A cadmium-free electron transport layer, antimony-based chalcogen thin film solar cell and preparation method

Abstract

The application discloses a cadmium-free electron transport layer, an antimony-based chalcogen thin film solar cell and a preparation method, and relates to the field of solar cells. The preparation method of the cadmium-free electron transport layer comprises the following steps: S1, performing cyclic deposition of m single molecular layers of ZnO by an atomic layer deposition method to obtain a first thin film layer; S2, performing cyclic deposition of n single molecular layers of SnO2 on the first thin film layer by the atomic layer deposition method to obtain a second thin film layer; and S3, repeating steps S1 to S2 for several times to obtain the cadmium-free electron transport layer; wherein m:n=(1-6):1, the heterojunction band arrangement formed by the cadmium-free electron transport layer and an antimony-based chalcogen semiconductor presents an ideal "spike-shaped" configuration, and a corresponding conduction band step value is between 0 and 0.4 eV. The cadmium-free electron transport layer can not only effectively inhibit the aggregation and recombination of photo-generated carriers on the interface, but also ensure efficient carrier separation and transportation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solar cells, in particular to a cadmium-free electron transport layer, a Sb-based chalcogenide thin film solar cell and a preparation method. BACKGROUND

[0002] Thin film solar cells have become a research hotspot among a variety of photovoltaic cell materials due to low material consumption, high output power, high product scalability and flexibility. At present, the long-term large-area development of mainstream high-efficiency representative thin film solar cells such as copper indium gallium selenide, cadmium telluride and perovskite is still limited by the natural scarcity, environmental friendliness and long-term stability of raw materials. Based on this, in recent years, Sb-based chalcogenide thin film photovoltaic semiconductors (such as Sb2S3, Sb2Se3 and Sb2(S, Se)3) with ideal band gap, high absorption coefficient, good carrier mobility and long carrier lifetime have gradually attracted people's attention, and the corresponding cell efficiency has steadily improved.

[0003] At present, the high-efficiency Sb-based chalcogenide thin film solar cells reported mainly use cadmium sulfide (CdS) as a buffer layer, which acts as an electron transport layer (ETL). However, the CdS electron transport layer has three major defects: first, CdS contains toxic cadmium elements, which poses safety and environmental hazards during device preparation and use; second, the band gap of CdS is relatively low, at 2.4 eV, which will absorb some high-energy photons (400-600 nm) and cause parasitic current loss; third, during the preparation of CdS, cadmium ions and sulfur ions randomly diffuse into the light absorption layer under heat / light treatment, which may cause device efficiency degradation. At present, cadmium-free, wide-bandgap TiO2 and ZnO candidate electron transport layer materials have shown certain application value in Sb-based chalcogenide thin film solar cells, but there is generally an undesirable "cliff-like" or excessive "spike-like" conduction band step between the Sb-based chalcogenide light absorption layer and the TiO2, ZnO and other electron transport layers. This non-ideal heterojunction band matching seriously hinders the separation and transport of photo-generated carriers, thereby affecting the further improvement of device performance.

[0004] Therefore, the selection of an environmentally friendly and efficient stable cadmium-free electron transport layer material suitable for Sb-based chalcogenide thin film solar cells and the corresponding regulation of heterojunction interface band matching and other key scientific issues need to be addressed.

[0005] Therefore, the prior art still needs to be improved and developed. SUMMARY

[0006] Based on the deficiencies of the prior art, the purpose of the present application is to provide a cadmium-free electron transport layer, a Sb-based sulfide thin film solar cell and a preparation method, aiming to provide a cadmium-free electron transport layer suitable for a Sb-based sulfide thin film solar cell, so as to solve the problem that the non-ideal heterojunction band matching of the existing TiO2, ZnO and other electron transport layers and the Sb-based sulfide semiconductor hinders the separation and transmission of photo-generated carriers.

[0007] The technical scheme of the present application is as follows:

[0008] In the first aspect of the present application, a preparation method of a cadmium-free electron transport layer is provided, comprising the following steps:

[0009] S1, by atomic layer deposition, m times of cyclic deposition of ZnO monolayer is carried out to obtain a first thin film layer;

[0010] S2, by atomic layer deposition, n times of cyclic deposition of SnO2 monolayer is carried out on the first thin film layer to obtain a second thin film layer;

[0011] S3, steps S1 to S2 are repeated for several times to obtain the cadmium-free electron transport layer;

[0012] Wherein, m:n=(1-6):1.

