Inorganic perovskite CsPbBr 3 Quantum dot-modified SiO 2 @SiO 2 @TiO 2 Preparation method and application of microspheres

Abstract

The present invention discloses a preparation method and application of inorganic perovskite CsPbBr3 quantum dots modified SiO2@SiO2@TiO2 microspheres. Among them, SiO2@SiO2@TiO2-CsPbBr3 is a core-shell structure composed of SiO2@SiO2 as the core layer and TiO2 as the shell layer, and CsPbBr3 particles are modified between the TiO2 shell layer and the core layer and the shell layer. The SiO2@SiO2@TiO2-CsPbBr3 hierarchical microspheres of the present invention improve the absorption and charge separation of the photoanode through the scattering effect of the microspheres, high specific surface area, and high light absorption of CsPbBr3. Doping 10% of the SiO2@SiO2@TiO2-CsPbBr3 composite material in the photoanode of P25 can improve the current density and photoelectric conversion efficiency of the battery, and the short-circuit current density increases from 8.91 mA / cm 2 to 14.34 mA / cm 2 , and the photogenerated conversion efficiency increases from 4.51% to 7.11%.

Description

Technical Field

[0001] The present invention belongs to the field of solar cells (dye-sensitized solar cell electrode materials), and particularly relates to a preparation method and application of inorganic perovskite CsPbBr 3 quantum dot-modified SiO 2 @SiO 2 @TiO 2 microspheres. Background Art

[0002] Environment and energy have become two important issues affecting the sustainable development of human society. Therefore, as the most important environmentally friendly renewable energy, solar energy has attracted increasing attention from society. Reasonable and efficient utilization of solar energy is the key to solving the above problems. Among them, dye-sensitized solar cells (DSSCs) have gradually become strong competitors for the third-generation high-efficiency solar cells due to their low cost, low power consumption, simple process, high theoretical efficiency, etc. Constructing a new type of photoanode composite structure is of great significance for developing more efficient solar cells.

[0003] SiO 2 @SiO 2 @TiO 2 microspheres with their special morphology have a large specific surface area, effectively increasing the adsorption capacity for dyes, and the high scattering effect of the microspheres. The all-inorganic perovskite CsPbBr 3 quantum dots have excellent visible light capture ability and tunable band structure, effectively improving the light absorption ability and charge separation ability of the photoanode. Through the synergistic effect of inorganic perovskite CsPbBr 3 quantum dots and SiO 2 @SiO 2 @TiO 2 microspheres, it helps to improve the optoelectronic performance of DSSCs. Summary of the Invention

[0004] The present invention aims to provide a preparation method and application of inorganic perovskite CsPbBr 3 quantum dot-modified SiO 2 @SiO 2 @TiO 2 microspheres, and the technical problem to be solved is to increase the light absorption of the photoanode through the design and synthesis of microspheres.

[0005] The CsPbBr 3 perovskite quantum dot-modified SiO 2 @SiO 2 @TiO 2 hierarchical microspheres, briefly denoted as SiO 2 @SiO 2 @TiO 2-CsPbBr 3 uses SiO 2 @SiO 2 as the core layer, TiO 2 as the shell layer, and inorganic perovskite CsPbBr 3 quantum dot particles are modified on the shell layer and inside. CsPbBr 3 is mainly distributed on the surface of the TiO 2 shell layer, and part enters the inside of the shell layer.

[0006] The CsPbBr 3 quantum dot-modified SiO 2 @SiO 2 @TiO 2 microsphere preparation method includes the following steps:

[0007] Step 1: Take 3.3 mL of ammonia water, 9.9 mL of deionized water and 33.4 mL of ethanol and mix them in a beaker, then quickly add 3.4 mL of tetraethyl orthosilicate and stir vigorously for 1 h; take 1 / 8 volume of the mixed solution as the mother liquor, add 3.3 mL of ammonia water, 9.9 mL of deionized water and 33.4 mL of ethanol to the mother liquor, quickly add 3.4 mL of tetraethyl orthosilicate, stir vigorously for 1 h, after the reaction is completed, centrifuge, wash and dry to obtain SiO 2 microspheres;

