a flask of boiling chlorobenzene to extract the polymer within 30 mins. This chlorobenzene fraction was then concentrated, precipitated in methanol and collected via filtration (106 mg, 0.169 mmol, 84%). 'H NMR at 90°C (600 MHz.

[0124] C2D2CI4) 5 7.50 (s, 2H), 7.39 (d, J= 3.8 Hz, 2H), 7.22 (d, J= 3.8 Hz, 2H), 1.82 (m, 4H), 1.55 (s, 12H), 1.38 - 1.19 (m, 8H), 0.91 (t, J= 6.8 Hz, 6H). Mn= 102.0 kg / mol Mw= 285.9 kg / mol D=2.8 (HT-GPC).

[0125] Example 2 — Side Chain Cleaving and Doping

[0126]

[0090] Precursor polymers were subjected to single step side chain cleaving and doping by dipping the polymers in an acid-dopant solution comprising 22.6 mM TfOH and 3.6 mM F4TCNQ. A 3.6 mM F4TCNQ solution was prepared in acetonitrile and TfOH was added for a 3.6mM concentration. Afterwards polymer films were submerged in this solution. The film was removed from solution after 30 mins and dried. Table 3. Film thickness (nM) of exemplary polymers at different doping conditions in Figure 3A.

[0127] Table 4. Film Thicknesses of all Polymers at Different Doping Conditions in Figure 3B and 3C.

[0128] Table 5. Data for Hall Measurement of POET-T2 under Different Doping Conditions

[0129] Table 6. Different dopant / acid conditions for the data in Figure 6.

[0130] Condition Conductivity (S / cm)

[0131] Undoped 2.08xl0'7±3.4xl0'8

[0132] TfOH 4.14X10'4±6.4X10'5

[0133]

[0091] The degree of doping can be estimated by the ratio of S 2pC to S 2p A:

[0134]

[0092] To obtain the values for the calculation, Figure 7A-C depicts the sulfur 2p XPS spectra deconvolution of differently doped POET-T2.

[0135] Example 3 — Conductivity'

[0136]

[0093] Conductivity data is reported elsewhere herein. To obtain data, glass substrates (1.5cmx 1.5cm) were precleaned by sequentially sonication for 15 mins each in deionized (DI) yvater with detergent, DI yvater (twice), acetone and isopropanol. The substrates were then dried under nitrogen gas flow and cleaned using UV-ozone treatment for 15 minutes. Subsequently, they were transferred to a nitrogen-filled glove box for further use. PIET- T2, P3MOCT, and PR-T50 yvere dissolved in chloroform at a concentration of 10 mg / mL and stirred for 3 hours at room temperature. POET-T2 was dissolved in chlorobenzene at 10 mg / mL and stirred for 3 hours at 100 °C. The polymer solutions were spin-cast onto the cleaned glass substrates. PIET-T2, P3MOCT, and RP-T50 yvere spun at 1000 rpm for

[0137] 1 minute, yvhile POET-T2 was spun at 2000 rpm for 2 minutes. The resulting polymer films were immersed in acetonitrile solutions containing dopants (F4TCNQ, TfOH, or a combination) for 30 minutes. The dopant concentrations yvere 1 mg / mL for F4TCNQ and

[0138] 2 μL / mL for TfOH. After carefully drying under nitrogen gas flow, the films were transferred to a vacuum chamber for silver electrode deposition. For PBTTT, it was dissolved in CB at a concentration of 10 mg / mL and stirred at 100 °C overnight. Then the hot PBTTT solution was spin-cast on the cleaned glass at 1000 rpm for 1 minute. The resulting polymer film was annealed at 150 °C for 1 hour and after cool to room temperature it was dipped in F4TCNQ solution in n-butyl acetate with a concentration of 5 mg / mL at 60 °C for 10 minutes. After carefully dried with nitrogen gas flow, the film was annealed again at 90 °C for 10 minutes. Then the film yvas transferred to the vacuum chamber for silver electrode deposition. An 80 nm silver layer was evaporated at 5 * 10'6mbar with a deposition rate of 0. 1 nm / second. The electrode pattern was defined using a shadow mask, with a channel length (spacing between electrodes) of 1 mm and a channel width (electrode width) of 9 mm. The current-voltage (I-V) characteristics were measured using a Keithley 2400 source meter employing a two-probe method. The conductivity was caculated as below where I / V is the slope of I-V curve, d is the channel length (1 mm), I is the film thickness, w is the channel width (9 mm).

[0139] Example 4 — Syntheses

[0140]

[0094] Synthesis of POET-T2

[0141]

[0095] Detailed information in the synthesis and purification of bis(2-methylhexan-2-yl) 5,5'-dibromo-[2,2'-bithiophene]-4,4'-dicarboxylate is described in a previous paper.35Stoichiometric imbalance was utilized to prepare a low molecular weight chloroform soluble fraction of POET-T2. bis(2-methylhexan-2-yl) 5,5'-dibromo-[2,2'-bithiophene]- 4,4'-dicarboxylate (128.1 mg, 1.00 Eq, 210.5 pmol), 5,5'-bis(trimethylstannyl)-2,2'- bithiophene (98.37 mg, 0.95 Eq, 0.2000 mmol) and 5,5'-bis(trimethylstannyl)-2,2'- bithiophene (98.37 mg, 0.95 Eq, 0.2000 mmol) were added to a 5 mL microwave vial. Vacuum and argon were cycled 3 times and 1 mL of o-xylene was added. The reaction was heated to 100 °C and kept stirring for 48 hours. The polymer was precipitated in methanol and purified by Soxhlet extraction with methanol, di chloromethane and chloroform. The chloroform fraction was concentrated and precipitated in methanol and collected via filtration to give POET-T2 (CF Fraction) (106 mg, 172 pmol. 81.9%). Mn= Separately, the thimble was then removed from the extractor and placed in a flask of boiling chlorobenzene to extract the higher molecular weight polymer fraction within 30 minutes. This chlorobenzene fraction was then concentrated, precipitated in methanol and collected via filtration to give POET-T2 (CB Fraction) (21 mg, 34 pmol, 16%).