[0013] Optionally, in step S1, the steps of m times of cyclic deposition of ZnO monolayer each include:

[0014] The temperature of the reaction chamber is set to 100-150 DEG C, then 40-80 ms of zinc precursor source pulse, 80-120 ms of first oxygen precursor source pulse and 5-10 s of inert gas purging are sequentially carried out in the reaction chamber.

[0015] Optionally, in step S2, the steps of n times of cyclic deposition of SnO2 monolayer each include:

[0016] The temperature of the reaction chamber is set to 100-150 DEG C, then 40-80 ms of tin precursor source pulse, 80-120 ms of second oxygen precursor source pulse and 5-10 s of inert gas purging are sequentially carried out in the reaction chamber.

[0017] Optionally, the zinc precursor source includes at least one of diethyl zinc and zinc chloride, and the first oxygen precursor source includes at least one of deionized water and ozone;

[0018] The tin precursor source includes at least one of tetra(dimethylamino)tin and tetraethyltin, and the second oxygen precursor source includes at least one of deionized water and ozone.

[0019] Optionally, in step S3, the number of times is 30-50.

[0020] In a second aspect of the present application, a cadmium-free electron transport layer is provided, wherein the cadmium-free electron transport layer is prepared by the preparation method of the present application.

[0021] In a third aspect of the present application, a Sb-based chalcogenide thin film solar cell is provided, which comprises a substrate, a Sb-based chalcogenide semiconductor light absorption layer, an electron transport layer and a window layer which are sequentially arranged on the substrate, and a first electrode and a second electrode which are respectively arranged on the window layer and the substrate; the electron transport layer is the cadmium-free electron transport layer of the present application.

[0022] Optionally, the Sb-based chalcogenide semiconductor light absorption layer comprises Sb2(Se x S 1-x )3, 0≤x≤1; the Sb-based chalcogenide thin film solar cell further comprises a Sb2O3 passivation layer arranged between the Sb-based chalcogenide semiconductor light absorption layer and the electron transport layer.

[0023] The window layer comprises one of an indium tin oxide window layer, a fluorine-doped tin oxide window layer and an aluminum-doped zinc oxide window layer.

[0024] The materials of the first electrode and the second electrode are each independently at least one of silver, aluminum, copper and nickel.

[0025] In a fourth aspect of the present application, a preparation method of the Sb-based chalcogenide thin film solar cell of the present application is provided, which comprises the following steps:

[0026] providing a substrate;

[0027] forming a Sb-based chalcogenide semiconductor light absorption layer on the substrate;

[0028] forming a cadmium-free electron transport layer on the Sb-based chalcogenide semiconductor light absorption layer by the preparation method of the present application;

[0029] forming a window layer on the cadmium-free electron transport layer;

[0030] forming a first electrode and a second electrode on the window layer and the substrate, respectively.

[0031] Optionally, the step of forming the Sb-based chalcogenide semiconductor light absorption layer on the substrate specifically comprises:

[0032] forming a Sb precursor film on the substrate by a magnetron sputtering method;

[0033] then performing a selenization treatment and / or a sulfurization treatment on the Sb precursor film to generate a Sb2(Se xS 1-x )3, 0≤x≤1, and further obtaining the antimony-based sulfur semiconductor light absorption layer.

[0034] Beneficial effects: The heterojunction band arrangement formed by the cadmium-free electron transport layer and the antimony-based sulfur semiconductor provided by the present application presents an ideal "spike-shaped" configuration, and the corresponding conduction band step value is between 0 and 0.4 eV. Not only can the accumulation and recombination of photo-generated carriers on the interface be effectively inhibited, but also the efficient carrier separation and transport can be ensured, so that the performance of the corresponding device can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a pulse program schematic diagram for atom layer deposition of the cadmium-free electron transport layer in the embodiment of the present application.

[0036] Figure 2 It is a schematic diagram of the process of atom layer deposition of the ZnO monolayer and the SnO2 monolayer in the embodiment of the present application.

[0037] Figure 3 It is a structure schematic diagram of the antimony-based sulfur thin film solar cell in the embodiment of the present application.

