Perovskite solar cells with oxygen-vacant anatase TiO2 mesoporous hollow spherical electron transport layers

Abstract

This invention discloses a perovskite solar cell with an oxygen-vacancy-containing anatase TiO2 mesoporous hollow spherical electron transport layer. The perovskite solar cell sequentially comprises the following structure: a conductive glass layer, a dense layer, an electron transport layer, a perovskite layer, a hole transport layer, and an electrode layer; wherein the electron transport layer is an oxygen-vacancy-containing anatase TiO2 mesoporous hollow spherical layer. The perovskite solar cell of this invention exhibits improved photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention relates to a perovskite solar cell, and more particularly to a perovskite solar cell with an anatase TiO2 mesoporous hollow spherical electron transport layer containing oxygen vacancies. Background Technology

[0002] Solar energy is a highly efficient, safe, clean, and environmentally friendly new energy source. It is widely available and abundant, possessing enormous development potential. Perovskite solar cells exhibit excellent photoelectric performance and are simple to fabricate, low in cost, and green and efficient, demonstrating significant development potential. Perovskite solar cells have a "sandwich" structure, primarily composed of an electrode / charge transport layer / perovskite layer / charge transport layer / electrode. In the formal structure (nip), sunlight shines onto the device, passes through the transparent electrode, and first enters the electron transport layer.

[0003] The electron transport layer (ETL) plays a crucial role in perovskite solar cells, primarily functioning to extract and transport electrons, block holes, and act as a supporting framework. Therefore, ETL materials are typically n-type semiconductors with high electron affinity and ionic potential, facilitating electron extraction and transport. First, the ETL must match the energy levels of the perovskite material to facilitate the extraction and transport of photogenerated electrons. Second, the ETL must have an appropriate bandgap to suppress hole transport and reduce photogenerated carrier recombination. Furthermore, the thickness of the ETL also affects the balance of carrier transport across different layers, controlling charge accumulation and thus improving the solar cell's lifetime.

[0004] Titanium dioxide (TiO2) is a wide-bandgap n-type semiconductor with advantages such as good photoelectric properties, low cost, good chemical stability, and safety and non-toxicity. Furthermore, its conduction band minimum (CBM, -4.4 eV) and valence band maximum (VBM, -7.63 eV) are well-suited to the perovskite band structure, ensuring electron transport and blocking holes. Therefore, titanium dioxide (TiO2) is widely used as the electron transport layer in perovskite solar cells. However, titanium dioxide (TiO2) also has poor conductivity and low electron mobility (0.1-1 cm⁻¹). 2 V -1 S -1 Low conductivity (<10) -10 The limitations of TiO2, such as its energy level (s / cm), restrict its application. The mismatch in conduction band shift between TiO2 and perovskite materials also hinders electron extraction and transport between the perovskite film and the TiO2 electron transport layer. While doping or spraying can improve the energy level matching between the TiO2 electron transport layer and the light-absorbing layer, these methods are costly and complex, making them difficult to apply in practical production.

[0005] TiO2, as an electron transport layer, mainly exists in two structures: mesoporous TiO2 and compact TiO2 (c-TiO2). Defects and grain boundaries in TiO2 can become electron-hole recombination centers during the operation of perovskite solar cells, thus affecting the photovoltaic performance of the device. Furthermore, the mesoporous TiO2 layer, located between the compact titanium dioxide and the perovskite layer, increases the filling capacity of the perovskite material and improves light utilization. Currently, the preparation of mesoporous hollow TiO2 spheres mainly involves hydrothermal methods, solvothermal methods, template methods, sol-gel methods, and microemulsion methods, among others, resulting in relatively complex and cumbersome processes.

[0006] When TiO2 is used as an electron transport layer, defects and grain boundaries in the thin film become electron-hole recombination centers, forming an interface barrier that causes direct contact between the perovskite and the electrode, reducing photovoltaic efficiency and greatly affecting the performance of perovskite solar cell devices. Summary of the Invention

[0007] The purpose of this invention is to provide a perovskite solar cell with an anatase-type TiO2 mesoporous hollow spherical electron transport layer containing oxygen vacancies.