[0008] Step 2: Weigh 0.2 g of the SiO 2 microspheres prepared in Step 1, 0.2 g of cetyltrimethylammonium bromide, 0.184 mL of isopropanol, 0.12 g of urea and disperse them in 6 mL of deionized water, add 0.056 mol of organic solvent and 0.2 mL of tetraethyl orthosilicate to it, stir at room temperature for 5 min (200 r / min), then heat to 70 °C and react for 16 h, after the reaction is completed, centrifuge, wash and dry, and then anneal at 550 °C in a muffle furnace for 2 h to obtain SiO 2 @SiO 2 microspheres. SiO 2 @SiO 2 microspheres have a dendritic structure on the shell layer. Changing the reaction conditions will affect the microstructure, and the time, organic solvent and the content of tetraethyl orthosilicate all have an impact. In the present invention, the influence of different organic solvents is explored, and toluene is the preferred condition.

[0009] Step 3: Weigh 0.1 g of the SiO 2 @SiO 2The microspheres were dispersed in 17.5 mL of ethanol, 5.84 mL of acetonitrile and 0.17 mL of ammonia water. Under vigorous stirring, a mixed solution composed of 2.5 mL of ethanol, 0.83 mL of acetonitrile and 0.42 - 0.58 mL of tetrabutyl titanate was added thereto. After reacting for 1 h, it was centrifuged, washed and dried, and then annealed at 550 °C in a muffle furnace for 4 h to obtain SiO 2 @SiO 2 @TiO 2 microspheres.

[0010] Step 4: Take 0.5 g of Cs 2 CO 3 and 1.56 mL of oleic acid and 18.75 mL of octadecene were added to a three-necked flask and heated to 130 °C under N 2 atmosphere and kept warm for 1 h, then the temperature was raised to 150 °C and maintained for 30 min to obtain a Cs precursor; 0.14 g of PbBr 2 and 10 mL of octadecene, 1 mL of oleic acid, 1 mL of oleylamine were added to the three-necked flask and heated to 130 °C under N 2 atmosphere and kept warm for 1 h until PbBr 2 was completely dissolved, then the temperature was raised to 165 °C and kept warm for 5 min, and then 1 mL of the cesium precursor was quickly injected into the mixture and reacted for 5 s. The reaction was stopped in an ice-water bath, and ethyl acetate was added to precipitate CsPbBr 3 . The product was obtained by centrifugation, washed with toluene, and dried in vacuo to obtain CsPbBr 3 perovskite quantum dots.

[0011] Step 5: Weigh 1 - 5 mg of CsPbBr 3 and disperse it in 10 mL of toluene, then add 0.05 g of SiO 2 @SiO 2 @TiO 2 microspheres, stir overnight, centrifuge and dry in vacuo at 70 °C for 10 h to obtain SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 composite material.

[0012] In Step 1, the molar ratio of the ammonia water, deionized water, ethanol and tetraethyl orthosilicate is 5.56:35.71:37.01:1.

[0013] In Step 2, the molar ratio of the cetyltrimethylammonium bromide, isopropanol, urea, deionized water, toluene and tetraethyl orthosilicate is 0.63:2.68:2.23:372:63:1.

[0014] In Step 2, the organic solvent is selected from cyclohexane, benzene, and toluene, with toluene being preferred.

[0015] In Step 3, the molar ratio of the ethanol, acetonitrile, and ammonia water mixed solution is 68.2:25:1, and the molar ratio of the ethanol, acetonitrile, and tetrabutyl titanate is 35.75:13.08:1.

[0016] In Step 4, during the preparation of the Cs precursor, the molar ratio of Cs 2 CO 3 , oleic acid, and octadecene is 1:3.21:38.37; during the preparation of the CsPbBr 3 perovskite quantum dots, the molar ratio of PbBr 2 , octadecene, oleic acid, and oleylamine is 1:81.58:8.29:7.89.

