Fabrication and performance study of semi-transparent perovskite solar cells for photovoltaic windows

To accelerate energy-saving and carbon-reduction efforts in the building sector, semi-transparent perovskite photovoltaic windows, which combine power generation with indoor light and heat regulation, have emerged as a highly promising solution for building-integrated photovoltaics. However, most existing studies focus on the fabrication and optimization of small-area (<1 cm²) devices under standard laboratory conditions, while a systematic evaluation of their integrated “optical-thermal-electrical” characteristics under real and dynamic environments remains lacking. In this study, 15 cm² series-connected semi-transparent perovskite solar cells are successfully fabricated. Under standard test conditions, these devices achieve a power conversion efficiency of 3.57%, an average visible transmittance of 38.4%, and a color rendering index as high as 94. Indoor comparative experiments reveal that the devices in the “photoelectric mode” can achieve an average active-cooling effect of 1.81 °C compared to the “photothermal mode.” Further outdoor tests using a multi-tilt-angle platform (0°, 30°, 60°, 90°) show that the device at 30° tilt yielded the highest daily cumulative energy generation, reaching 1.211 MJ/m². Performance analysis indicated that outdoor operation can be divided into two characteristic phases: a “normal stage” dominated by temperature-induced degradation, where the efficiency exhibits a negative true temperature coefficient; and a “degradation stage” where light-induced degradation occurs, leading to a positive true temperature coefficient. Moreover, during the “normal stage” under diffuse-light-dominant conditions, the power conversion efficiency of the devices generally exceeds standard test values. This study provides important experimental evidence for the fabrication, performance evaluation, and optimization of semi-transparent perovskite photovoltaic windows for practical building applications.