[0008] The perovskite solar cell provided by the present invention has the following structure in sequence: a conductive glass layer, a dense layer, an electron transport layer, a perovskite layer, a hole transport layer, and an electrode layer; wherein, the electron transport layer is an anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies.

[0009] The oxygen vacancy concentration of the anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies is 27.9-45.1%.

[0010] The oxygen vacancy concentration of the anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies is 34.2%. The conductive glass is ITO; the dense layer is a TiO2 layer; the hole transport layer is spiro-OMeTAD; and the electrode layer is an Ag layer.

[0011] Another object of the present invention is to provide a method for preparing perovskite solar cells, the method comprising:

[0012] A dense layer is prepared on a conductive glass layer;

[0013] An oxygen-vacancy-containing anatase TiO2 mesoporous hollow sphere layer is prepared on the dense layer as an electron transport layer;

[0014] A perovskite layer is prepared on the electron transport layer;

[0015] A hole transport layer is prepared on the perovskite layer; and

[0016] An electrode layer is fabricated on the hole transport layer.

[0017] In this process, oxygen-vacant anatase TiO2 mesoporous hollow spheres are dispersed in anhydrous ethanol, then spin-coated onto the dense layer, and annealed at 100°C to prepare the electron transport layer.

[0018] The oxygen vacancy concentration of the anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies is 27.9-45.1%.

[0019] The oxygen vacancy concentration of the anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies is 34.2%.

[0020] Wherein, the conductive glass is ITO; the dense layer is a TiO2 layer; the hole transport layer is spiro-OMeTAD; and the electrode layer is an Ag layer.

[0021] The perovskite solar cell of the present invention has improved photoelectric conversion efficiency. Attached Figure Description

[0022] Figure 1 A schematic diagram of the structure of the perovskite solar cell with an anatase TiO2 mesoporous hollow sphere electron transport layer containing oxygen vacancies is shown.

[0023] Figure 2 A schematic diagram of the preparation process of anatase TiO2 mesoporous hollow spheres containing oxygen vacancies is shown.

[0024] Figure 3 A TEM image of anatase TiO2 mesoporous hollow spheres containing oxygen vacancies is shown. Detailed Implementation

[0025] This invention provides a perovskite solar cell with an oxygen-vacant anatase TiO2 mesoporous hollow sphere electron transport layer. The cell has the following structure: a conductive glass layer, a dense layer, an electron transport layer, a perovskite layer, a hole transport layer, and an electrode layer; wherein the electron transport layer is an oxygen-vacant anatase TiO2 mesoporous hollow sphere layer.

[0026] Specifically, the battery, such as Figure 1 As shown, it has the following structure: ITO (conductive glass) / compact-TiO2 (dense TiO2 layer) / H-meso-TiO2 (anatase-type TiO2 mesoporous hollow spheres with oxygen vacancies) / perovskite (perovskite layer) / spiro-OMeTAD (hole transport layer) / Ag (electrode).

[0027] The conductive glass layer has a thickness of 160-180 nm; the dense layer has a thickness of 20-30 nm; the electron transport layer has a thickness of 80-100 nm; the perovskite layer has a thickness of 450-800 nm; the hole transport layer has a thickness of 100-150 nm; and the electrode layer has a thickness of 80-120 nm.

[0028] The oxygen-vacancy-containing anatase TiO2 mesoporous hollow spheres used in this invention are prepared by using tetrabutyl titanate as the titanium source and a self-made SiO2 precursor as a template, followed by heat treatment to introduce oxygen vacancies. The preparation process is as follows: Figure 2 As shown, firstly, a SiO2 template with controllable particle size was prepared; based on the SiO2, SiO2@TiO2 nanospheres were prepared: under magnetic stirring, tetrabutyl titanate was added dropwise to the dispersed SiO2 template to ensure uniform TiO2 deposition. After uniform mixing, the resulting white suspension was centrifuged at high speed to obtain SiO2@TiO2 nanospheres; the sample was placed in a muffle furnace and calcined at 500℃ for 2 hours under a mixed atmosphere (95% Ar + 5% H2) to introduce oxygen vacancies into the sample; the SiO2 in the sample was etched to obtain mesoporous TiO2 hollow nanospheres, which were then washed and dried.