[0142]

[0096] Synthesis of co-polymer (POET-T2so-stat-p(g32T-T2)5o) — bis(2-methylhexan-2- yl) 5,5'-dibromo-[2,2'-bithiophene]-4,4'-dicarboxylate (60.84 mg, 1 Eq, 0.1000 mmol), 5,5'-dibromo-3,3'-bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)-2,2'-bithiophene (64.84 mg, 1 Eq, 100.0 pmol) and 5,5'-bis(trimethylstannyl)-2,2'-bithiophene (98.37 mg,

[0143] 2 Eq, 200.0 pmol) were added to a 5 mL micro wave vial. Vacuum and argon were cycled

[0144] 3 times and 1 mL of o-xylene was added, and the reaction was heated to 100 °C and kept stirring for 24 hours. The polymer was precipitated in methanol and purified by Soxhlet extraction with acetone, ethyl acetate and chloroform. The chloroform fraction was concentrated and precipitated in methanol and collected via filtration POET-T25o-vtor- p(g32T-T2)5o (65 mg, 51 pmol, 51 %).

[0145]

[0097] Side-chain Cleavage — Acid-triggered side-chain cleavage is done by soaking polymer coated substrate for 5-10 min in 22.6 mM TfOH in acetonitrile solutions in room temperature.

[0146] Example 5 — Fabrication of OECTs

[0147]

[0098] To further evaluate mixed ionic-electronic conduction characteristics of this unique side-chain cleavable polymer POET-T2, conventional lateral-transport-ty pe OECTs using gel electrolytes were fabricated following the procedures detailed in the Methods section, and their device structure along with an optical micrograph is presented in Fig. 9a. The transfer characteristics of POET-T2-based devices before and after sidechain cleavage are shown in Fig. 9b-c, respectively. Upon side-chain cleavage, a notable enhancement in the on-current (Ion) was observed — from 2.22 to 8.32 mA at VD = 0.5 V and VG = -0.8 V — along with a discernable suppression of hysteresis which typically originates from constricted, slow; and unpredictable ion diffusion.36Notably, the / onof the cleaved POET-T2 is comparable to that of vertical-transport-type OECTs36, 37’38‘39, which rely on ultra-short channel lengths (under 100 nm) to boost Ion and gm. From a materials perspective, a more relevant figure of merit for evaluating the device property is the geometry -normalized transconductance (gm, norm) .40As shown in Fig. 9d, the gm, norm of cleaved POET-T2 reached 276.4 S cm1at VD = -0.5 V and VG = -0.6 V, underscoring its excellent signal transduction capability'. Compared to the uncleaved film, which exhibited gm, norm of approximately 98.5 S cm ', this corresponds to an increase of over 150%. The increase is ascribed to improved charge transport and doping capacity enabled by the removal of non-conductive, bulky side chains; this result presents anew opportunity to break the aforementioned trade-off between C* and n in the case of OEG polymers.

[0148]

[0099] The output characteristics exhibited a more pronounced enhancement upon sidechain cleavage, with the saturation current increasing nearly sixfold from 1.15 to 6.5 mA at VG = -0.8 V (Fig. 9e-f).

[0149]

[0100] Volumetric doping in OECTs allows geometry-dependent modulation of gm and response time (Fig. 9g-h). Both pristine and cleaved POET-T2 exhibited linear gmscaling with Wd / L, with the cleaved polymer showing a steeper slope corresponding to higher gm, norm. At higher Wd7L over 2 pm, both cleaved POET-T2 and pristine POET-T2 based devices reached saturation, presumably due to the contact resistance effects.39’40

[0150]

[0101] As the rise time (tr) of the OECT is generally considered a limiting factor for operational speed41, we plotted the rrvalues across various device geometries (Fig. 9h, Fig. lOa-d). Tr also scaled nearly linearly with channel volume42, and side-chain-cleaved POET-T2 based devices demonstrated more than a twofold improvement in operational speed. Although the absolute operational speed (~ 1 Hz) is still lower than that of previously reported OECTs (> 100 Hz)41, it is reasonable to assume that further optimization of the device scaling and electrolyte could substantially enhance the transient characteristics.

[0151]

[0102] Furthermore, side-chain removal markedly improved device stability, as shown in Fig. 9i. Cleaved POET-T2 exhibited nearly constant on-off characteristics over extended operation, whereas the pristine counterpart displayed unstable behavior and occasionally failed to turn on properly. Given that the primary’ cause of degradation in OECTs is morphological deterioration induced by trapped ions and repeated ionic diffusion within the polymer matrix42, data show that the enhanced ionic conductivity upon cleavage contributes to superior stability'.