[0038] Figure 4 It is a current density-voltage curve diagram of the antimony-based sulfur thin film solar cell in the embodiment 1 and the comparative example 1 of the present application. DETAILED DESCRIPTION

[0039] The present application provides a cadmium-free electron transport layer, an antimony-based sulfur thin film solar cell and a preparation method. In order to make the purpose, technical scheme and effect of the present application more clear and explicit, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0041] The embodiment of the present application provides a preparation method of a cadmium-free electron transport layer, wherein, as shown in the formula (I), the preparation method comprises the following steps: Figure 1

[0042] S1, by atom layer deposition, m times of cycle deposition of ZnO monolayer is carried out to obtain a first thin film layer;

[0043] S2, by atom layer deposition, n times of cycle deposition of SnO2 monolayer is carried out on the first thin film layer to obtain a second thin film layer;

[0044] ​S3. Repeat steps S1 to S2 several times to obtain the cadmium-free electron transport layer.

[0045] Where m:n=(1~6):1.

[0046] In other words, the atomic layer deposition process in this invention includes several cycles, such as... Figure 1 As shown, each cycle includes m cycles of ZnO monolayer deposition (forming the first thin film layer, i.e., the ZnO thin film layer) and n cycles of SnO2 monolayer deposition (forming the second thin film layer, i.e., the SnO2 thin film layer). Therefore, the cadmium-free electron transport layer (which can be referred to as the ZTO layer) prepared by the above method includes several alternating layers of the first thin film layer (ZnO thin film layer) and the second thin film layer (SnO2 thin film layer), wherein the first thin film layer includes m stacked ZnO monolayers and the second thin film layer includes n stacked SnO2 monolayers, and the ratio of m to n is (1~6):1, that is, the ratio of the number of Zn atoms to Sn atoms in the electron transport layer (i.e., the ZTO layer) is (1~6):1. This invention regulates the band structure (i.e., band gap, conduction band, and valence band positions) of the ZTO layer by adjusting the ratio of Zn atoms to Sn atoms. When the ratio of Zn atoms to Sn atoms is (1-6):1, the heterojunction formed with the antimony-based chalcogenide semiconductor exhibits an ideal "peak-shaped" band arrangement, corresponding to a conduction band order value between 0 and 0.4 eV. Further, as an example, the ratio of m to n can be 1:1, 2:1, 3:1, 4:1, 5:1, or 6:1, etc.

[0047] The cadmium-free electron transport layer prepared by atomic layer deposition technology in this invention possesses high quality, a suitable band gap, and excellent optoelectronic properties. The heterojunction energy band arrangement formed by the cadmium-free electron transport layer and the antimony-based chalcogenide semiconductor exhibits an ideal "peak-shaped" configuration, with a corresponding conduction band order value between 0 and 0.4 eV. This not only effectively suppresses the aggregation and recombination of photogenerated carriers at the interface but also ensures efficient carrier separation and transport, thereby improving the performance of the corresponding device. In step S1, in some embodiments, in m cycles of ZnO monolayer deposition, each ZnO monolayer deposition step specifically includes:

[0048] The temperature of the zinc precursor source and the first oxygen precursor source is set to room temperature, the temperature of the reaction chamber is set to 100-150°C (for example, it can be 100°C, 110°C, 120°C, 130°C, 140°C or 150°C, etc.), and then the zinc precursor source pulse of 40-80 milliseconds (for example, it can be 40 milliseconds, 50 milliseconds, 60 milliseconds, 70 milliseconds or 80 milliseconds, etc.), the first oxygen precursor source pulse of 80-120 milliseconds (for example, it can be 80 milliseconds, 90 milliseconds, 100 milliseconds, 110 milliseconds or 120 milliseconds, etc.) and the inert gas (such as N2) purge of 5-10 seconds (for example, it can be 5 seconds, 6 seconds, 7 seconds, 8 seconds, 9 seconds or 10 seconds, etc.) are sequentially performed.