[0029] Conventional electron transport layer materials TiO2 and SnO2 have weak capabilities in collecting, trapping, and transferring free electrons generated by light absorption in the perovskite layer. Furthermore, charge recombination easily occurs at the interface between the perovskite layer and the electron transport layer, resulting in unsatisfactory electron mobility in the electron transport layer of perovskite solar cells, and consequently, low power conversion efficiency (PCE). Compared to conventional dense TiO2 electron transport layers, oxygen-vacant anatase TiO2 mesoporous hollow spheres have a high specific surface area and a large contact area with the perovskite layer. The surface oxygen vacancies provide more transport channels for photogenerated carriers. These oxygen-vacant anatase TiO2 mesoporous hollow spheres provide skeletal support for perovskite crystal growth, facilitating uniform crystal growth, improving interface recombination, shortening carrier transport paths, and increasing the conversion efficiency of incident photons to current. Moreover, the interconnectedness of anatase TiO2 particles through the mesoporous structure further enhances electron transport performance. The introduction of oxygen vacancies can improve the conductivity of the electron transport layer, capture and collect more charge carriers generated after light absorption in the perovskite layer, improve the electron transport rate, optimize the photovoltaic performance of perovskite solar cells, and improve the photoelectric conversion efficiency.

[0030] Oxygen-vacant anatase TiO2 mesoporous hollow spheres are used as electron transport materials in the electron transport layer of solar cells. The nanoparticles can carry the original free electrons and effectively transfer them to the semiconductor particles. This allows the nanoparticles to provide more electron vacancies to capture and collect the charge carriers generated after light absorption in the perovskite layer. This is beneficial to improving the separation efficiency of photogenerated charge carriers in the perovskite layer of the solar cell (i.e., delaying electron-hole recombination, so that the free electrons and holes generated by light are effectively separated in space), which is beneficial to improving the electron mobility of the electron transport layer, and thus beneficial to improving the power conversion efficiency of the solar cell.

[0031] Example 1: Fabrication of a perovskite solar cell with anatase-type TiO2 mesoporous hollow spherical electron transport layer containing low concentrations of oxygen vacancies.

[0032] Preparation of oxygen-vacancy-containing anatase TiO2 mesoporous hollow spheres

[0033] 1. Precursor preparation:

[0034] 280 mL of anhydrous ethanol and 56 mL of deionized water were measured into 500 mL beakers. Then, 8.4 mL of ammonia water was added dropwise to the beakers while stirring for 15 min to ensure homogeneous mixing. Next, tetraethyl orthosilicate (TEOS) was added to the mixture under magnetic stirring, and the mixture was stirred continuously at room temperature (20℃±5℃) for 24 h. The resulting white suspension was then removed and centrifuged at 8000 r / min for 10 min to obtain SiO2 nanospheres. The SiO2 nanospheres were washed three times each with deionized water and anhydrous ethanol, and then dried in a 65℃ oven for 8 h. The dried SiO2 nanospheres were then ground in an agate mortar and then stored in sample tubes.

[0035] 2. Preparation of mesoporous TiO2 hollow nanospheres

[0036] First, 50 mg of the prepared SiO2 nanospheres were weighed using an electronic balance and dispersed in 120 mL of anhydrous ethanol by ultrasonication for 15 min. Next, 0.5 mL of NH3·H2O was added to the dispersed suspension under magnetic stirring, and stirring was continued for 15 min to ensure homogeneity. Then, 1 mL of TBOT (butyl titanate) was slowly added dropwise to the suspension at room temperature (20℃±5℃), followed by continuous magnetic stirring for 4 h to obtain a white suspension. The white suspension obtained under magnetic stirring was then removed and centrifuged at 8000 r / min for 15 min to obtain SiO2@TiO2 nanospheres. Figure 3 A TEM image of SiO2@TiO2 nanospheres is shown.

