An organic small molecule modified tin oxide-based organic solar cell device and a preparation method thereof

Abstract

The application discloses a kind of tin oxide-based organic solar cell devices based on organic small molecule modification and preparation method thereof.The battery device structure of the application is sequentially from bottom to top: transparent substrate, conductive cathode, electron transport layer, photoactive layer, hole transport layer and metal anode, the electron transport layer is composed of lower metal tin oxide and upper small molecule (2-(3-1,10-phenanthroline group)-6-naphthyl) diphenyl phosphine oxide composite electron transport layer, under the condition of AM1.5G light source, 27.64mA·cm ‑2 Short-circuit current is obtained, and fill factor is increased to 74.93%, and more than 17% photoelectric conversion efficiency is realized, which has great application prospect in future engineering application.

Description

Technical Field

[0001] This invention belongs to the field of organic solar cell devices, specifically relating to a tin oxide-based organic solar cell device modified with organic small molecules and its preparation method. Background Technology

[0002] The lightweight, simple fabrication, low cost, and flexible processing characteristics of photovoltaic technology make organic solar cells a promising solar energy collection technology. Thanks to continuous advancements in active layer materials and device physics, the photoelectric conversion efficiency (PCE) of organic solar cells has exceeded 19%. Excellent PCE is one of the three key parameters for the industrialization of organic solar cells (the other two being stability and cost). However, current developments in stability and cost lag far behind those in PCE. Therefore, how to fabricate organic solar cells that combine high PCE, long-term stability, and low cost is a problem that needs to be solved.

[0003] Flip-chip structures are an effective way to improve stability. The device consists of ITO (cathode) / metal oxide / active layer / metal (anode), where the metal oxide is deposited on the ITO cathode as an electron transport layer. Currently, TiO2 and ZnO are widely used metal oxides for the electron transport layer, mainly due to their high transparency and suitable work function. However, they also have some drawbacks, such as the low electron mobility of TiO2, the instability of TiO2 and ZnO, and the high-temperature processing requirements of TiO2. Tin dioxide is one of the best electron transport materials in perovskite solar cells because of its high transparency, lack of light wetting, ultra-high electron mobility, good chemical and light stability, and hole blocking ability. Despite its excellent electron transport performance, tin oxide is rarely used in organic solar cells. This is partly because the tin oxide surface has many defects (such as dangling metallic bonds and free hydroxyl groups), leading to severe trap-assisted recombination at the surface, requiring surface modification to ensure compatibility with the active layer. On the other hand, the energy band of tin oxide differs significantly from that of the LUMO of the acceptor material, which is not conducive to the rapid transport of charge and its extraction by the electrode. It is necessary to overcome the contact barrier between the N-type metal oxide and the LUMO of the active layer acceptor.

[0004] Therefore, improving the efficiency of tin oxide-based organic solar cell devices is a technical challenge that needs to be addressed. Summary of the Invention

[0005] To address the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a tin oxide-based organic solar cell device modified with small organic molecules, thereby improving the fill factor and short-circuit current of the tin oxide organic solar cell and achieving high photoelectric conversion efficiency.

[0006] This invention utilizes the surface coordination of N-type wide-bandgap small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) with tin oxide to improve the photoelectric properties of the electron transport layer and enhance the charge transport rate. The more balanced charge transport rate is beneficial to improving the fill factor and photoelectric conversion efficiency of photovoltaic devices, thereby preparing a high-efficiency and stable organic solar cell based on tin oxide.

[0007] Another object of the present invention is to provide a method for preparing a tin oxide-based organic solar cell device based on organic small molecule modification.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A tin oxide-based organic solar cell device modified with organic small molecules has the following structure from bottom to top: a transparent substrate, a conductive cathode, an electron transport layer, a photoactive layer, a hole transport layer, and a metal anode;

[0010] The electron transport layer is composed of a lower tin oxide layer and an upper small molecule material (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) layer.

[0011] Preferably, the thickness of the tin oxide layer is 5–40 nm; more preferably, it is 10 nm.

[0012] Preferably, the structural formula of the small molecule (2-(3-1,10-phenanthrolinel)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) is as follows:

[0013]

[0014] Preferably, the thickness of the upper small molecule material (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) layer is 3-10 nm; more preferably 5-10 nm, and most preferably 5 nm.

[0015] Preferably, the upper small molecule material (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) layer is prepared by solution spin coating; the spin coating speed is 1000-3000 rpm, the time is 30-60 s, and the solution concentration is 0.5-2 mg / ml.