[0049] In step S2, in some embodiments, the step of depositing each SnO2 monolayer in the n cycles of SnO2 monolayer deposition specifically includes:

[0050] The temperature of the tin precursor source is set to 50-80°C (for example, it can be 50°C, 60°C, 70°C or 80°C, etc.), the temperature of the second oxygen precursor source is set to room temperature, the temperature of the reaction chamber is set to 100-150°C (for example, it can be 100°C, 110°C, 120°C, 130°C, 140°C or 150°C, etc.), and then the tin precursor source pulse of 40-80 milliseconds (for example, it can be 40 milliseconds, 50 milliseconds, 60 milliseconds, 70 milliseconds or 80 milliseconds, etc.), the second oxygen precursor source pulse of 80-120 milliseconds (for example, it can be 80 milliseconds, 90 milliseconds, 100 milliseconds, 110 milliseconds or 120 milliseconds, etc.) and the inert gas (such as N2) purge of 5-10 seconds (for example, it can be 5 seconds, 6 seconds, 7 seconds, 8 seconds, 9 seconds or 10 seconds, etc.) are sequentially performed.

[0051] In the above-mentioned processes of ZnO monolayer deposition and SnO2 monolayer deposition, the temperature of each precursor source delivery pipe (zinc precursor source delivery pipe, first oxygen precursor source delivery pipe, tin precursor source delivery pipe and second oxygen precursor source delivery pipe, when the first oxygen precursor source and the second oxygen precursor source are the same substance, the same delivery pipe is used) is 80-120°C, for example, it can be 80°C, 90°C, 100°C, 110°C or 120°C, etc.

[0052] In some embodiments, the zinc precursor source includes at least one of diethyl zinc (DEZ) and zinc chloride (ZnCl2), but is not limited thereto.

[0053] In some embodiments, the first oxygen precursor source includes at least one of deionized water (H2O) and ozone, but is not limited thereto.

[0054] In some embodiments, the tin precursor source includes at least one of tetra(dimethylamino)tin (TDMASn) and tetraethyltin, but is not limited thereto.

[0055] In some embodiments, the second oxygen precursor source includes at least one of deionized water (H2O) and ozone, but is not limited thereto.

[0056] In step S3, in some embodiments, the number of times is 30 to 50 times, for example, 30 times, 35 times, 40 times, 45 times or 50 times, etc.

[0057] The following example, using DEZ as the zinc precursor source, TDMASn as the tin precursor source, and H2O as the first and second oxygen precursor sources, illustrates the deposition principle through atomic layer deposition (ALD) of one ZnO monolayer deposition and one SnO2 monolayer deposition. Figure 2 As shown, a DEZ pulse is introduced into the reaction chamber, and DEZ molecules are chemically adsorbed onto the substrate surface (a layer of DEZ molecules adsorbed onto the substrate surface may lose one or more CH2 or other atoms). Then, an H2O pulse is introduced, and H2O reacts with DEZ molecules to form a monolayer of ZnO. Then, N2 is purged. Next, a TDMASn pulse is introduced, and TDMASn molecules are adsorbed onto the surface of the ZnO monolayer. Then, an H2O pulse is introduced, and H2O reacts with TDMASn molecules to form a monolayer of SnO2.

[0058] This invention also provides a cadmium-free electron transport layer, wherein the cadmium-free electron transport layer is prepared using the preparation method described above in this invention. Specifically, the cadmium-free electron transport layer includes a plurality of alternatingly stacked first thin film layers and second thin film layers. The first thin film layer includes m stacked ZnO monolayers, and the second thin film layer includes n stacked SnO2 monolayers, wherein the ratio of m to n is (1-6):1.

[0059] In this embodiment of the invention, the heterojunction energy band arrangement formed by the cadmium-free electron transport layer and the antimony-based chalcogenide semiconductor presents an ideal "peak-shaped" configuration, with the corresponding conduction band order value between 0 and 0.4 eV. This not only effectively suppresses the aggregation and recombination of photogenerated carriers at the interface, but also ensures efficient carrier separation and transport, thereby improving the performance of the corresponding device.

[0060] In some embodiments, the number of the first thin film layer is the same as the number of the second thin film layer, wherein the number of the first thin film layer is 30 to 50 and the number of the second thin film layer is 30 to 50.