[0152]

[0103] Fig. 9j presents the gm,norm of the polymers investigated in this study (details in Table 7 and Fig. 1 la-h). Overall, the co-polymer also exhibited an increase in gm,norm, but cleaved POET-T2 demonstrated the highest value reaching 270 S cm '. while conventional polymers appeared limited to approximately 150 S cm1Cleaved POET-T2 exhibited a / / C* value over 870 F cm 'V 's '. underscoring its exceptional performance.

[0153]

[0104] When operated with the polar electrolyte [EMIM][OTf], cleaved POET-T2 exhibited even higher gm norm exceeding 330 S cm1(Fig. 12a-g; Table 8). This enhancement is attributed to the presence of hydrophilic carboxylic acid groups formed after side-chain cleavage, which promote ion accessibility and facilitate strong interactions between polymer backbone and OTf" species. To the best of our knowledge, cleaved POET-T2 represent state-of-the-art values to date for OECTs43'60(Fig. 9k). By addressing tradeoffs between p and C* with side-chain cleavage, we successfully demonstrated that / LIC* can be further boosted through molecular engineering.

[0154]

[0105] For QECT fabrication. Au / Ti electrodes (36 / 4 nm) were deposited by thermal evaporation through a shadow mask onto pre-cleaned glass substrates. Polymer films were subsequently deposited by spin-coating the prepared solutions onto the substrates. No post-treatments, such as thermal annealing, were applied. Electrolyte solutions were prepared by dissolving PVDF-HFP in acetone at a weight ratio of 1:7 and stirring at 60 °C for at least 2 hours. Ionic liquids were then added to form PVDF-HFP / ionic liquid / acetone solutions with a weight ratio of 1 :4:7. These solutions were than spin- coated (1500 rpm, 60 seconds) onto pre-cleaned glass substrates to form gel electrolytes approximately 10 pm thick. The dried electrolyte films were cut with a razor blade and transferred to the desired positions. For the top electrode, PEDOT:PSS (PH1000) was drop-cast onto a hydrophobic substrate and annealed at 80 °C for 12 hours. To enhance conductivity, 10 vol% of ethylene glycol was added to the PEDOT:PSS solution and stirred for 20 minutes prior to casting. The resulting solid-state electrodes were cut with a razor blade and pasted onto the device at the desired positions.

[0155]

[0106] Table 7. Summarized device performances at VD = -0.5 V for various polymers using [EMIM][TFST]-based gel electrolyte. Data is calculated from transfer curves based on Bernards model. Mean ± range from at least six devices is reported.

[0156]

[0108] Efforts have been made to ensure accuracy with respect to numbers used (e g. amounts, temperature, etc.) but some experimental errors and deviations should be accounted for.

[0157]

[0109] One skilled in the art will recognize many methods and materials similar or equivalent to those described herein, which could be used in the practicing the subject matter described herein. The present disclosure is in no way limited to just the methods and materials described.

[0158]

[0110] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs, and are generally consistent with the Compendium of Chemical Terminology. IUPAC Recommendations, 2ndEd. 2019, available at https : / / goldbook. iupac. org.

[0159]

[0111] Throughout this specification and the claims, the words “comprise,” “comprises,” and “comprising” are used in a non-exclusive sense, except where the context requires otherwise. It is understood that embodiments described herein include “consisting of" and / or “consisting essentially of’ embodiments.

[0160]

[0112] As used herein, “and / or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”).

[0161]

[0113] The term “about” as used herein when referring to a measurable value, such as. for example, an amount or concentration and the like, is meant to encompass variations of 20%, ± 10%, ± 5%, ± 1%, ± 0.5%, or even ± 0.1% of the specified amount. A range provided herein for a measurable value may include any other range and / or individual value therein.

[0162]

[0114] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limit of the range and any other stated or intervening value in that stated range, is encompassed. The upper and lower limits of these small ranges which may independently be included in the smaller rangers is also encompassed, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0163]

[0115] Many modifications and other embodiments set forth herein will come to mind to one skilled in the art to which this subject matter pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the subject matter is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0164] BIBLIOGRAPHY

[0165] (1) Scaccabarozzi, A. D.; Basu, A.; Anies. F.; Liu, J.; Zapata-Arteaga, O.; Warren, R.; Firdaus, Y.; Nugraha, M. I.; Lin, Y.; Campoy-Quiles, M.; Koch, N.; Muller, C.; Tsetseris,

[0166] L.; Heeney, M.; Anthopoulos, T. D. Doping Approaches for Organic Semiconductors. Chem. Rev. 2022, 122 (4), 4420-4492. https: / / doi.org / 10.1021 / acs.chemrev. lc00581.

[0167] (2) Salzmann, L; Heimel, G. Toward a Comprehensive Understanding of Molecular Doping Organic Semiconductors (Review). J. Electron Spectros. Relat. Phenomena 2015, 204, 208-222. https: / / doi.Org / 10.1016 / j.elspec.2015.05.001.

[0168] (3) Stanfield, D. A.; Wu, Y.; Tolbert, S. H.; Schwartz, B. J. Controlling the Formation of Charge Transfer Complexes in Chemically Doped Semiconducting Polymers. Chem. Mater. 2021. 33 (7), 2343-2356.

[0169] (4) Kiefer, D.; Kroon, R.; Hofmann, A. L; Sun, H.; Liu, X.; Giovannitti, A.; Stegerer, D.; Cano, A.; Hynynen, J.; Yu, L.; Zhang, Y.; Nai, D.; Harrelson, T. F.; Sommer, M.; Moule, A. J.; Kemerink, M.; Marder, S. R.; McCulloch, L; Fahlman, M.; Fabiano, S.; Muller. C. Double Doping of Conjugated Polymers with Monomer Molecular Dopants. Nat. Mater. 2019, 18 (2), 149-155. https: / / doi.org / 10.1038 / s41563-018-0263-6.

