An optoelectronic device and its application

Abstract

The present invention belongs to the field of organic optoelectronic materials and relates to an optoelectronic device, which includes an anode, a hole transport layer, an active layer, an electron transport layer, and a cathode arranged in sequence. The active layer material is a mixture of a donor material PM6 and an acceptor material BSeC8-4F in a ratio of 1:1 to 1:1.5. The organic solar cell based on the optoelectronic device of the present invention achieves an energy conversion efficiency of 16.51%; the organic photodetector obtains a sensitivity of 0.504 A / W; the organic optoelectronic synapse can simulate human learning behavior.

Description

Technical Field

[0001] The present invention belongs to the field of organic optoelectronic materials, and in particular, to an optoelectronic device and its application. Background Art

[0002] In recent years, optoelectronic applications based on organic optoelectronic materials have developed rapidly in achieving high-efficiency organic photovoltaics (OPVs), organic photodetectors (OPDs), and organic optoelectronic synapses. With the booming development of small-molecule acceptor materials, the power conversion efficiency (PCE) of organic solar cells has been gradually improved. In this context, near-infrared organic photodetectors have been increasingly widely used in the fields of optical communication, environmental monitoring, biomedical imaging, sensing, etc. due to their advantage of adjustable detection wavelength. Moreover, in the era of artificial intelligence, using organic optoelectronic synapses to simulate the learning and memory abilities of the human brain is necessary for the development of future advanced bionic electronic devices and bionic robots.

[0003] Currently, under the background of material design and device optimization, organic optoelectronic applications have experienced booming development. Integrating multiple applications into one device to achieve multifunctional applications is of great significance for reducing circuit space. In current research, researchers have integrated OPV and OPD in one device to simultaneously achieve energy conversion and light detection. So far, A-D-A type non-fullerene acceptor (NFA) materials with absorption wavelengths above 1000 nm have realized dual-functional devices for OPV and OPD, with a PCE of 10.70% and a sensitivity (R) of 0.55 A / W (900 nm) for the OPD. However, the PCE of the dual-functional device is relatively low, approximately 10%, and there is still much room for improvement. For multifunctional devices, improving the energy conversion efficiency of organic solar cells, maintaining a high R value for light detection, and realizing simulated learning of organic optoelectronic synapses have not been achieved yet. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an optoelectronic device involving small-molecule acceptor materials, and to develop its applications in organic solar cells, organic photodetectors, and organic optoelectronic synapses by utilizing the characteristics of small-molecule acceptor materials in the near-infrared light region.

[0005] The technical solution for achieving the purpose of the present invention is as follows:

[0006] An optoelectronic device includes an anode, a hole transport layer, an active layer, an electron transport layer, and a cathode which are sequentially arranged. The active layer material is a mixture of a donor material poly[1-(5-(4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)-6-methylbenzo[1,2-b:4,5-b']dithiophen-2-yl)thiophen-2-yl)-5,7-bis(2-ethylhexyl)-3-(5-methylthiophen-2-yl)-4H,8H-benzo[1,2-c:4,5-c']dithiophene-4,8-dione] (PM6) and an acceptor material 2,2'-((2Z,2'Z)-(12,13-di)(3-ethylhexyl)-3,9-di,octyl-12,13-dihydro-[1,2,5]selenadiazolo[3,4-e]thieno[2,“3”:4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno[3,2-b]indole-2,10-diacyl)bis(formylsulfoxide)bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-2,1-diylidene) (BSeC8-4F) obtained by mixing in a ratio of 1:1 to 1:1.5.

[0007] The structure of the above-mentioned PM6 (D-A copolymer) is as follows:

[0008]

[0009] The above-mentioned BSeC8-4F is a narrow-band small molecule acceptor material, and its structure is as follows:

[0010]

[0011] Introducing a selenocyclic ring into the A-DA’D-A structure has a good absorption spectrum in the near-infrared region.