[0017] The application of the CsPbBr 3 quantum dot-modified SiO 2 @SiO 2 @TiO 2 hierarchical microspheres is to use the SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres as a light absorber in the photoanode material, and utilize the advantages of the wide visible light absorption and adjustable bandgap of CsPbBr 3 to further enhance the light absorption of the composite material.

[0018] Furthermore, when the SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres and titanium dioxide P25 are mixed at a mass ratio of 10:90 and applied to the photoanode material, it can increase the light absorption of the photoanode, improve the short-circuit current of the battery, and improve the photoelectric conversion efficiency of the solar cell. Among them, the short-circuit current density increases from 8.91 mA / cm 2 to 14.34 mA / cm 2 , and the photogenerated conversion efficiency increases from 4.51% to 7.11%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the synthesis route of the present invention.

[0020] Figure 2 It is for the CsPbBr 3 modified SiO 2 @SiO 2 @TiO 2X-ray diffraction pattern of the hierarchical microspheres.

[0021] Figure 3 For the CsPbBr of the present invention 3 modified SiO 2 @SiO 2 @TiO 2 SiO in the hierarchical microspheres 2 @SiO 2 @TiO 2 low-temperature N 2 adsorption / desorption curve.

[0022] Figure 4 For the CsPbBr of the present invention 3 modified SiO 2 @SiO 2 @TiO 2 TEM image of the hierarchical microspheres.

[0023] Figure 5 For the CsPbBr of the invention 3 modified SiO 2 @SiO 2 @TiO 2 Element mapping of the hierarchical microspheres in a scanning electron microscope environment.

[0024] Figure 6 For the CsPbBr of the present invention 3 modified SiO 2 @SiO 2 @TiO 2 Relationship between the light absorption intensity and wavelength of the hierarchical microspheres between 200 nm and 800 nm.

[0025] Figure 7 For the CsPbBr of the present invention 3 modified SiO 2 @SiO 2 @TiO 2 Photocurrent-photovoltage diagram of a solar cell with the hierarchical microspheres at different CsPbBr 3 contents. Detailed implementation mode

[0026] The technical solution of the present invention is further analyzed and described through the following examples, but is not limited to the examples.

[0027] Example 1: Preparation and characterization of SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 Hierarchical microspheres

[0028] Figure 1For the SiO of the present invention 2 @SiO 2 @TiO 2 -CsPbBr 3 Preparation method of hierarchical microspheres. The SiO microspheres were synthesized by an improved 2 method as follows: Take 3.3 mL of ammonia water, 9.9 mL of deionized water and 33.4 mL of ethanol and mix them in a beaker. Quickly add 3.4 mL of tetraethyl orthosilicate into it. After stirring vigorously for 1 h, take 1 / 8 volume of the mixed solution as the mother liquor. Add 3.3 mL of ammonia water, 9.9 mL of deionized water and 33.4 mL of ethanol to the mother liquor, quickly add 3.4 mL of tetraethyl orthosilicate, stir vigorously for 1 h. After the reaction is completed, centrifuge, wash and dry to obtain silicon dioxide particles.

[0029] The SiO 2 @SiO 2 microspheres were synthesized by a two-phase method. Weigh SiO 2 particles (0.2 g), 0.2 g of cetyltrimethylammonium bromide, 0.184 mL of isopropanol, 0.12 g of toluene and disperse them in 6 mL of deionized water. Add 6 mL of toluene and 0.2 mL of tetraethyl orthosilicate into it. After stirring at room temperature for 5 min, heat to 70 °C and react for 16 h. After the reaction is completed, centrifuge, wash and dry, and then anneal in a muffle furnace at 550 °C for 2 h to obtain SiO 2 @SiO 2 microspheres.

[0030] Modify the SiO 2 @SiO 2 @SiO 2 microspheres with TiO 2 @SiO 2 (0.1 g) microspheres are dispersed in 17.5 mL of ethanol, 5.84 mL of acetonitrile and 0.17 mL of ammonia water. Under vigorous stirring, add a mixed solution of 2.5 mL of ethanol, 0.83 mL of acetonitrile and 0.42 mL of tetrabutyl titanate into it. After reacting for 1 h, centrifuge, wash and dry, and then anneal in a muffle furnace at 550 °C for 4 h to obtain SiO 2 @SiO 2 @TiO 2 microspheres.