[0037] 3. Heat treatment

[0038] The SiO2 / TiO2 nanospheres prepared above were placed in a ceramic boat and calcined in a muffle furnace at 500°C for 2 hours in air and mixed atmosphere (5% H2 + 95% Ar) (heating rate of 2° / min). After the muffle furnace cooled to room temperature, the materials were removed to obtain SiO2 / A-TiO2 materials with different concentrations of oxygen vacancies.

[0039] The SiO2 / A-TiO2 materials with different oxygen vacancies were dissolved in NaOH aqueous solution (2 mol / L) and magnetically stirred for 3 h at room temperature to ensure that all SiO2 was etched. Finally, the obtained mesoporous TiO2 hollow nanospheres were washed with deionized water and anhydrous ethanol until neutral, and then dried in a 65℃ oven for 8 h. The dried mesoporous TiO2 hollow nanospheres were then ground in an agate mortar and stored in sample tubes.

[0040] Fabrication of perovskite solar cells with anatase-type TiO2 mesoporous hollow spherical electron transport layers containing oxygen vacancies

[0041] After ultrasonic cleaning and drying, the ITO glass was purged with nitrogen and treated with UV for 15 minutes. In a glove box, 1 mg of dense TiO2 was dispersed in 1 ml of anhydrous ethanol, thoroughly mixed, and then spin-coated onto the treated ITO (4000 rpm, 30 s). After spin-coating, it was annealed at 100°C for 10 minutes on a hot plate. Similarly, 1 mg of oxygen-vacant anatase TiO2 mesoporous hollow spheres was dispersed in 1 ml of anhydrous ethanol and spin-coated onto the sample from the previous step (4000 rpm, 30 s), followed by annealing at 100°C for 10 minutes.

[0042] In a glove box, a perovskite precursor (MACl (6.1 mg), MABr (6.7 mg), CsI (23.4 mg), FABr (37.5 mg), FAI (165.1 mg), PbI2 (691.5 mg)) was prepared and dissolved in 1 mL of DMF / DMSO (volume ratio 4:1). 100 μL of the precursor was taken and spin-coated at 5000 rpm for 30 s. At the last five seconds, 200 μL of chlorobenzene antisolvent was added dropwise, followed by annealing at 125 °C for 30 min.

[0043] Spiro-OMeTAD was used as the hole transport layer. First, 101.2 mg of Spiro-OMeTAD powder was weighed in a glove box and dissolved in 1 mL of chlorobenzene (CB). Then, 520 mg of Li-TFSI was weighed and dissolved in 1 mL of acetonitrile to obtain a lithium salt solution, and 320 mg of FK-209 was weighed and dissolved in 1 mL of acetonitrile to obtain a cobalt salt solution. Additives (17.5 μL of lithium salt solution, 29 μL of cobalt salt solution, and 28 μL of tetra-tert-butylpyridine (tBP)) were added to 1 mL of the Spiro-OMeTAD precursor solution and stirred at room temperature for 15 min. 80 μL of the Spiro-OMeTAD solution was then spin-coated for 30 s at an acceleration of 5000 rad / s and a rotation speed of 5000 rpm, followed by standing in a glove box for 12 h.

[0044] Finally, a silver electrode with a thickness of 100 nm was deposited on the substrate using a metal evaporation device.

[0045] Example 2: Fabrication of a perovskite solar cell with an anatase-type TiO2 mesoporous hollow spherical electron transport layer containing a moderate concentration of oxygen vacancies.

[0046] Preparation of oxygen-vacancy-containing anatase Ti O2 Mesoporous hollow sphere

[0047] 1. Precursor preparation:

[0048] 280 mL of anhydrous ethanol and 56 mL of deionized water were measured into 500 mL beakers. Then, 8.4 mL of ammonia water was added dropwise to the beakers while stirring for 15 min to ensure homogeneous mixing. Next, tetraethyl orthosilicate (TEOS) was added to the mixture under magnetic stirring, and the mixture was stirred continuously at room temperature (20℃±5℃) for 24 h. The resulting white suspension was then removed and centrifuged at 8000 r / min for 10 min to obtain SiO2 nanospheres. The SiO2 nanospheres were washed three times each with deionized water and anhydrous ethanol, and then dried in a 65℃ oven for 8 h. The dried SiO2 nanospheres were then ground in an agate mortar and then stored in sample tubes.