[0061] This invention also provides an antimony-based chalcogenide thin-film solar cell (specifically, a cadmium-free substrate structure antimony-based chalcogenide thin-film solar cell), wherein, as... Figure 3As shown, the antimony-based sulfide thin-film solar cell comprises a substrate 1, an antimony-based sulfide semiconductor light-absorbing layer 2, an electron transport layer 3 and a window layer 4 sequentially on the substrate 1, and a first electrode 51 and a second electrode 52 on the window layer and the substrate, respectively. The electron transport layer is a cadmium-free electron transport layer as described above. That is, the antimony-based sulfide thin-film solar cell comprises a substrate 1, an antimony-based sulfide semiconductor light-absorbing layer 2, an electron transport layer 3 and a window layer 4 sequentially stacked, and a first electrode 51 and a second electrode 52 on the window layer and the substrate, respectively. The antimony-based sulfide thin-film solar cell provided by the present application has an ideal "spike-like" configuration of heterojunction band arrangement between the antimony-based sulfide semiconductor light-absorbing layer and the cadmium-free electron transport layer, and the corresponding conduction band offset value is between 0-0.4 eV, which not only effectively suppresses the accumulation and recombination of photo-generated carriers at the interface, but also ensures efficient carrier separation and transport. The cadmium-free antimony-based sulfide thin-film solar cell can achieve an energy conversion efficiency of 8.77%, and the open-circuit voltage, short-circuit current density and fill factor are 31.78 mA / cm 2 , 438 mV and 63.08%, respectively.

[0062] In some embodiments, the substrate is a glass substrate plated with a metal (such as molybdenum, etc.) on the surface, but is not limited thereto.

[0063] In some embodiments, the antimony-based sulfide semiconductor light-absorbing layer comprises Sb2(Se x S 1-x )3, 0≤x≤1. For example, the antimony-based sulfide semiconductor light-absorbing layer comprises Sb2Se3, Sb2(Se 0.9 S 0.1 )3, Sb2(Se 0.8 S 0.2 )3, Sb2(Se 0.7 S 0.3 )3, Sb2(Se 0.6 S 0.4 )3, Sb2(Se 0.5 S 0.5 )3, Sb2(Se 0.4 S 0.6 )3, Sb2(Se 0.3 S 0.7 )3, Sb2(Se 0.2 S 0.8 )3, Sb2(Se 0.1 S 0.9 )3 or Sb2S3, etc.

[0064] In some embodiments, the antimony-based chalcogenide thin-film solar cell further comprises a Sb2O3 passivation layer between the antimony-based chalcogenide semiconductor light-absorbing layer and the electron transport layer. The Sb2O3 passivation layer can inhibit non-radiative recombination in the light-absorbing layer bulk, improve carrier lifetime, extraction efficiency and collection efficiency.

[0065] In some embodiments, the window layer comprises one of an indium tin oxide (ITO) window layer, a fluorine-doped tin oxide (FTO) window layer, an aluminum-doped zinc oxide (AZO) window layer, but is not limited thereto.

[0066] In some embodiments, the material of the first electrode and the second electrode is each independently at least one of silver, aluminum, copper and nickel, but is not limited thereto.

[0067] The present application also provides a preparation method of the antimony-based chalcogenide thin-film solar cell as described above, comprising the following steps:

[0068] S11, providing a substrate;

[0069] S12, forming an antimony-based chalcogenide semiconductor light-absorbing layer on the substrate;

[0070] S13, forming a cadmium-free electron transport layer on the antimony-based chalcogenide semiconductor light-absorbing layer by the preparation method as described above;

[0071] S14, forming a window layer on the cadmium-free electron transport layer;

[0072] S15, forming a first electrode and a second electrode on the window layer and the substrate, respectively.

[0073] The present application grows a high-quality, suitable band gap and excellent photoelectric performance cadmium-free electron transport layer on the antimony-based chalcogenide semiconductor light-absorbing layer, simultaneously optimizes the heterojunction interface band matching and carrier dynamics, and finally realizes the overall improvement of the key performance of the device through synergistic regulation.

[0074] In step S11, the selection of the substrate is described above and will not be repeated here.

[0075] In some embodiments, the step of forming an antimony-based chalcogenide semiconductor light-absorbing layer on the substrate specifically comprises:

[0076] S121, forming a Sb precursor thin film on the substrate by a radio frequency magnetron sputtering method;

[0077] S122, then performing a seleniumization treatment and / or a sulfurization treatment on the Sb precursor thin film to generate a Sb2(Se x S 1-x)3, 0≤x≤1, and further obtaining the antimony-based chalcogenide semiconductor light absorption layer.

[0078] The antimony-based chalcogenide semiconductor light absorption layer is prepared by a radio frequency magnetron sputtering combined with a selenization and / or sulfurization process.