[0016] Preferably, the thickness of the photoactive layer is 50–400 nm.

[0017] Preferably, the photoactive layer is prepared by polymer donor material PM6 and acceptor molecule Y6 at a donor-to-acceptor mass ratio of 1:0.8 to 1.6. More preferably, the donor-to-acceptor mass ratio is 1:1.2.

[0018] More preferably, the photoactive layer is obtained by spin-coating a polymer donor material PM6 and an acceptor molecule Y6 into a film and then thermally annealing it.

[0019] More preferably, the solvent in the solution is at least one of chlorobenzene, chloroform, and o-xylene.

[0020] The structural formula of the polymer donor material PM6 is as follows:

[0021]

[0022] Its molecular weight is 15–60 kDa.

[0023] The structural formula of the receptor molecule Y6 is as follows:

[0024]

[0025] Preferably, the transparent substrate is one of transparent glass or polyimide film. Preferably, the conductive cathode is at least one of indium tin oxide and tin fluoride oxide. Preferably, the thickness of the conductive cathode is 80–180 nm.

[0026] Preferably, the hole transport layer is molybdenum oxide.

[0027] Preferably, the thickness of the hole transport layer is 5–15 nm.

[0028] Preferably, the hole transport layer is constructed by a vacuum deposition method.

[0029] Preferably, the metal anode is at least one of gold, silver, aluminum, and calcium.

[0030] Preferably, the thickness of the metal anode is 80–120 nm.

[0031] Preferably, the metal anode is constructed by a vacuum deposition method.

[0032] The above-mentioned method for preparing a tin oxide-based organic solar cell device modified with small organic molecules includes the following steps:

[0033] (1) A tin oxide layer was prepared on a conductive cathode by spin coating;

[0034] (2) A small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) was spin-coated onto a tin oxide layer to obtain an electron transport layer;

[0035] (3) The donor material PM6 and the acceptor molecule Y6 were spin-coated onto the electron transport layer by solution spin coating and then annealed to obtain the photoactive layer.

[0036] (4) A hole transport layer is prepared on the photoactive layer;

[0037] (5) Prepare a metal anode on the hole transport layer.

[0038] Preferably, the tin oxide layer in step (1) is obtained by spin-coating an aqueous solution of tin oxide nanoparticles onto a conductive cathode and then annealing it.

[0039] More preferably, the solid content of the aqueous solution of tin oxide nanoparticles is 1.5% to 3%.

[0040] More preferably, the spin coating speed is 2000-4000 rpm and the spin coating time is 40-60 s.

[0041] More preferably, the annealing treatment is performed at a temperature of 150–200°C for a time of 30–60 minutes.

[0042] Preferably, the spin coating in step (2) refers to spin coating a small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) solution onto a tin oxide layer, with a solution concentration of 0.5-2 mg / ml.

[0043] More preferably, the solvent for the small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) solution is methanol.

[0044] More preferably, the spin coating speed is 1000-3000 rpm and the time is 30-60 s.

[0045] Preferably, the total concentration of the solution in step (3) is 13-20 mg / ml.

[0046] Preferably, the solvent of the solution in step (3) is at least one of chlorobenzene, chloroform and o-xylene.

[0047] Preferably, the spin coating speed in step (3) is 2000-4000 rpm and the spin coating time is 20-60 s.

[0048] Preferably, the annealing treatment in step (3) is performed at a temperature of 90–120°C for 3–30 minutes.

[0049] Preferably, the hole transport layer in step (4) is prepared by vacuum deposition.

[0050] Preferably, the metal anode in step (5) is prepared by vacuum deposition.

[0051] Preferably, the area of ​​the tin oxide-based organic solar cell device modified with small organic molecules is 0.0314–10 cm². 2 .

[0052] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0053] (1) The preparation method of the present invention is simple, the material cost is low, and it is feasible.

[0054] (2) The small molecule-modified tin oxide-based organic solar cell device of the present invention achieves 27.64 mA·cm² under AM1.5G light source conditions. -2 The short-circuit current was reduced, and the fill factor was increased to 74.93%, achieving a photoelectric conversion efficiency of over 17%.

[0055] (3) The organic solar cell described in this invention improves the photoelectric conversion efficiency by more than 8% compared with the unmodified device, and has great application prospects in future engineering applications. Attached Figure Description

[0056] Figure 1 This is a graph showing the voltage and current test results of an organic solar cell with a tin oxide electron transport layer and a 5nm small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide as described in Example 1 of this invention.