[0012] Due to the introduction of Se atoms, the absorption spectrum of BSeC8-4F is redshifted. The combination of PM6 and BSeC8-4F can absorb the light energy in the entire visible light region and near-infrared light region, which is beneficial to generating more excitons. At the same time, due to the matching of their energy level positions, it is beneficial to the separation and transport of excitons. Moreover, they have balanced carrier transport capabilities, which is beneficial to the improvement of the fill factor in organic solar cells. Compared with the 10% energy conversion efficiency in current multifunctional devices, the combination of PM6 and BSeC8-4F is expected to achieve a significant improvement. In short, the organic solar cells prepared by the combination of PM6 and BSeC8-4F are beneficial to achieving a higher energy conversion efficiency, and the prepared organic photodetectors are beneficial to maintaining better sensitivity and further expanding their applications in organic optoelectronic synapses.

[0013] Among them, the anode material is selected from any one or a combination of indium tin oxide (ITO) glass, fluorine-doped tin dioxide glass, aluminum-doped zinc oxide glass, ITO-polyethylene terephthalate, and ITO-polyethylene naphthalate;

[0014] Among them, the hole transport material is an organic conjugated polymer, selected from poly(3,4-ethylenedioxythiophene) or polystyrene sulfonate or a combination thereof;

[0015] Among them, the electron transport layer is selected from any one or a combination of zinc oxide (ZnO), titanium dioxide (TiO2), and amine-functionalized perylene diimide (PDINN);

[0016] Among them, the cathode material is selected from common conductive materials or inert electrode materials, including silver, iron, copper, aluminum, gold, platinum, or graphite.

[0017] The thicknesses of the hole transport layer, active layer, electron transport layer, and cathode are 15±10 nm, 100±10 nm, 15±10 nm, and 100±10 nm, respectively.

[0018] The optoelectronic device of the present invention is a vertical structure device prepared by spin coating and can be applied in organic solar cells, organic photodetectors, and organic optoelectronic synapses.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] The active layer material of the present invention is a mixture of the donor material PM6 and the acceptor material BSeC8-4F in a ratio of 1:1 to 1:1.5, and when applied to an organic solar cell, the organic solar cell achieves an energy conversion efficiency of 16.51%; when applied to an organic photodetector, a sensitivity of 0.504 A / W is obtained at a near-infrared light of 830 nm; when applied to an organic optoelectronic synapse, it can simulate the learning behavior of the human brain. Description of the Drawings

[0021] Figure 1 It is the UV absorption spectrum diagram of the active layer in the optoelectronic device of the present invention;

[0022] Figure 2 It is the I-V characteristic curve diagram of the optoelectronic device of the present invention in an organic solar cell;

[0023] Figure 3 It is the diagram of the sensitivity of the organic photodetector based on the present optoelectronic device varying with the light wavelength;

[0024] Figure 4This is the application diagram of the optoelectronic device of the present invention in an organic optoelectronic synapse, where (a) is the diagram of synaptic signals varying with time, and (b) is the variation of the time taken for the postsynaptic current to reach the threshold value with the number of stimuli. Detailed implementation mode

[0025] The technical solution of the present invention will be further described in detail below through the accompanying drawings and embodiments, specifically including device preparation, material characterization, and explanation of device performance.

[0026] Example 1

[0027] An optoelectronic device, with ITO glass as the anode, PEDOT:PSS as the hole transport layer, PDINN as the electron transport layer, Ag as the cathode, and the active layer material being a mixture of the donor material PM6 and the acceptor material BSeC8-4F in a ratio of 1:1.5.