[0170] (5) Jacobs, I. E.; Lin, Y.; Huang, Y.; Ren, X.; Simatos, D.; Chen, C.; Tjhe, D.; Statz,

[0171] M.; Lai, L.; Finn, P. A.; Neal, W. G.; D’Avino, G.; Lemaur, V.; Fratini, S.; Beljonne, D.; Strzalka, J.; Nielsen, C. B.; Barlow, S.; Marder, S. R.; McCulloch, L; Sirringhaus, H. High-Efficiency Ion-Exchange Doping of Conducting Polymers. Adv. Mater. 2022, 34 (22). https: / / doi.org / ! 0. 1002 / adma.202102988.

[0172] (6) Patel, S. N.; Glaudell, A. M.; Kiefer, D.; Chabinyc, M. L. Increasing the Thermoelectric Power Factor of a Semiconducting Polymer by Doping from the Vapor Phase. ACS Macro Lett. 2016, 5 (3), 268-272. https : / / doi. org / 10. 1021 / acsmacrolett.5b00887.

[0173] (7) Jin, W.; Yang, C. Y.; Pau, R.; Wang, Q.; Tekelenburg, E. K.; Wu, H. Y.; Wu, Z.; Jeong, S. Y.; Pitzalis, F.; Liu, T.; He, Q.; Li, Q.; Huang, J. Da; Kroon, R.; Heeney, M.; Woo. H. Y.; Mura, A.; Motta, A.; Facchetti, A.; Fahlman. M.; Loi, M. A.; Fabiano, S. Photocatalytic Doping of Organic Semiconductors. Nature 2024, 630. https: / / doi.org / 10.1038 / s41586-024-07400-5.

[0174] (8) Yamashita, Y.; Tsurumi, J.; Ohno, M.; Fujimoto, R.; Kumagai, S.; Kurosawa, T.; Okamoto, T.; Takeya, J.; Watanabe, S. Efficient Molecular Doping of Polymeric Semiconductors Driven by Anion Exchange. Nature 2019, 572 (7771), 634-638. https: / / doi.org / 10.1038 / s41586-019-1504-9.

[0175] (9) Jacobs, I. E.; D’avino, G.; Lemaur, V.; Lin, Y.; Huang, Y.; Chen, C.; Harrelson, T. F.; Wood, W.; Spalek, L. J.; Mustafa, T.; O’keefe, C. A.; Ren, X.; Simatos, D.; Tjhe, D.; Statz, M.; Strzalka, J. W.; Lee, J. K.; Mcculloch, I.; Fratini, S.; Beljonne, D.; Sirringhaus, H. Structural and Dynamic Disorder, Not Ionic Trapping, Controls Charge Transport in Highly Doped Conducting Polymers. J. Am. Chem. Soc. 2022, 144 (7),

[0176] 3005-3019. https : / / doi . org / 10. 1021 / j acs .1 c 10651.

[0177] (10) Son, S. Y.; Lee, G.; Wang, H.; Samson, S.; Wei, Q.; Zhu, Y.; You, W. Integrating Charge Mobility, Stability and Stretchability within Conjugated Polymer Films for Stretchable Multifunctional Sensors. Nat. Commun. 2022, 13. 2739. https: / / doi.org / 10.1038 / s41467-022-30361-0.

[0178] (11) Guo, C.; Quinn, J.; Sun, B.; Li, Y. An Indigo-Based Polymer Bearing Thermocleavable Side Chains for n-Type Organic Thin Film Transistors. J. Mater. Chem. C 2015, 3 (20). 5226-5232. https: / / doi.org / 10.1039 / c5tc00512d.

[0179] (12) Liu, C.; Dong, S.; Cai. P.; Liu. P.; Liu. S.; Chen, J.; Liu. F.; Ying. L.; Russell, T. P.; Huang, F.; Cao, Y. Donor-Acceptor Copolymers Based on Thermally Cleavable Indigo, Isoindigo, and DPP Units: Synthesis, Field Effect Transistors, and Polymer Solar Cells. ACS Appt. Mater. Interfaces 2015, 7 (17), 9038-9051. https : / / doi. org / 10. 102 l / am5089956.

[0180] (13) Ponder, J. F.; Gregory, S. A.; Atassi, A.; Menon, A. K.; Lang, A. W.; Savagian, L. R.; Reynolds, J. R.; Yee, S. K. Significant Enhancement of the Electrical Conductivity’ of Conjugated Polymers by Post-Processing Side Chain Removal. J. Am. Chem. Soc. 2022, 144 (3), 1351-1360. https: / / doi.org / 10.1021 / jacs. lcl l558.

[0181] (14) Ponder, J. F.; Gregory, S. A.; Atassi, A.; Advincula, A. A.; Rinehart, J. M.; Freychet, G.; Su, G. M.; Yee, S. K.; Reynolds, J. R. Metal-like Charge Transport in PEDOT ( OH ) Films by Post- Processing Side Chain Removal from a Soluble Precursor Polymer. Angew. Chemie 2023, 62, e202211600. https: / / doi.org / 10.1002 / anie.202211600.