[0057] Figure 2 The figure shows the external quantum efficiency and integrated short-circuit current test results of an organic solar cell with a tin oxide electron transport layer and a 5nm small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide as described in Embodiment 1 of the present invention.

[0058] Figure 3 This is a Kelvin scanning probe test image of an organic solar cell with a tin oxide electron transport layer and a 5nm small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide as described in Embodiment 1 of the present invention.

[0059] Figure 4 This is an X-ray photoelectron spectroscopy (XPS) pattern of an organic solar cell with a tin oxide electron transport layer and a 5nm small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide as described in Embodiment 1 of the present invention.

[0060] Figure 5 This is an atomic force microscopy (AFM) test result of an organic solar cell in Embodiment 1 of the present invention, in which the metal oxide electron transport layer is tin oxide and the upper electron transport layer is a 5nm small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide.

[0061] Figure 6 This is a graph showing the voltage and current test results of an organic solar cell with a tin oxide electron transport layer and a 10nm small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide as described in Example 2 of the present invention.

[0062] Figure 7 This is a graph showing the voltage and current test results of a single-layer organic solar cell with tin oxide as the metal oxide electron transport layer, as described in Comparative Example 1 of this invention.

[0063] Figure 8 The figure shows the external quantum efficiency and integral short-circuit current test results of the single-layer electron transport layer organic solar cell with tin oxide as the metal oxide electron transport layer as described in Comparative Example 1 of this invention.

[0064] Figure 9 This is a Kelvin scanning probe test image of a single-layer electron transport layer organic solar cell with tin oxide as the metal oxide electron transport layer, as described in Comparative Example 1 of this invention.

[0065] Figure 10 This is an X-ray photoelectron spectroscopy (XPS) test image of a single-layer organic solar cell with tin oxide as the electron transport layer, as described in Comparative Example 1 of this invention.

[0066] Figure 11 This is an atomic force microscopy (AFM) test result of the organic solar cell with a single-layer electron transport layer, described in Comparative Example 1 of this invention, where the metal oxide electron transport layer is tin oxide.

[0067] Figure 12 This is a graph showing the voltage and current test results of the organic solar cell described in Comparative Example 2 of this invention, which does not contain a single-layer small molecule electron transport layer.

[0068] Figure 13 This is a graph showing the voltage and current test results of an organic solar cell with a tin oxide electron transport layer and a 17nm small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide as described in Comparative Example 3 of the present invention.

[0069] Figure 14This is a graph showing the voltage and current test results of an organic solar cell with a tin oxide electron transport layer and a 30nm small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide as described in Comparative Example 4 of this invention. Detailed Implementation

[0070] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0071] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available conventional products.

[0072] Example 1

[0073] The lower electron transport layer is tin oxide, and the upper electron transport layer is a 5nm thick small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide layer organic solar cell.

[0074] (1) The indium tin oxide conductive glass (glass thickness 0.7mm, ITO thickness 135nm) is cleaned in sequence by distilled water, isopropanol, acetone and isopropanol. Each step is ultrasonically cleaned for more than 15 minutes. After cleaning, the indium tin oxide conductive glass is dried with an air gun for later use.

[0075] (2) An aqueous solution of tin oxide nanoparticles (solid content 1.5%) was spin-coated onto the upper layer of indium tin oxide conductive glass at a speed of 4000 rpm for 60 s, with a thickness of 10 nm. After spin-coating, thermal annealing was performed on a heating table at a temperature of 150 °C for 30 min.

[0076] (3) A methanol solution (0.5 mg / ml) of (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide was spin-coated onto the upper layer of tin oxide by spin coating at a speed of 3000 rpm for 30 s, with a thickness of 5 nm.

[0077] (4) Dissolve the donor material PM6 and the acceptor material Y6 in chloroform at a mass ratio of 1:1.2, with a total concentration of 13.2 mg / ml. Spin-coat the mixture onto the electron transport layer at a speed of 3000 rpm for 30 s. After spin-coating, anneal the mixture at 90℃ for 5 min.

[0078] (5) Place the substrate into the vacuum evaporation chamber and perform a vacuuming operation until the vacuum level drops to 2×10⁻⁶. -6At Pa, a layer of molybdenum oxide with a thickness of 8 nm is vacuum deposited above the photoactive layer as an electron transport layer.

