Enhancing performance and stability of CsPbBr3 perovskite solar cells through environmentally friendly binary solvent fabrication

CsPbBr 3 perovskite solar cells have garnered significant attention owing to their exceptional stability and facile fabrication in ambient conditions. Nonetheless, producing high-quality CsPbBr 3 thin films presents formidable challenges due to the intricate process and the employment of hazardous solvents. In this study, we propose a sustainable binary solvent system comprising water and absolute ethyl alcohol (EtOH) as a non-toxic substitute for the conventional toxic methanol employed as a CsBr solvent. Through modulation of the EtOH volume ratio in the binary solvent and implementation of a three-step spin-coating technique, defect-free, uniformly smooth, and exceptionally crystalline CsPbBr 3 thin films were effectively produced. The fabricated CsPbBr 3 thin films were employed in the construction of CsPbBr 3 perovskite solar cells. Experimental outcomes revealed that the CsPbBr 3 perovskite solar cells fabricated in the binary solvent system, with an EtOH volume ratio of 60%, attained an optimal photovoltaic conversion efficiency of 7.02%. Additionally, the architecture of the perovskite solar cells comprises FTO/c-TiO 2 /m-TiO 2 /CsPbBr 3 /carbon. Significantly, the device demonstrated exceptional humidity stability under ambient conditions, preserving 92% of its initial efficiency even after 30 days of testing. This study not only presents a straightforward approach for fabricating phase-pure CsPbBr 3 thin films but also contributes to the mitigation of toxic solvent usage during the fabrication of CsPbBr 3 perovskite solar cells.