[0079] In some embodiments, the step S121 specifically comprises:

[0080] Sb as a target material, under a power of 10-50 W (for example, 10 W, 20 W, 30 W, 40 W or 50 W, etc.) and a working pressure of 0.5-2 Pa (for example, 0.5 Pa, 1 Pa, 1.5 Pa or 2 Pa, etc.), radio frequency magnetron sputtering deposition on the substrate for 25-50 min (for example, 25 min, 30 min, 35 min, 40 min, 45 min or 50 min, etc.) to obtain a Sb precursor film;

[0081] In some embodiments, the step S122 specifically comprises:

[0082] The substrate with the Sb precursor film on the surface, Se particles and / or S powder are placed in a quartz tube, and selenization treatment and / or sulfurization treatment is performed at a temperature of 400-500°C (for example, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C or 500°C, etc.) for 20-40 min (for example, 20 min, 25 min, 30 min, 35 min or 40 min, etc.) to generate Sb2(Se x S 1-x )3.

[0083] In some specific embodiments, the step S122 specifically comprises the following steps:

[0084] The substrate with the Sb precursor film on the surface is placed in the middle temperature zone of a three-temperature-zone vacuum quartz tube, Se particles and S powder are respectively placed in the left and right temperature zones of the three-temperature-zone vacuum quartz tube (or Se particles are placed in the right temperature zone of the three-temperature-zone vacuum quartz tube, and the right temperature zone is not placed with any substance; or S powder is respectively placed in the right temperature zone of the three-temperature-zone vacuum quartz tube, and the left temperature zone is not placed with any substance), inert gas (such as argon, to remove residual impurity gas) is introduced, the temperature of the three-temperature-zone vacuum quartz tube is set to 400-500°C, the treatment time is 20-40 min (i.e., the treatment time is 20-40 min at a temperature of 400-500°C), and the working pressure in the three-temperature-zone vacuum quartz tube is maintained at 0.5-3 mTorr (for example, 0.5 mTorr, 1 mTorr, 1.5 mTorr, 2 mTorr, 2.5 mTorr or 3 mTorr, etc.), to generate Sb2(Se x S1-x )3.

[0085] In step S13, when the cadmium-free electron transport layer is formed on the antimony-based chalcogenide semiconductor light absorption layer by using the preparation method as described above in the embodiments of the present application, due to the presence of a suitable temperature and an oxygen source during the atomic layer deposition process and the presence of Sb dangling bonds on the surface of the antimony-based chalcogenide semiconductor light absorption layer, an ultrathin Sb2O3 passivation layer is formed on the surface of the antimony-based chalcogenide semiconductor light absorption layer (the Sb dangling bonds on the surface of the antimony-based chalcogenide semiconductor light absorption layer react with the oxygen source diffused to the surface of the antimony-based chalcogenide semiconductor light absorption layer to form Sb2O3, and the formation of the Sb2O3 passivation layer is indirectly proved by the increase of the oxygen vacancy concentration characterized by X-ray photoelectron spectroscopy in the present application), which can inhibit the non-radiative recombination in the light absorption layer, improve the carrier lifetime, extraction efficiency and collection efficiency.

[0086] In step S14, the preparation method of the window layer is not limited in the present application, and for example, the magnetron sputtering method can be selected for preparation.

[0087] In step S15, the preparation method of the first electrode and the second electrode is not limited in the present application, and for example, the first electrode and the second electrode can be prepared by the thermal evaporation method.

[0088] The present application will be further described by specific examples.

[0089] Example 1

[0090] The present embodiment provides a preparation method of an antimony-based chalcogenide thin-film solar cell, comprising the following steps:

[0091] A Sb precursor thin film is formed on a molybdenum-coated glass substrate by using radio frequency magnetron sputtering (a magnetron sputtering device is purchased from Shenyang Pengcheng Vacuum Technology Co., Ltd., and the model is TCDP-Ⅱ) with Sb as the target material at a power of 30 W and an operating pressure of 1.0 Pa for 25 min (the side of the glass substrate containing molybdenum is attached to the Sb precursor thin film);

