بررسي عملكرد سلول¬هاي خورشيدي پروسكايتي برپايه ساختار اپال معكوس تيتانيا در شكافت فوتوالكتروشيميايي آب

Due to the increasing reliance on fossil fuels, significant attention has been directed toward enhancing the efficiency of solar energy as a renewable source. Among photovoltaic technologies, perovskite solar cells have garnered interest for achieving high efficiency with relatively low production costs. Concurrently, photoelectrochemical water splitting offers a clean and sustainable method for hydrogen production. This process uses solar energy to split water into hydrogen and oxygen, positioning hydrogen as a promising clean fuel. One of the most promising perovskites for water splitting is mineral halide perovskite CsPbBr3; however, this material has limitations, such as minimal light absorption in the visible region and instability when exposed to water molecules. To address these issues, the integration of titanium dioxide (TiO2) reverse opal structures with CsPbBr3 perovskites has been explored to enhance light absorption, leveraging the unique structure of reverse opal TiO2. In this study, inverted opal layers were employed to improve optical efficiency. Structural modifications to the electron transfer layer further increased light transmission, thereby enhancing the efficiency of light collection by the perovskite. Specifically, mesoporous TiO2 layers in both regular and irregular forms were fabricated and eva‎luated as electron transfer layers using spin-coating and immersion deposition methods. The results demonstrated that structured layers with regular pores exhibited superior performance compared to non-molded porous layers, owing to better integration with the reverse opal layer and enhanced optical transmission. To improve the stability of perovskite in the presence of water, a protective carbon-based hole transport layer, composed of graphite, carbon black, and binder, was selected. The fabricated layers were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), contact angle measurements, UV-visible spectroscopy, and sheet resistance analysis. Following this, the performance of the developed structures in both perovskite solar cells and photoelectrochemical water splitting was investigated. To further enhance performance and increase the overvoltage required for water splitting, the best-designed photoelectrodes were coupled with a silicon solar module. The highest short-circuit photocurrent density of 18.4 mA/cm² was obtained in a solar cell with a TiO2 inverse opal layer and an irregular porous layer, while the lowest short-circuit current of 1.99 mA/cm² was recorded for structures lacking the inverse opal layer. To improve the connection between the reverse opal layer and the electron transfer layer, both regular and irregular mesoporous TiO2 structures were tested. The electron transfer layer with regular pores, prepared via immersion, achieved the highest short-circuit current density of 6.03 mA/cm² and an efficiency of 5.32%. In the context of photoelectrochemical water splitting, the highest photocurrent of 6.38 mA/cm² at 1.23 V vs. the reversible hydrogen electrode (RHE) was achieved using a TiO2 inverse opal structure on a regular mesoporous substrate, prepared by the immersion method. Finally, the photoelectrodes developed for water splitting were coupled with the silicon solar module, resulting in a maximum photocurrent of 10.75 mA/cm² at zero voltage and 56.90 mA/cm² at VRHE = 1.23 V. These results represent the best performance reported to date for CsPbBr3 perovskite structures used in photoelectrochemical water splitting.

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