[0079] (6) After completing the above steps, a layer of conductive anodic silver metal with a thickness of 100 nm is deposited on top of molybdenum oxide.

[0080] The 5nm thick tin oxide-based organic solar cell with small molecule modification achieved a photoelectric conversion efficiency of 17.06%, further improving the fill factor and photoelectric conversion efficiency of the optoelectronic device.

[0081] Example 2

[0082] The lower electron transport layer is tin oxide, and the upper electron transport layer is a 10nm thick organic solar cell with small molecules (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide.

[0083] (1) The indium tin oxide conductive glass (glass thickness 0.7mm, ITO thickness 135nm) is cleaned in sequence by distilled water, isopropanol, acetone and isopropanol. Each step is ultrasonically cleaned for more than 15 minutes. After cleaning, the indium tin oxide conductive glass is dried with an air gun for later use.

[0084] (2) An aqueous solution of tin oxide nanoparticles (solid content 1.5%) was spin-coated onto the upper layer of indium tin oxide conductive glass at a speed of 4000 rpm for 60 s, with a thickness of 10 nm. After spin-coating, thermal annealing was performed on a heating table at a temperature of 150 °C for 30 min.

[0085] (3) A methanol solution (2 mg / ml) of (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide was spin-coated onto the upper layer of tin oxide by spin coating at a speed of 2000 rpm for 30 s, with a thickness of 10 nm.

[0086] (4) Dissolve the donor material PM6 and the acceptor material Y6 in chloroform at a mass ratio of 1:1.2, with a total concentration of 13.2 mg / ml. Spin-coat the mixture onto the electron transport layer at a speed of 3000 rpm for 30 s. After spin-coating, anneal the mixture at 90℃ for 5 min.

[0087] (5) Place the substrate into the vacuum evaporation chamber and perform a vacuuming operation until the vacuum level drops to 2×10⁻⁶. -6 At Pa, a layer of molybdenum oxide with a thickness of 8 nm is vacuum deposited above the photoactive layer as an electron transport layer.

[0088] (6) After completing the above steps, a layer of conductive anodic silver metal with a thickness of 100 nm is deposited on top of molybdenum oxide.

[0089] The 10nm thick tin oxide-based organic solar cell with small molecule modification achieved a photoelectric conversion efficiency of 16.76%, further improving the fill factor and photoelectric conversion efficiency of the optoelectronic device.

[0090] Comparative Example 1

[0091] There are no cases of organic solar cells containing small molecule electron transport layers; the only electron transport layer is a single layer of tin oxide.

[0092] (1) The indium tin oxide conductive glass (glass thickness 0.7mm, ITO thickness 135nm) is cleaned in sequence by distilled water, isopropanol, acetone and isopropanol. Each step is ultrasonically cleaned for more than 15 minutes. After cleaning, the indium tin oxide conductive glass is dried with an air gun for later use.

[0093] (2) An aqueous solution of tin oxide nanoparticles (solid content 1.5%) was spin-coated onto the upper layer of indium tin oxide conductive glass at a speed of 4000 rpm for 60 s, with a thickness of 10 nm. After spin-coating, thermal annealing was performed on a heating table at a temperature of 150 °C for 30 min.

[0094] (3) Dissolve the donor material PM6 and the acceptor material Y6 in chloroform at a mass ratio of 1:1.2, with a total concentration of 13.2 mg / ml. Spin-coat the mixture onto the electron transport layer at a speed of 3000 rpm for 30 s. After spin-coating, anneal the mixture at 90℃ for 5 min.

[0095] (4) Place the substrate into the vacuum evaporation chamber and perform a vacuuming operation until the vacuum level drops to 2×10⁻⁶. -6 At Pa, a layer of molybdenum oxide with a thickness of 8 nm is vacuum deposited above the photoactive layer as an electron transport layer.

[0096] (5) After completing the above steps, a layer of conductive anodic silver metal with a thickness of 100 nm is deposited on top of molybdenum oxide.

[0097] The organic solar cell with tin oxide as the only metal oxide electron transport layer was tested and found to have a photoelectric conversion efficiency of 15.47%.

[0098] Comparative Example 2

[0099] Examples include organic solar cells containing only small molecule electron transport layers and those without single-layer small molecule electron transport layers containing metal oxide electron transport layers.