[0092] The molybdenum-coated glass substrate with the Sb precursor thin film on the surface is placed in the middle temperature zone of a three-zone vacuum quartz tube, two quartz boats containing Se particles (0.2 g) and S powder (0.05 g) respectively are placed in the left and right temperature zones, high-purity argon is introduced into the tube to remove residual impurity gases, and the gas pressure in the quartz tube is maintained at 30 KPa. Then, the temperature is gradually increased to 415 ℃ at a rate of 20 ℃ per minute, and the sulfidation and selenization treatment is performed at 415 ℃ for 35 min, so that Se and S react with the Sb precursor to generate Sb2(Se x S 1-x)3, x = 0.8, and the working pressure was kept at 2.5 mTorr; after cooling, the Sb-based chalcogenide semiconductor light-absorbing layer with a thickness of 220 nm was obtained.

[0093] A ZTO layer, i.e. a cadmium-free electron transport layer, with a Zn and Sn atomic number ratio of 4:1 was deposited on the Sb-based chalcogenide semiconductor light-absorbing layer by an atomic layer deposition process (an atomic layer deposition device was purchased from Dongguan Nafion Microelectronics Equipment Co., Ltd., model NCE-200R). In this process, diethyl zinc (DEZ), tetra(dimethylamino)tin (TDMASn) and H2O were used as zinc precursor source, tin precursor source and oxygen precursor source, respectively. The temperature of DEZ and H2O was kept at room temperature, while the temperature of the stainless steel container storing TDMASn was set to 65°C, and the temperature of the delivery tube (delivery tube of each precursor source) and the reaction chamber was set to 100°C and 120°C, respectively. The atomic layer deposition program included 50 cycles, each cycle including 4 cycles of ZnO monolayer deposition and 1 cycle of SnO2 monolayer deposition. In each cycle of ZnO monolayer deposition, the process parameters were as follows: 50 ms of DEZ pulse, 80 ms of H2O pulse and 5 s of N2purging; in each cycle of SnO2 monolayer deposition, the process parameters were as follows: 50 ms of TDMASn pulse, 80 ms of H2O pulse and 5 s of N2purging. After 50 cycles, the cadmium-free electron transport layer was formed.

[0094] The ITO window layer with a thickness of 400 nm was formed on the cadmium-free electron transport layer by magnetron sputtering deposition under the conditions of a pressure of 0.35 Pa and a power of 120 W.

[0095] The first electrode (silver electrode) and the second electrode (silver electrode) with a thickness of 80 nm were respectively formed on the ITO window layer and the molybdenum-coated glass substrate by thermal evaporation to obtain the Sb-based chalcogenide thin-film solar cell.

[0096] Comparative Example 1

[0097] The Sb-based chalcogenide thin-film solar cell of the present example is different from that of Example 1 only in that a CdS electron transport layer is used instead of the cadmium-free electron transport layer. The current density-voltage curve of the Sb-based chalcogenide thin-film solar cell in Example 1 and Comparative Example 1 is shown in FIG. 1, and it can be seen that the Sb-based chalcogenide thin-film solar cell in Example 1 can achieve an energy conversion efficiency of 8.77%, and the open circuit voltage, short circuit current density and fill factor are 31.78 mA / cm2, 438 mV and 63.08%, respectively, which has the highest efficiency value of the currently reported cadmium-free Sb-based chalcogenide thin-film solar cell. The energy conversion efficiency of the Sb-based chalcogenide thin-film solar cell in Comparative Example 1 is only 5.85%, and the open circuit voltage, short circuit current density and fill factor are 25.68 mA / cm2, 430 mV and 62.48%, respectively. Figure 4 2 , 438 mV and 63.08%, respectively, which has the highest efficiency value of the currently reported cadmium-free Sb-based chalcogenide thin-film solar cell. The energy conversion efficiency of the Sb-based chalcogenide thin-film solar cell in Comparative Example 1 is only 5.85%, and the open circuit voltage, short circuit current density and fill factor are 25.68 mA / cm​2 , 428 mV and 53.23%.

[0098] In summary, the present application provides a cadmium-free electron transport layer, antimony-based chalcogenide thin film solar cell and preparation method. The heterojunction band arrangement formed by the cadmium-free electron transport layer and the antimony-based chalcogenide semiconductor is in an ideal "spike-shaped" configuration, and the corresponding conduction band offset value is between 0 and 0.4 eV. The cadmium-free electron transport layer can effectively inhibit the accumulation and recombination of photo-generated carriers at the interface, and can also ensure efficient carrier separation and transport. The cadmium-free antimony-based chalcogenide thin film solar cell can achieve an energy conversion efficiency of 8.77%, and the open circuit voltage, short circuit current density and fill factor are 31.78 mA / cm 2 , 438 mV and 63.08%.

