Improvement of Thermal Stability and Photoelectric Performance of Cs2PbI2Cl2/CsPbI2.5Br0.5 Perovskite Solar Cells by Triple-Layer Inorganic Hole Transport Materials

• Published in: Nanomaterials (Basel, Switzerland) Vol. 14; no. 9; p. 742
• Main Authors: Liu, Yu, Li, Bicui, Xu, Jia, Yao, Jianxi
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.05.2024
• Subjects: Cobalt oxides; Corrosion; CuSCN hole transport layer; Efficiency; Energy conversion efficiency; Environmental factors; Hole mobility; Low conductivity; Measurement techniques; Mobility; perovskite solar cell; Perovskites; Phase transitions; Photoelectricity; Photovoltaic cells; Photovoltaics; sandwich structure; Sandwich structures; Solar cells; solvent resistance; Solvents; Spectrum analysis; Stability; Temperature; Thermal stability; Thiocyanates; United Kingdom > UK; Japan
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano14090742

Conventional hole transport layer (HTL) Spiro-OMeTAD requires the addition of hygroscopic dopants due to its low conductivity and hole mobility, resulting in a high preparation cost and poor device stability. Cuprous thiocyanate (CuSCN) is a cost-effective alternative with a suitable energy structure and high hole mobility. However, CuSCN-based perovskite solar cells (PSCs) are affected by environmental factors, and the solvents of an HTL can potentially corrode the perovskite layer. In this study, a Co3O4/CuSCN/Co3O4 sandwich structure was proposed as an HTL for inorganic Cs2PbI2Cl2/CsPbI2.5Br0.5 PSCs to address these issues. The Co3O4 layers can serve as buffer and encapsulation layers, protecting the perovskite layer from solvent-induced corrosion and enhancing hole mobility at the interface. Based on this sandwich structure, the photovoltaic performances of the Cs2PbI2Cl2/CsPbI2.5Br0.5 PSCs are significantly improved, with the power conversion efficiency (PCE) increasing from 9.87% (without Co3O4) to 11.06%. Furthermore, the thermal stability of the devices is also significantly enhanced, retaining 80% of its initial PCE after 40 h of continuous aging at 60 °C. These results indicate that the Co3O4/CuSCN/Co3O4 sandwich structure can effectively mitigate the corrosion of the perovskite layer by solvents of an HTL and significantly improves the photovoltaic performance and thermal stability of devices.