[0031] Synthesize CsPbBr 3 perovskite quantum dots by a hot injection method. Take Cs 2 CO 3 (0.5 g), 1.56 mL of oleic acid and 18.75 mL of octadecene and add them into a three-necked flask. Under N 2Heat to 130 °C in an atmosphere and hold for 1 h, then raise the temperature to 150 °C and maintain for 30 min to obtain the Cs precursor. Add PbBr 2 (0.14 g), 10 mL of octadecene, 1 mL of oleic acid, and 1 mL of oleylamine into a three-necked flask, and heat to 130 °C in an N 2 atmosphere and hold for 1 h until PbBr 2 is completely dissolved. Then raise the temperature to 165 °C and hold for 5 min, and then quickly inject 1 mL of the cesium precursor into the mixture, react for 5 s, stop the reaction in an ice-water bath, add ethyl acetate to precipitate CsPbBr 3 , centrifuge to obtain the product, wash the product with toluene, and dry it under vacuum.

[0032] Synthesize SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 composite material. Weigh 1 - 5 mg of CsPbBr 3 , disperse it in 10 mL of toluene, and then add SiO 2 @SiO 2 @TiO 2 (0.05 g), stir overnight, centrifuge to obtain the product, and dry it under vacuum at 70 °C for 10 h. Obtain SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 composite material.

[0033] Figure 2 This is the X-ray diffraction pattern of the SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres. The XRD pattern of SiO 2 @SiO 2 @TiO 2 shows broad peaks at 25.3°, 37.9°, 48.1°, 54.0°, 55.2°, 62.8°, 70.3° and 75.2°, corresponding to the (101), (004), (200), (105), (211), (204), (220) and (215) crystal planes of anatase TiO 2 (JCPDS No. 21 - 1272). SiO 2 @SiO 2 @TiO 2 -CsPbBr 3The diffraction pattern shows broad peaks at 15.2°, 21.5°, 30.7°, 34.5°, 43.7°, and 46.6°, corresponding to the (100), (110), (200), (210), (202), and (212) crystal planes of CsPbBr 3 (JCPDS No. 18 - 0364). SiO 2 @SiO 2 @TiO 2 The characteristic peaks of CsPbBr 3 are all reflected in the X - ray diffraction pattern of SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 In the X - ray diffraction pattern of SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 The more the amount of CsPbBr 3 in CsPbBr 3 the higher the characteristic peak of CsPbBr 2 @SiO 2 @TiO 2 -CsPbBr 3 The diffraction peaks in CsPbBr 2 @SiO 2 @TiO 2 -CsPbBr 3 are clear, high - intensity, and sharp, indicating that SiO

[0034] Figure 3 This is the low - temperature N 2 @SiO 2 @TiO 2 adsorption / desorption curve of the SiO 2 microspheres of the present invention. The inset is the BJH desorption pore size distribution curve of the SiO 2 @SiO 2 @TiO 2 microspheres. It can be seen from the figure that the SiO 2 @SiO 2 @TiO 2 microspheres have a mesoporous structure, with a specific surface area of 120 m 2 / g, which is more conducive to the adsorption of dyes at a high specific surface area.

[0035] Figure 4 This is the TEM image of the SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres of the present invention. In Figure a, SiO2 @SiO 2 The microspheres have a good dendritic structure and a high specific surface area, which is beneficial to the adsorption of dyes. In Figure b, SiO 2 @SiO 2 @TiO 2 has a special morphology. TiO 2 is mainly distributed in the shell layer. At the dendritic interface between the shell layer and SiO 2 and SiO 2 @SiO 2 there are also some TiO 2 particles. In Figure c, SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 has a morphology similar to that of SiO 2 @SiO 2 @TiO 2 microspheres. Among them, CsPbBr 3 in Figure d shows a cubic crystal phase, has good dispersibility, and the size is concentrated at about 9 nm. Figure 3 shows that the pore size distribution of SiO 2 @SiO 2 @TiO 2 microspheres is in the range of 2 - 15 nm, making SiO 2 @SiO 2 @TiO 2 microspheres an ideal matrix for accommodating CsPbBr 3 perovskite quantum dots.