[0100] (1) The indium tin oxide conductive glass (glass thickness 0.7mm, ITO thickness 135nm) is cleaned in sequence by distilled water, isopropanol, acetone and isopropanol. Each step is ultrasonically cleaned for more than 15 minutes. After cleaning, the indium tin oxide conductive glass is dried with an air gun for later use.

[0101] (2) A methanol solution (2 mg / ml) of (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide was spin-coated onto the upper layer of indium tin oxide conductive glass at a speed of 2000 rpm for 30 s and a thickness of 10 nm.

[0102] (3) Dissolve the donor material PM6 and the acceptor material Y6 in chloroform at a mass ratio of 1:1.2, with a total concentration of 13.2 mg / ml. Spin-coat the mixture onto the electron transport layer at a speed of 3000 rpm for 30 s. After spin-coating, anneal the mixture at 90℃ for 5 min.

[0103] (4) Place the substrate into the vacuum evaporation chamber and perform a vacuuming operation until the vacuum level drops to 2×10⁻⁶. -6 At Pa, a layer of molybdenum oxide with a thickness of 8 nm is vacuum deposited above the photoactive layer as an electron transport layer.

[0104] (5) After completing the above steps, a layer of conductive anodic silver metal with a thickness of 100 nm is deposited on top of molybdenum oxide.

[0105] The organic solar cell, which uses only small molecules as a single-layer electron transport layer, achieved a photoelectric conversion efficiency of only 11.61%.

[0106] Comparative Example 3

[0107] The lower electron transport layer is tin oxide, and the upper electron transport layer is a 17nm thick small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide layer for organic solar cells.

[0108] (1) The indium tin oxide conductive glass (glass thickness 0.7mm, ITO thickness 135nm) is cleaned in sequence by distilled water, isopropanol, acetone and isopropanol. Each step is ultrasonically cleaned for more than 15 minutes. After cleaning, the indium tin oxide conductive glass is dried with an air gun for later use.

[0109] (2) An aqueous solution of tin oxide nanoparticles (solid content 1.5%) was spin-coated onto the upper layer of indium tin oxide conductive glass at a speed of 4000 rpm for 60 s, with a thickness of 10 nm. After spin-coating, thermal annealing was performed on a heating table at a temperature of 150 °C for 30 min.

[0110] (3) A methanol solution (4 mg / ml) of (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide was spin-coated onto the upper layer of tin oxide by spin coating at a speed of 2000 rpm for 30 s, resulting in a thickness of 17 nm.

[0111] (4) Dissolve the donor material PM6 and the acceptor material Y6 in chloroform at a mass ratio of 1:1.2, with a total concentration of 13.2 mg / ml. Spin-coat the mixture onto the electron transport layer at a speed of 3000 rpm for 30 s. After spin-coating, anneal the mixture at 90℃ for 5 min.

[0112] (5) Place the substrate into the vacuum evaporation chamber and perform a vacuuming operation until the vacuum level drops to 2×10⁻⁶. -6 At Pa, a layer of molybdenum oxide with a thickness of 8 nm is vacuum deposited above the photoactive layer as an electron transport layer.

[0113] (6) After completing the above steps, a layer of conductive anodic silver metal with a thickness of 100 nm is deposited on top of molybdenum oxide.

[0114] The 17nm thick tin oxide-based organic solar cell with small molecule modification achieved a photoelectric conversion efficiency of 14.60%, further improving the fill factor and photoelectric conversion efficiency of the optoelectronic device.

[0115] Comparative Example 4

[0116] The lower electron transport layer is tin oxide, and the upper electron transport layer is a 30nm thick small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide layer organic solar cell.

[0117] (1) The indium tin oxide conductive glass (glass thickness 0.7mm, ITO thickness 135nm) is cleaned in sequence by distilled water, isopropanol, acetone and isopropanol. Each step is ultrasonically cleaned for more than 15 minutes. After cleaning, the indium tin oxide conductive glass is dried with an air gun for later use.

[0118] (2) An aqueous solution of tin oxide nanoparticles (solid content 1.5%) was spin-coated onto the upper layer of indium tin oxide conductive glass at a speed of 4000 rpm for 60 s, with a thickness of 10 nm. After spin-coating, thermal annealing was performed on a heating table at a temperature of 150 °C for 30 min.

[0119] (3) A methanol solution (6 mg / ml) of (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide was spin-coated onto the upper layer of tin oxide by spin coating at a speed of 2000 rpm for 30 s, resulting in a thickness of 30 nm.