[0182] (15) Zhao, H.; Shanahan, J. J.; Samson, S.; Li, Z.; Ma, G.; Prine, N.; Galuska, L.; Wang, Y.; Xia, W.; You, W.; Gu, X. Manipulating Conjugated Polymer Backbone Dynamics through Controlled Thermal Cleavage of Alkyl Side Chains. 2022, 43, 2200533. https: / / doi.org / 10.1002 / marc.202200533. (16) Krebs, F. C. Design and Applications of Polymer Solar Cells with Lifetimes Longer than 10000 Hours. Org. Photovoltaics VI 2005, 5938. 59380Y. https: / / doi.org / 10.1 117 / 12.613641.

[0183] (17) Sondergaard, R.; Helgesen, M.; Jorgensen, M.; Krebs, F. C. Fabrication of Polymer Solar Cells Using Aqueous Processing for All Layers Including the Metal Back Electrode. Adv. Energy Mater. 2011, 1, 68-71. https: / / doi.org / 10.1002 / aenm.201000007.

[0184] (18) Shanahan, J.; Oh. J.; Son, S. Y.; Siddika, S.; Pendleton, D.; O’Connor, B. T.; You, W. Strategic Incorporation of Cleavable Side Chains Improves Thermal Stability of PffBT-T4-Based Polymer Solar Cells. Chem. Mater. 2023, 35 (23), 10139-10149. https : / / doi . org / 10.1021 / acs. chemmater.3 c02181.

[0185] (19) Manceau. M.; Helgesen, M.; Krebs, F. C. Thermo-Cleavable Polymers: Materials with Enhanced Photochemical Stability. Polym. Degrad. Stab. 2010, 95 (12), 2666-2669. https: / / doi.Org / 10.1016 / j.polymdegradstab.2010.08.004.

[0186] (20) Liu, J.; Kadnikova, E. N.; Liu, Y.; McGehee, M. D.; Frechet, J. M. J. Polythiophene Containing Thermally Removable Solubilizing Groups Enhances the Interface and the Performance of Polymer-Titania Hybrid Solar Cells. J. Am. Chem. Soc. 2004, 126 (31), 9486-9487. https: / / doi.org / 10.1021 / ja047452m.

[0187] (21) Sondergaard, R. R.; Norrman, K.; Krebs, F. C. Low-Temperature Side-Chain Cleavage and Decarboxylation of Poly thiophene Esters by Acid Catalysis. J. Polym. Set. Part A Polym. Chem. 2012, 50 (6), 1127-1132. https: / / doi.org / 10.1002 / pola.25870.

[0188] (22) Lee, Y. W .; Lee, J.; Kim, J. Y. Regioisomeric Polythiophene Derivatives : Synthesis and Structure- Property Relationships for Organic Electronic Devices. Macromol. Res. 2020, 28 (8), 772-781. https: / / doi.org / 10.1007 / sl3233-020-8097-x.

[0189] (23) Pomerantz, M.; Amarasekara, A. S.; Dias, H. V. R. Synthesis and Solid-State Structures of Dimethyl 2 , 2 ' -Bithiophenedi carboxylates. J. Org. Chem. 2002, 67 (20), 6931-6937.

[0190] (24) Heuvel, R.; Colberts, F. J. M.; Wienk, M. M.; Janssen, R. A. J. Thermal Behaviour of Dicarboxy lie Ester Bithiophene Polymers Exhibiting a High Open-Circuit Voltage. J. Mater. Chem. C 2018, 6 (14), 3731-3742. https: / / doi.org / 10.1039 / c7tc04322h.

[0191] (25) Son, S. Y.; Samson, S.; Siddika, S.; O’Connor, B. T.; You, W. Thermocleavage of Partial Side Chains in Polythiophenes Offers Appreciable Photovoltaic Efficiency and Significant Morphological Stability. Chem. Mater. 2021, 33 (12), 4745-4756. https: / / doi.org / 10.1021 / acs. chemmater. 1 cOl 305. (26) Nguyen, P. H.; Schmithorst, M. B.; Mates, T. E.; Segalman, R. A.; Chabinyc, M. L. Diffusion of Bronsted Acidic Dopants in Conjugated Polymers f. J. Mater. Chem. C 2023, 11, 7462-7470. https: / / doi.org / 10.1039 / d3tc00415e.

[0192] (27) Hofmann, A. I.; Kroon, R.; Yu, L.; Muller, C. Highly Stable Doping of a Polar Polythiophene through Co-Processing with Sulfonic Acids and Bistriflimide. J. Mater. Chem. C 2018, 6 (26), 6905-6910. https: / / doi.org / 10.1039 / C8TC01593G.

[0193] (28) Salzmann, I.; Heimel, G.; Oehzelt, M.; Winkler, S.; Koch, N. Molecular Electrical Doping of Organic Semiconductors: Fundamental Mechanisms and Emerging Dopant Design Rules. Acc. Chem. Res. 2016, 49 (3), 370-378. https: / / doi.org / 10.1021 / acs.accounts.5b00438.

[0194] (29) Wang, S.; Zhu. W.; Jacobs, I. E.; Wood. W. A.; Wang, Z.; Manikandan, S.; Andreasen, J. W.: Un, H. I.; Ursel, S.; Peralta, S.; Guan, S.; Grivel, J. C.; Longuemart, S.; Sirringhaus, H. Enhancing the Thermoelectric Properties of Conjugated Polymers by Suppressing Dopant-Induced Disorder. Adv. Mater. 2024, 36. 2314062. https : / / doi.org / 10.1002 / adma.202314062.