[0028] Preparation method: A number of ITO glasses with a sheet resistance of about 20 ohms per square and a specification of 15 mm × 15 mm square pieces. The cleaned ITO glasses are dried under a nitrogen gun and irradiated under a UVO ultraviolet ozone lamp for 20 minutes. The hole transport layer PEDOT:PSS (Clevios PVPAl 4083) is spin-coated for 20 s at a rotation speed of 3000 rpm and annealed on a heating platform at 150 °C for 15 minutes, and then transferred to a glove box for standby. The donor material PM6 and the acceptor material BSeC8-4F are dissolved in chloroform solvent and spin-coated on the hole transport layer. After the film is annealed at 110 °C for 10 minutes, a methanol solution of the electron transport layer material (PDINN, 1 mg / mL) is spin-coated on the active layer under the condition of 3000 rpm. Finally, an Ag electrode is deposited by vacuum evaporation as the cathode.

[0029] Figure 1 This is the UV absorption spectrum of the active layer in the optoelectronic device. The donor material PM6 mainly absorbs visible light at 420 - 700 nm, and the peak and shoulder peaks are 623 nm and 583 nm respectively. The acceptor material BSeC8-4F has a relatively wide absorption in the range of 570 nm - 1060 nm and has a strong absorption peak at 850 nm. Therefore, the active layer of the present invention has a complementary absorption range.

[0030] From Figure 2 it can be seen that the energy conversion efficiency of the organic solar cell based on this optoelectronic device is 16.51%, the open-circuit voltage (V OC ) is 0.826 V, and the short-circuit current density (J SC ) is 27.50 mA·cm -2, the fill factor (FF) is 72.69%. As shown in Table 1, compared with other multifunctional devices, the energy conversion efficiency of the organic solar cell based on the combination of PM6 and BSeC8-4F has been greatly improved.

[0031] Table 1 Photovoltaic performance parameters of the optoelectronic device based on this and its comparison with other multifunctional devices

[0032]

[0033] Figure 3 It is a graph showing the variation of the sensitivity of the organic photodetector based on the optoelectronic device with the light wavelength. As the wavelength changes, the sensitivity of the organic photodetector peaks at 830 nm and is 0.504 A / W.

[0034] Figure 4 It can reflect the learning behavior of the organic optoelectronic synapse based on the optoelectronic device. With continuous stimulation, the postsynaptic current (EPSC) of the organic optoelectronic synapse continuously increases. During the pulsed light stimulation, the time taken for the postsynaptic current to reach 2.78 mA decreases from the first time (4.30 s) to the tenth time (0.30 s). After continuous stimulation, the device has a memory effect, similar to the learning behavior of the human brain.

[0035] Therefore, the optoelectronic device based on this can be applied to the directions of organic solar cells, organic photodetectors, and organic optoelectronic synapses.

[0036] 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 other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. Application of an optoelectronic device in the field of simulating human learning behavior by an organic optoelectronic synapse, characterized in that, The optoelectronic device includes an anode, a hole transport layer, an active layer, an electron transport layer, and a cathode arranged in sequence, and is characterized in that: the active layer material is obtained by mixing a donor material PM6 and an acceptor material BSeC8-4F. The BSeC8-4F is a narrow-band small molecule acceptor material, and its structure is as follows: 。 2. The application according to claim 1, characterized in that: The material of the anode is any one or a combination of indium tin oxide glass, fluorine-doped tin dioxide glass, aluminum-doped zinc oxide glass, indium tin oxide-polyethylene terephthalate, and indium tin oxide-polyethylene naphthalate.

3. The application according to claim 1, wherein: The material of the hole transport layer is poly(3,4-ethylenedioxythiophene) or polystyrene sulfonate or a combination thereof.

4. The application according to claim 1, characterized in that: The material of the electron transport layer is any one or a combination of zinc oxide, titanium dioxide, and amine-functionalized perylene diimide.

5. The application according to claim 1, characterized in that: The material of the cathode is silver, iron, copper, aluminum, gold, platinum, or graphite.

6. The application according to claim 1, wherein: The thicknesses of the hole transport layer, the active layer, the electron transport layer, and the cathode are 15±10 nm, 100±10 nm, 15±10 nm, and 100±10 nm, respectively.

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