[0049] 2. Preparation of mesoporous TiO2 hollow nanospheres

[0050] First, 50 mg of the prepared SiO2 nanospheres were weighed using an electronic balance and dispersed in 120 mL of anhydrous ethanol by ultrasonication for 15 min. Next, 0.5 mL of NH3·H2O was added to the dispersed suspension under magnetic stirring, and stirring was continued for 15 min to ensure homogeneity. Then, 1 mL of TBOT (butyl titanate) was slowly added dropwise to the suspension at room temperature (20℃±5℃), followed by continuous magnetic stirring for 4 h to obtain a white suspension. The white suspension obtained under magnetic stirring was then removed and centrifuged at 8000 r / min for 15 min to obtain SiO2@TiO2 nanospheres.

[0051] 3. Heat treatment

[0052] The SiO2 / TiO2 nanospheres prepared above were placed in a ceramic boat and calcined in a muffle furnace at 500°C for 4 hours in air atmosphere and mixed atmosphere (5% H2 + 95% Ar) (heating rate of 2° / min). After the muffle furnace cooled to room temperature, the materials were removed to obtain SiO2 / A-TiO2 materials with different concentrations of oxygen vacancies.

[0053] The SiO2 / A-TiO2 materials with different oxygen vacancies were dissolved in NaOH aqueous solution (2 mol / L) and magnetically stirred for 3 h at room temperature to ensure that all SiO2 was etched. Finally, the obtained mesoporous TiO2 hollow nanospheres were washed with deionized water and anhydrous ethanol until neutral, and then dried in a 65℃ oven for 8 h. The dried mesoporous TiO2 hollow nanospheres were then ground in an agate mortar and stored in sample tubes.

[0054] Preparation of anatase Ti with oxygen vacancies O2 Perovskite solar cells with mesoporous hollow spherical electron transport layers

[0055] After ultrasonic cleaning and drying, the ITO glass was purged with nitrogen and treated with UV for 15 minutes. In a glove box, 1 mg of dense TiO2 was dispersed in 1 ml of anhydrous ethanol, thoroughly mixed, and then spin-coated onto the treated ITO (4000 rpm, 30 s). After spin-coating, it was annealed at 100°C for 10 minutes on a hot plate. Similarly, 1 mg of oxygen-vacant anatase TiO2 mesoporous hollow spheres was dispersed in 1 ml of anhydrous ethanol and spin-coated onto the sample from the previous step (4000 rpm, 30 s), followed by annealing at 100°C for 10 minutes.

[0056] In a glove box, a perovskite precursor (MACl (6.1 mg), MABr (6.7 mg), CsI (23.4 mg), FABr (37.5 mg), FAI (165.1 mg), PbI2 (691.5 mg)) was prepared and dissolved in 1 mL of DMF / DMSO (volume ratio 4:1). 100 μL of the precursor was taken and spin-coated at 5000 rpm for 30 s. At the last five seconds, 200 μL of chlorobenzene antisolvent was added dropwise, followed by annealing at 125 °C for 30 min.

[0057] Spiro-OMeTAD was used as the hole transport layer. First, 101.2 mg of Spiro-OMeTAD powder was weighed in a glove box and dissolved in 1 mL of chlorobenzene (CB). Then, 520 mg of Li-TFSI was weighed and dissolved in 1 mL of acetonitrile to obtain a lithium salt solution, and 320 mg of FK-209 was weighed and dissolved in 1 mL of acetonitrile to obtain a cobalt salt solution. Additives (17.5 μL of lithium salt solution, 29 μL of cobalt salt solution, and 28 μL of tetra-tert-butylpyridine (tBP)) were added to 1 mL of the Spiro-OMeTAD precursor solution and stirred at room temperature for 15 min. 80 μL of the Spiro-OMeTAD solution was then spin-coated for 30 s at an acceleration of 5000 rad / s and a rotation speed of 5000 rpm, followed by standing in a glove box for 12 h.