[0195] (30) Hyun Suh, E.; Beom Kim, S.; Jung, J.; Jang, J. Extremely Electron-Withdrawing Lewis-Paired CN Groups for Organic p-Dopants. Angew. Chemie - Int. Ed. 2023, 62 (37). https: / / doi.org / 10.1002 / anie.202304245.

[0196] (31) Aoyama, Y.; Yamanari, T.; Koumura, N.; Tachikawa, H.; Nagai, M.; Yoshida, Y. Photo-Induced Oxidation of Polythiophene Derivatives: Dependence on Side Chain Structure. Polym. Degrad. Stab. 2013, 98 (4), 899-903. https: / / doi.Org / 10.1016 / j.polymdegradstab.2013.01.006.

[0197] (32) Gregory. S. A.; Hanus, R.; Atassi, A.; Rinehart, J. M.; Wooding, J. P.; Menon, A. K.; Losego, M. D.; Snyder, G. J.; Yee. S. K. Quantifying Charge Carrier Localization in Chemically Doped Semiconducting Polymers. Nat. Mater. 2021, 20 (10), 1414-1421. https: / / doi.org / 10.1038 / s41563-021-01008-0.

[0198] (33) Tan, J. K.; Png, R. Q.; Zhao, C.; Ho, P. K. H. Ohmic Transition at Contacts Key to Maximizing Fill Factor and Performance of Organic Solar Cells. Nat. Commun. 2018, 9, 3269. https: / / doi.org / 10.1038 / s41467-018-05200-w.

[0199] (34) DeLongchamp, D. M.; Kline, R. J.: Lin, E. K : Fischer, D. A.; Richter, L. J.; Lucas, L. A.; Heeney, M.; McCulloch, L; Northrup, J. E. High Carrier Mobility Polythiophene Thin Films: Structure Determination by Experiment and Theory. Adv. Mater. 2007. 19 (6), 833-837. https: / / doi.org / 10.1002 / adma.200602651. (35) Shanahan J, Yan L, Olanrewaju Y, Kashani S, Ade H, So F, You W. Acid- Triggered Side Chain Cleavage Leads to Doped Conjugated Polymers of High Conductivity. Journal of the American Chemical Society 2024, 146(47): 32243-32248.

[0200] (36) Huang W, Chen J, Yao Y, Zheng D, Ji X, Feng L-W, et al. Vertical organic electrochemical transistors for complementary circuits. Nature 2023, 613(7944): 496- 502.

[0201] (37) Kim J, Pankow RM, Cho Y, Duplessis ID, Qin F, Meh D. et al. Monolithically integrated high-density vertical organic electrochemical transistor arrays and complementary’ circuits. Nature Electronics 2024, 7(3): 234-243

[0202] (38) Li T, Qu Z, Si J, Lee Y, Bandari VK, Schmidt OG. Monolithically integrated solid-state vertical organic electrochemical transistors switching between neuromorphic and logic functions. Science Advances, 11(1 1): eadt5186.

[0203] (39) Donahue MJ, Williamson A, Strakosas X, Friedlein JT, McLeod RR, Gleskova H, Malliaras GG. High-Performance Vertical Organic Electrochemical Transistors.

[0204] Advanced Materials 2018, 30(5): 1705031.

[0205] (40) Friedlein JT, McLeod RR, Rivnay J. Device physics of organic electrochemical transistors. Organic Electronics 2018, 63: 398-414.

[0206] (41) Guo J, Chen SE, Giridharagopal R, Bischak CG, Onorato JW, Yan K, et al. Understanding asymmetric switching times in accumulation mode organic electrochemical transistors. Nature Materials 2024, 23(5): 656-663.

[0207] (42) Zhao C, Yang J, Ma W. Transient Response and Ionic Dynamics in Organic Electrochemical Transistors. Nano-Micro Letters 2024, 16(1): 233.

[0208] (43) Pyo WJ, Lee S, Hassan SZ, Kim D, Jung J, Kang ESH, Chung DS. Internalization of Ionic Transport Ability of Polymer Semiconductors via Photochemical Cross-Linking. ACS Nano 2025, 19(5): 5801-5810.

[0209] (44) Chen J, Huang W, Zheng D, Xie Z, Zhuang X, Zhao D, et al. Highly stretchable organic electrochemical transistors with strain-resistant performance. Nature Materials 2022. 21(5): 564-571.

[0210] (45) DiTullio BT, Savagian LR, Bardagot O, De Keersmaecker M, Osterholm AM, Baneiji N, Reynolds JR. Effects of Side-Chain Length and Functionality on Polar Poly(dioxythiophene)s for Saline-Based Organic Electrochemical Transistors. Journal of the American Chemical Society 2023, 145(1): 122-134.

[0211] (46) Moser M, Hidalgo TC. Surgailis J. Gladisch J. Ghosh S. Sheelamanthula R. et al. Side Chain Redistribution as a Strategy' to Boost Organic Electrochemical Transistor Performance and Stability. Advanced Materials 2020. 32(37): 2002748.

[0212] (47) Hallani RK, Paulsen BD, Petty AJ, II, Sheelamanthula R, Moser M, Thorley KJ, et al. Regiochemistry-Driven Organic Electrochemical Transistor Performance Enhancement in Ethylene Glycol-Functionalized Polythiophenes. Journal of the American Chemical Society 2021, 143(29): 11007-11018.

[0213] (48) Schmode P, Savva A, Kahl R, Ohayon D, Meichsner F, Dolynchuk O, et al. The Key Role of Side Chain Linkage in Structure Formation and Mixed Conduction of Ethylene Glycol Substituted Polythiophenes. ACS Applied Materials & Interfaces 2020, 12(11): 13029-13039.