[0036] Figure 5 This is the elemental mapping diagram of the SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres of the present invention. It can be seen from Figure 5 that the elements Ti, O, Si, Cs, Pb, and Br exist and are evenly distributed. The elemental mapping spectrum further shows that the Si element is mainly distributed in the core layer, the Ti element is mainly distributed in the shell layer, and the Cs, Pb, and Br elements are evenly distributed in the SiO 2 @SiO 2 @TiO 2 microspheres.

[0037] Example 2: Preparation of SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres in a photoanode

[0038] Clean the FTO glass (2.2 mm, 14 Ω / sq) with acetone, ethanol, and deionized water under ultrasonic waves, and dry it for later use. First, disperse and stir a typical slurry containing 0.5 mL of terpineol, SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 (0.01 g) of hierarchical microsphere powder and P25 (0.09 g) for 30 minutes, and coat the resulting slurry on a clean FTO plate with an area of 0.25 cm 2 to form a uniform thin film. After drying and annealing at 450 °C for about 30 minutes, a photoanode thin film is obtained.

[0039] Figure 6 Shows the ultraviolet-visible spectral light absorption results of SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres. The SiO 2 @SiO 2 @TiO 2 microspheres can increase the absorption in the visible light region more than titanium dioxide through scattering. The CsPbBr 3 quantum dots have absorption in the wavelength range of 550 nm. After adding CsPbBr 3 perovskite quantum dots, the SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres all show a red shift phenomenon. The more the content of CsPbBr 3 perovskite quantum dots, the more obvious the red shift of the SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres, and more light is absorbed in the ultraviolet and visible light regions.

[0040] Example 3: Assembly and testing of a photoanode dye-sensitized solar cell 2 @SiO 2 @TiO 2 -CsPbBr 3 First, a slurry containing 0.5 mL of terpineol and 0.1 g of SiO

[0041] @SiO 2 @SiO 2 @TiO 2 -CsPbBr 3The mixed slurry of the hierarchical microsphere powder and P25 was dispersed and stirred for 30 minutes. SiO 3 @SiO 2 @TiO 2 @TiO 2 -CsPbBr 3 microsphere slurries with different CsPbBr 2 contents (2 wt%, 5 wt% and 10 wt%) were prepared respectively to obtain three composite slurries with different contents. Then, the obtained slurries were coated on a clean FTO plate with an area of 0.25 cm

[0042] Figure 7 by the blade coating method to form a uniform thin film. After drying and annealing at 450 °C for about 30 minutes, these photoanodes were respectively labeled as 2% microspheres, 5% microspheres and 10% microspheres. 36 mg of N719 dye was dissolved in 100 mL of ethanol and stirred in the dark for 24 h. The annealed photoanodes were placed in the N719 solution and soaked in the dark for 24 h. After that, the photoanodes were taken out and dried. The photoanode of the cell was used as the negative electrode, and the platinum counter electrode was used as the positive electrode. The photocurrent density-photovoltage curve of the cell was obtained by scanning under standard illumination.

[0042] Figure 7 The photocurrent density-photovoltage curves of the cells assembled based on 5 photoanode films are shown. The short-circuit current density and the conversion efficiency increased with the increase of the CsPbBr 3 doping amount, and then decreased with the further increase of the CsPbBr 3 content. The results show that the optimal content ratio is 5 wt%, which increases the short-circuit current density from 8.91 mA / cm 2 to 14.34 mA / cm 2 and the photogenerated conversion efficiency from 4.51% to 7.11%.