[0058] Finally, a silver electrode with a thickness of 100 nm was deposited on the substrate using a metal evaporation device.

[0059] Example 3: Fabrication of a perovskite solar cell with an anatase-type TiO2 mesoporous hollow spherical electron transport layer containing a high concentration of oxygen vacancies.

[0060] Preparation of oxygen-vacancy-containing anatase Ti O2 Mesoporous hollow sphere

[0061] 1. Precursor preparation:

[0062] 280 mL of anhydrous ethanol and 56 mL of deionized water were measured into 500 mL beakers. Then, 8.4 mL of ammonia water was added dropwise to the beakers while stirring for 15 min to ensure homogeneous mixing. Next, tetraethyl orthosilicate (TEOS) was added to the mixture under magnetic stirring, and the mixture was stirred continuously at room temperature (20℃±5℃) for 24 h. The resulting white suspension was then removed and centrifuged at 8000 r / min for 10 min to obtain SiO2 nanospheres. The SiO2 nanospheres were washed three times each with deionized water and anhydrous ethanol, and then dried in a 65℃ oven for 8 h. The dried SiO2 nanospheres were then ground in an agate mortar and then stored in sample tubes.

[0063] 2. Preparation of mesoporous TiO2 hollow nanospheres

[0064] First, 50 mg of the prepared SiO2 nanospheres were weighed using an electronic balance and dispersed in 120 mL of anhydrous ethanol by ultrasonication for 15 min. Next, 0.5 mL of NH3·H2O was added to the dispersed suspension under magnetic stirring, and stirring was continued for 15 min to ensure homogeneity. Then, 1 mL of TBOT (butyl titanate) was slowly added dropwise to the suspension at room temperature (20℃±5℃), followed by continuous magnetic stirring for 4 h to obtain a white suspension. The white suspension obtained under magnetic stirring was then removed and centrifuged at 8000 r / min for 15 min to obtain SiO2@TiO2 nanospheres.

[0065] 3. Heat treatment

[0066] The SiO2 / TiO2 nanospheres prepared above were placed in a ceramic boat and calcined in a muffle furnace at 500°C for 6 hours in air and mixed atmosphere (5% H2 + 95% Ar) (heating rate of 2° / min). After the muffle furnace cooled to room temperature, the material was removed to obtain SiO2 / A-TiO2 material with high oxygen vacancy concentration.

[0067] The SiO2 / A-TiO2 materials with different oxygen vacancies were dissolved in NaOH aqueous solution (2 mol / L) and magnetically stirred for 3 h at room temperature to ensure that all SiO2 was etched. Finally, the obtained mesoporous TiO2 hollow nanospheres were washed with deionized water and anhydrous ethanol until neutral, and then dried in a 65℃ oven for 8 h. The dried mesoporous TiO2 hollow nanospheres were then ground in an agate mortar and stored in sample tubes.

[0068] Fabrication of perovskite solar cells with anatase-type TiO2 mesoporous hollow spherical electron transport layers containing oxygen vacancies

[0069] After ultrasonic cleaning and drying, the ITO glass was purged with nitrogen and treated with UV for 15 minutes. In a glove box, 1 mg of dense TiO2 was dispersed in 1 ml of anhydrous ethanol, thoroughly mixed, and then spin-coated onto the treated ITO (4000 rpm, 30 s). After spin-coating, it was annealed at 100°C for 10 minutes on a hot plate. Similarly, 1 mg of oxygen-vacant anatase TiO2 mesoporous hollow spheres was dispersed in 1 ml of anhydrous ethanol and spin-coated onto the sample from the previous step (4000 rpm, 30 s), followed by annealing at 100°C for 10 minutes.

[0070] In a glove box, a perovskite precursor (MACl (6.1 mg), MABr (6.7 mg), CsI (23.4 mg), FABr (37.5 mg), FAI (165.1 mg), PbI2 (691.5 mg)) was prepared and dissolved in 1 mL of DMF / DMSO (volume ratio 4:1). 100 μL of the precursor was taken and spin-coated at 5000 rpm for 30 s. At the last five seconds, 200 μL of chlorobenzene antisolvent was added dropwise, followed by annealing at 125 °C for 30 min.