[0214] (49) Moser M, Savagian LR, Savva A, Matta M, Ponder JF, Jr., Hidalgo TC. et al. Ethylene Glycol-Based Side Chain Length Engineering in Polythiophenes and its Impact on Organic Electrochemical Transistor Performance. Chemistry of Materials 2020, 32(15): 6618-6628.

[0215] (50) Paulsen BD, Meli D, Moser M, Marks A, Ponder JF, Jr., Wu R et al. Enhancement of Conjugated Polymer Microstructure and Mixed-Conducting Properties via Chalcogenophene Heteroatom Substitution. Chemistry of Materials 2024, 36(4): 1818-1830.

[0216] (51) Lan L, Chen J, Wang Y, Li P, Yu Y, Zhu G, et al. Facilely Accessible Porous Conjugated Polymers toward High-Performance and Flexible Organic Electrochemical Transistors. Chemistry of Materials 2022, 34(4): 1666-1676.

[0217] (52) Halaksa R, Kim JH, Thorley KJ, Gilhooly-Finn PA, Ahn H, Savva A et al. The Influence of Regiochemistry on the Performance of Organic Mixed Ionic and Electronic Conductors. Angewandte Chemie International Edition 2023, 62(29): e202304390.

[0218] (53) Parr ZS, Halaksa R, Finn PA, Rashid RB, Kovalenko A, Weiter M, et al.

[0219] Glycolated Thiophene-Tetrafluorophenylene Copolymers for Bioelectronic Applications: Synthesis by Direct Heteroarylation Polymerisation. ChemPlusChem 2019, 84(9): 1384- 1390.

[0220] (54) Moser M, Savva A, Thorley K, Paulsen BD, Hidalgo TC, Ohayon D, et al. Polaron Delocalization in Donor-Acceptor Polymers and its Impact on Organic Electrochemical Transistor Performance. Angewandte Chemie International Edition 2021, 60(14): 7777-7785.

[0221] (55) Cong S, Chen J, Ding B, Lan L, Wang Y, Chen C. et al. Tunable control of the performance of aqueous-based electrochemical devices by post-polymerization functionalization. Materials Horizons 2023, 10(8): 3090-3100.

[0222] (56) Cong S, Chen J, Xie M, Deng Z, Chen C, Liu R, et al. Single ambipolar OECT- based inverter with volatility and nonvolatility on demand. Science Advances, 10(41): eadq9405.

[0223] (57) Kim JH, Halaksa R, Jo I-Y, Ahn H, Gilhooly-Finn PA, Lee I, et al. Peculiar transient behaviors of organic electrochemical transistors governed by ion injection directionality. Nature Communications 2023, 14(1): 7577.

[0224] (58) Kim S-M, Kim C-H, Kim Y, Kim N, Lee W-J, Lee E-H, et al. Influence of PEDOT:PSS crystallinity and composition on electrochemical transistor performance and long-term stability. Nature Communications 2018, 9(1): 3858.

[0225] (59) Lee S, Kim D, Meresa AA, Chang ST, Kim FS. Compatibility of cellulose- PEDOT:PSS composites and anions in solid-state organic electrochemical transistors. Carbohydrate Polymers 2025, 352: 123146.

[0226] (60) Qiu J. Sheng Q, Qian X, Yao J, Zhao Y, Zhang X et al. Vertically Phase- Separated PEDOT:PSS Film via Solid-Liquid Interface Doping for Flexible Organic Electrochemical Transistors. ACS Applied Materials & Interfaces 2025, 17(1 1): 17202- 17216.

[0227] (61) Wu X, Stephen M, Hidalgo TC, Salim T, Surgailis J, Surendran A el al. Ionic- Liquid Induced Morphology Tuning of PEDOT:PSS for High-Performance Organic Electrochemical Transistors. Advanced Functional Materials 2022, 32(1): 2108510.

Claims

THAT WHICH IS CLAIMED:

1. A method of preparing a doped polymer or copolymer, comprising: contacting a precursor polymer or copolymer with an acid dopant solution, wherein, the acid dopant solution comprises a dopant and an acid, and the precursor polymer or copolymer is a cleavable side chain based polymer or copolymer, wherein, one or more side chains on the precursor polymer or copolymer are cleaved by the acid and the precursor polymer or copolymer is doped with the dopant to form the doped polymer or copolymer.

2. The method of claim 1 , wherein the doped polymer or copolymer has an increased conductivity compared to that of the corresponding precursor polymer or copolymer.

3. The method of claim 2, where the increased conductivity is from about two-fold to about 109.

4. The method of claim 2, where the increased conductivity’ is from about four-fold to about 50-fold.

5. The method of claim 1 , yvherein the contacting comprising dipping, spraying or coating.

6. The method of any one of claims 1-5, wherein the acid dopant solution comprises an acid having a pKa beloyv about 3.

7. The method of claim 6, wherein the acid is selected from the group consisting of Tf2NH and TfOH.

8. The method of claim 7, yvherein the acid is TfOH.

9. The method of any one of claims, 1-8, wherein the dopant is a redox molecule with appropriate energy levels against the polymer.

10. The method of claim 9, wherein the dopant is FeCh or F4TCNQ.

11. The method claim 10, wherein the dopant is F4TCNQ.

12. The method of any one of claims 1-11. wherein the acid dopant solution comprises F4TCNQ and TfOH.

13. The method of any one of claims 1-12, wherein the precursor polymer or copolymer is a cleavable side chain based polymer.