Claims

1. Inorganic perovskite CsPbBr 3 Quantum dots modified SiO 2 @SiO 2 @TiO 2 Preparation method of hierarchical microspheres It is characterized in that: Using SiO 2 @SiO 2 as the core layer, TiO 2 as the shell layer, and inorganic perovskite CsPbBr 3 quantum dot particles are modified on the shell layer and inside; the preparation method includes the following steps: Step 1: Take 3.3 mL of ammonia water, 9.9 mL of deionized water and 33.4 mL of ethanol, mix them in a beaker, then add 3.4 mL of tetraethyl orthosilicate and stir for 1 h; Take 1 / 8 volume of the mixed solution as the mother liquor, add 3.3 mL of ammonia water, 9.9 mL of deionized water and 33.4 mL of ethanol to the mother liquor, add 3.4 mL of tetraethyl orthosilicate, stir for 1 h, after the reaction is completed, centrifuge, wash and dry to obtain SiO 2 microspheres; Step 2: Weigh 0.2 g of the SiO prepared in Step 1 2 microspheres, 0.2 g of cetyltrimethylammonium bromide, 0.184 mL of isopropanol, and 0.12 g of urea are dispersed in 6 mL of deionized water. Add 0.056 mol of organic solvent and 0.2 mL of tetraethyl orthosilicate thereto, stir and disperse evenly at room temperature, then heat to 70 °C and react for 16 h. After the reaction is completed, centrifuge, wash, and dry, and then perform annealing treatment in a muffle furnace to obtain SiO 2 @SiO 2 microspheres; Step 3: Weigh 0.1 g of the SiO prepared in Step 2 2 @SiO 2 microspheres and disperse them in 17.5 mL of ethanol, 5.84 mL of acetonitrile and 0.17 mL of ammonia water. While stirring, add the mixed solution composed of ethanol, acetonitrile and tetrabutyl titanate into it. After reacting for 1 h, centrifuge, wash and dry, and then anneal in a muffle furnace to obtain SiO 2 @SiO 2 @TiO 2 microspheres; Step 4: Take 0.5 g Cs 2 CO 3 , 1.56 mL oleic acid and 18.75 mL octadecene are added to a three-necked flask, and heated to 130 °C under N 2 atmosphere and kept warm for 1 h, then the temperature is raised to 150 °C and maintained for 30 min to obtain a Cs precursor; 0.14 g PbBr 2 , 10 mL octadecene, 1 mL oleic acid, and 1 mL oleylamine are added to a three-necked flask, and heated to 130 °C under N 2 atmosphere and kept warm for 1 h until PbBr 2 is completely dissolved, then the temperature is raised to 165 °C and kept warm for 5 min, then 1 mL of the cesium precursor is quickly injected into the mixture, reacted for 5 s, the reaction is stopped in an ice-water bath, ethyl acetate is added to precipitate CsPbBr 3 , the product is obtained by centrifugation, washed with toluene, and dried in vacuo to obtain CsPbBr 3 perovskite quantum dots; Step 5: Weigh 1 - 5 mg of CsPbBr 3 perovskite quantum dots and disperse them in 10 mL of toluene. Then add 0.05 g of SiO 2 @SiO 2 @TiO 2 microspheres, stir overnight, centrifuge, and dry in vacuum at 70 °C to obtain SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 hierarchical microspheres.

2. The preparation method according to claim 1, It is characterized in that: In step 2, the organic solvent is selected from cyclohexane, benzene, and toluene.

3. The preparation method according to claim 2, It is characterized in that: The organic solvent is toluene.

4. The preparation method according to claim 1, It is characterized in that: In step 2, the annealing temperature is 550 °C and the annealing time is 2 h.

5. The preparation method according to claim 1, It is characterized in that: In step 3, the mixed solution is composed of 2.5 mL of ethanol, 0.83 mL of acetonitrile, and 0.42 - 0.58 mL of tetrabutyl titanate.

6. The preparation method according to claim 1, It is characterized in that: In step 3, the annealing temperature is 550 °C and the annealing time is 4 h.

7. CsPbBr prepared by the preparation method according to any one of claims 1-6 3 quantum dots modified with SiO 2 @SiO 2 @TiO 2 Application of the hierarchical microspheres It is characterized in that: The SiO 2 @SiO 2 @TiO 2 -CsPbBr 3 The hierarchical microspheres are used as a light absorber in the photoanode material. By taking advantage of the wide visible light absorption and the adjustable bandgap of CsPbBr 3 , the light absorption of the composite material is enhanced.

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