[0099] It should be understood that the application of the present application is not limited to the above examples, and can be improved or changed according to the above description for those skilled in the art, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.

Claims

1. A Sb-based chalcogenide thin-film solar cell, characterized by, The application relates to a solar cell, which comprises a substrate, a Sb-based chalcogenide semiconductor light absorption layer, an electron transport layer and a window layer which are sequentially arranged on the substrate, and a first electrode and a second electrode which are respectively arranged on the window layer and the substrate; the electron transport layer is a cadmium-free electron transport layer, and a preparation method of the cadmium-free electron transport layer comprises the following steps: S1, performing m times of cyclic deposition of ZnO monolayer by an atomic layer deposition method to obtain a first film layer; S2, performing n times of cyclic deposition of SnO2 monolayer on the first film layer by the atomic layer deposition method to obtain a second film layer; S3, repeating steps S1 to S2 for several times to obtain the cadmium-free electron transport layer; Wherein, m:n=(1~6):

1.

2. The antimony-based chalcogenide thin-film solar cell according to claim 1, characterized in that, In step S1, the steps of each time of ZnO monolayer deposition in the m times of cyclic deposition of ZnO monolayer specifically comprise the following steps: The temperature of the reaction chamber is set to 100~150 DEG C, then 40~80 ms of zinc precursor source pulse, 80~120 ms of first oxygen precursor source pulse and 5~10 s of inert gas blowing are sequentially performed in the reaction chamber.

3. The antimony-based chalcogenide thin-film solar cell according to claim 2, characterized in that, In step S2, the steps of each time of SnO2 monolayer deposition in the n times of cyclic deposition of SnO2 monolayer specifically comprise the following steps: The temperature of the reaction chamber is set to 100~150 DEG C, then 40~80 ms of tin precursor source pulse, 80~120 ms of second oxygen precursor source pulse and 5~10 s of inert gas blowing are sequentially performed in the reaction chamber.

4. The antimony-based chalcogenide thin-film solar cell according to claim 3, characterized in that, The zinc precursor source comprises at least one of diethyl zinc and zinc chloride, and the first oxygen precursor source comprises at least one of deionized water and ozone; The tin precursor source comprises at least one of tetra (dimethylamino) tin and tetraethyltin, and the second oxygen precursor source comprises at least one of deionized water and ozone.

5. The antimony-based chalcogenide thin-film solar cell according to claim 1, wherein In step S3, the several times are 30~50 times.

6. The antimony-based chalcogenide thin-film solar cell according to claim 1, wherein The antimony-based chalcogenide semiconductor light-absorbing layer includes Sb2(Se x S 1-x )3, 0≤x≤1; the antimony-based chalcogenide thin-film solar cell further includes a Sb2O3 passivation layer between the antimony-based chalcogenide semiconductor light-absorbing layer and the electron transport layer. The window layer comprises one of an indium tin oxide window layer, a fluorine-doped tin oxide window layer and an aluminum-doped zinc oxide window layer; The materials of the first electrode and the second electrode are at least one of silver, aluminum, copper and nickel.

7. A method of producing the antimony-based chalcogenide thin-film solar cell according to claim 1, characterized by, The application further relates to a preparation method of the solar cell, which comprises the following steps: providing a substrate; forming a Sb-based chalcogenide semiconductor light absorption layer on the substrate; forming a cadmium-free electron transport layer on the Sb-based chalcogenide semiconductor light absorption layer; forming a window layer on the cadmium-free electron transport layer; forming a first electrode and a second electrode on the window layer and the substrate respectively.

8. The production method according to claim 7, characterized by, The step of forming a Sb-based chalcogenide semiconductor light absorption layer on the substrate specifically comprises the following steps: forming a Sb precursor film on the substrate by a magnetron sputtering method; Then the Sb precursor film is subjected to a selenization treatment and / or a sulfurization treatment to generate Sb2(Se x S 1-x )3, 0≤x≤1, and further to obtain the antimony-based sulfur semiconductor light absorption layer.

Images