[0071] Spiro-OMeTAD was used as the hole transport layer. First, 101.2 mg of Spiro-OMeTAD powder was weighed in a glove box and dissolved in 1 mL of chlorobenzene (CB). Then, 520 mg of Li-TFSI was weighed and dissolved in 1 mL of acetonitrile to obtain a lithium salt solution, and 320 mg of FK-209 was weighed and dissolved in 1 mL of acetonitrile to obtain a cobalt salt solution. Additives (17.5 μL of lithium salt solution, 29 μL of cobalt salt solution, and 28 μL of tetra-tert-butylpyridine (tBP)) were added to 1 mL of the Spiro-OMeTAD precursor solution and stirred at room temperature for 15 min. 80 μL of the Spiro-OMeTAD solution was then spin-coated for 30 s at an acceleration of 5000 rad / s and a rotation speed of 5000 rpm, followed by standing in a glove box for 12 h.

[0072] Finally, a silver electrode with a thickness of 100 nm was deposited on the substrate using a metal evaporation device.

[0073] Quantitative analysis of oxygen vacancy concentration: (Gaussian fitting: Oc: lattice oxygen, Ti-O bond; Oa: adsorbed oxygen)

[0074] Oc(BE / eV) Oa(BE / eV) Content Oa / % <![CDATA[TiO2]]> 530.59±0.04 531.89±0.02 23.1 low concentration oxygen vacancy 530.14±0.05 531.72±0.03 27.9 Moderate concentration of oxygen vacancies 530.18±0.02 532.21±0.06 34.2 High concentration of oxygen vacancies 530.22±0.05 532.47±0.03 45.1

[0075] Electron mobility of perovskite solar cells with anatase-type TiO2 mesoporous hollow spherical electron transport layers containing different concentrations of oxygen vacancies

[0076]

Claims

1. A perovskite solar cell, characterized by, It has the following layers in sequence: a conductive glass layer, a dense layer, an electron transport layer, a perovskite layer, a hole transport layer, and an electrode layer; wherein, the electron transport layer is an anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies. The oxygen vacancy concentration of the anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies is 27.9-45.1%.

2. The perovskite solar cell according to claim 1, characterized in that, The oxygen vacancy concentration of the anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies is 34.2%. 3.The perovskite solar cell of claim 1, wherein, The conductive glass is ITO; the dense layer is a TiO2 layer; the hole transport layer is spiro0MeTAD; and the electrode layer is an Ag layer. 4.The perovskite solar cell of claim 1, wherein The thickness of the conductive glass layer is 160-180 nm; the thickness of the dense layer is 20-30 nm; the thickness of the electron transport layer is 80-100 nm; the thickness of the perovskite layer is 450-800 nm; the thickness of the hole transport layer is 100-150 nm; and the thickness of the electrode layer is 80-120 nm.

5. A method for preparing a perovskite solar cell, characterized by, The method includes: A dense layer is prepared on a conductive glass layer; An oxygen-vacancy-containing anatase TiO2 mesoporous hollow sphere layer is prepared on the dense layer as an electron transport layer; A perovskite layer is prepared on the electron transport layer; A hole transport layer is prepared on the perovskite layer; and An electrode layer is fabricated on the hole transport layer; The oxygen vacancy concentration of the anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies is 27.9-45.1%.

6. The method of claim 5, wherein, Anatase TiO2 mesoporous hollow spheres containing oxygen vacancies were dispersed in anhydrous ethanol, then spin-coated onto the dense layer, and annealed at 100°C to prepare the electron transport layer.

7. The method of claim 5, wherein, The oxygen vacancy concentration of the anatase TiO2 mesoporous hollow sphere layer containing oxygen vacancies is 34.2%.

8. The method of claim 5, wherein, The conductive glass is ITO; the dense layer is a TiO2 layer; the hole transport layer is spiro0MeTAD; and the electrode layer is an Ag layer.

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