14. The method of any one of claims 1-12, wherein the precursor polymer or copolymer is π - conjugated or conducting polymer or copolymer comprising a repeat unit, wherein the repeat unit comprises at least one acid cleavable side chain.

15. The method of any one of claims 1-14, wherein the precursor polymer or copolymer is a 7t-conjugated or conducting polymer or copolymer comprising a repeat unit, wherein the repeat unit comprises at least one acid cleavable side chain that is an ester.

16. The method of claim 15, wherein the precursor polymer compriseswherein,M is a monomer or block in the backbone of the polymer; A is an acid cleavable side chain; and, n is an integer from 1 to 1,000.

17. The method of claim 16, wherein the cleavable side chain based conjugated polymer comprises one or more tertiary7ester-thiophene motifs.

18. The method of claim 17, wherein the cleavable side chain based conjugated polymer comprises19. The method of claim 18, wherein the cleavable side chain based conjugated polymer comprises20. The method of claim 16, wherein the cleavable side chain based conjugated polymer comprises21. The method of any one of claims 1-20. wherein the precursor polymer or copolymer is in the form of a film.

22. The method of any one of claims 1-21, wherein the doped polymer or copolymer compriseswherein,M is a monomer or block in the backbone of the polymer; and. n is an integer from 1 to 1,000.

23. The method of claim 22, wherein the doped polymer or copolymer comprises24. The method of any one of claims 1-23, wherein the amount of dopant present in the doped polymer or copolymer is from about 0.1 mol% to about 99 mol%25. A doped polymer or copolymer comprising, a polymer comprisingwherein,M is a monomer or block in the backbone of the polymer; and, n is an integer from 1 to 1,000; and, a dopant, wherein, the amount of dopant present in the doped polymer or copolymer is from about 0. 1 mol% to about 99 mol%.

26. The doped polymer or copolymer of claim 25, having a conductivity greater than 2.4 x IO’7S / cm.

27. The doped polymer or copolymer of claim 26, having a conductivity' from about 0.1 S / cm to about 2,000 S / cm.

28. The doped polymer or copolymer of any one of claims 25-27, comprising<img src='' class="img-anchor img-center" img-id="IMGF000045_0001" / >29. The doped polymer or copolymer of claim 28, comprising30. The doped polymer or copolymer of any one of claims 25-28, comprisingThe doped polymer or copolymer of claim 30, comprising32. The doped poly mer or copolymer of claim 25 in the form of a film.

33. The doped polymer or copolymer of any one of claims 25-32 prepared by the method of any one of claims 1-24.

34. A semiconductor device comprising the doped polymer or copolymer of claim 25 or 33.

35. A conductor material comprising the doped polymer or copolymer of claim 25 or 33.

36. An optoelectronic device comprising the semiconductor of claim 34 or the conductor material of claim 35.

37. The optoelectronic device of claim 36 selected from the group consisting of OLED (organic light emitting diode), OFET (organic field effect transistors). OPV (organic photo voltai cs), and OECT (organic electrochemical transistors).

38. An organic electrochemical transistor device comprising: a substrate; a source electrode and a drain electrode disposed on a top surface of the substrate; and an active layer disposed on the top surface of the substrate and in electrical contact with the source electrode and the drain electrode, wherein the active layer comprises a doped polymer or copolymer comprising, a polymer comprisingwherein,M is a monomer or block in the backbone of the polymer; and, n is an integer from 1 to 1,000; and, a dopant, wherein, the amount of dopant present in the doped polymer or copolymer is from about 0.1 mol% to about 99 mol%.

39. The organic electrochemical transistor device of claim 38. wherein the substrate comprises a flexible substrate.

40. The organic electrochemical transistor device of claim 38, wherein the doped polymer or copolymer has a conductivity greater than 2.4 x 10’7S / cm.

41. The organic electrochemical transistor device of claim 38. wherein the doped polymer or copolymer has a conductivity from about 0.1 S / cm to about 2,000 S / cm.

42. The organic electrochemical transistor device of claim 38, wherein the doped polymer or copolymer comprises43. The organic electrochemical transistor device of claim 42, wherein the doped polymer or copolymer comprises44. The organic electrochemical transistor device of claim 38. wherein the doped polymer or copolymer comprises45. The organic electrochemical transistor device of claim 44, wherein the doped polymer or copolymer comprises46. The organic electrochemical transistor device of claim 38. wherein the doped polymer or copolymer is POET-T2so-stat-p(g32T-T2)5o.

47. The organic electrochemical transistor device of claim 38, further comprising an electrolyte disposed on the surface of the active layer opposite the substrate.

48. The organic electrochemical transistor device of claim 38 having improved stability.

49. The doped polymer or copolymer of claim 25. having a conductivity of from about 160 S cm' Ho about 380 S cm'1.

50. The doped polymer or copolymer of claim 49, having a conductivity of about 270 S cm1.

51. A method of increasing the piC* of an organic electrochemical transistor device, comprising incorporating a doped polymer or copolymer of claim 25 into the active layer of the device.

52. A method of manufacturing an organic electrochemical transistor device, the method comprising: an electrode forming step of forming a source electrode and a drain electrode on a top surface of a substrate; and an active layer forming step of forming an active layer comprising a doped polymer or copolymer of claim 25 on the top surface of the substrate to be in electrical contact with the source electrode and the drain electrode.

Images