[0120] (4) Dissolve the donor material PM6 and the acceptor material Y6 in chloroform at a mass ratio of 1:1.2, with a total concentration of 13.2 mg / ml. Spin-coat the mixture onto the electron transport layer at a speed of 3000 rpm for 30 s. After spin-coating, anneal the mixture at 90℃ for 5 min.

[0121] (5) Place the substrate into the vacuum evaporation chamber and perform a vacuuming operation until the vacuum level drops to 2×10⁻⁶. -6 At Pa, a layer of molybdenum oxide with a thickness of 8 nm is vacuum deposited above the photoactive layer as an electron transport layer.

[0122] (6) After completing the above steps, a layer of conductive anodic silver metal with a thickness of 100 nm is deposited on top of molybdenum oxide.

[0123] The 30nm thick small molecule modified tin oxide-based organic solar cell achieved a photoelectric conversion efficiency of 11.20%, further improving the fill factor and photoelectric conversion efficiency of the optoelectronic device.

[0124] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A tin oxide-based organic solar cell device modified with organic small molecules, characterized in that, Its structure, from bottom to top, consists of: a transparent substrate, a conductive cathode, an electron transport layer, a photoactive layer, a hole transport layer, and a metal anode; The electron transport layer is composed of a lower tin oxide layer and an upper small molecule material (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) layer; The thickness of the upper small molecule material (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) layer is 3-10 nm.

2. The tin oxide-based organic solar cell device based on organic small molecule modification according to claim 1, characterized in that, The thickness of the tin oxide layer is 5–40 nm.

3. The tin oxide-based organic solar cell device based on organic small molecule modification according to claim 1, characterized in that, The photoactive layer is prepared by polymer donor material PM6 and acceptor molecule Y6 at a donor-to-acceptor mass ratio of 1:0.8-1.6; the thickness of the photoactive layer is 50-400 nm; and the molecular weight of the polymer donor material PM6 is 15-60 kDa.

4. The tin oxide-based organic solar cell device based on organic small molecule modification according to claim 1, characterized in that, The hole transport layer is molybdenum oxide; the thickness of the hole transport layer is 5–15 nm.

5. The tin oxide-based organic solar cell device based on organic small molecule modification according to claim 1, characterized in that, The metal anode is at least one of gold, silver, aluminum and calcium; the thickness of the metal anode is 80-120 nm.

6. The tin oxide-based organic solar cell device based on organic small molecule modification according to claim 1, characterized in that, The conductive cathode is at least one of indium tin oxide and fluorine tin oxide; the thickness of the conductive cathode is 80-180 nm; the transparent substrate is either transparent glass or polyimide film.

7. A method for preparing a tin oxide-based organic solar cell device based on organic small molecule modification as described in any one of claims 1 to 6, characterized in that, Includes the following steps: (1) A tin oxide layer was prepared on a conductive cathode by spin coating; (2) A small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) was spin-coated onto a tin oxide layer to obtain an electron transport layer; (3) The donor material PM6 and the acceptor molecule Y6 were spin-coated onto the electron transport layer by solution spin coating and then annealed to obtain the photoactive layer; (4) Prepare a hole transport layer on the photoactive layer; (5) Prepare a metal anode on the hole transport layer.

8. The method for preparing a tin oxide-based organic solar cell device based on organic small molecule modification according to claim 7, characterized in that, The tin oxide layer in step (1) is obtained by spin-coating an aqueous solution of tin oxide nanoparticles onto a conductive cathode and then annealing it; the solid content of the aqueous solution of tin oxide nanoparticles is 1.5-3%; the spin-coating speed is 2000-4000 rpm and the spin-coating time is 40-60 s; the spin-coating speed is 2000-4000 rpm and the spin-coating time is 40-60 s. Step (2) refers to spin-coating a small molecule (2-(3-1,10-phenanthroline)-6-naphthyl)diphenylphosphine oxide (Phen-NaDPO) solution onto a tin oxide layer, with a solution concentration of 0.5-2 mg / ml; the spin-coating speed is 1000-3000 rpm and the time is 30-60 s.

9. The method for preparing a tin oxide-based organic solar cell device based on organic small molecule modification according to claim 7, characterized in that, The total concentration of the solution in step (3) is 13-20 mg / ml; the spin coating speed is 2000-4000 rpm and the spin coating time is 20-60 s; the annealing temperature is 90-120℃ and the time is 3-30 minutes. The hole transport layer in step (4) is prepared by vacuum deposition; the metal anode in step (5) is prepared by vacuum deposition.

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