Heat-dissipation regulation for improving the thermal stability and efficiency of planar perovskite solar cells

Abstract

Perovskite solar cells (PSCs) have emerged as promising next-generation photovoltaics owing to their excellent power conversion efficiency (PCE). However, their poor thermal stability, originating from insufficient thermal transfer, is still an obstacle to their further commercialization. Herein, an effective heat-dissipation strategy was developed by incorporating a two-dimensional (2D) polymeric semiconductor, graphitic carbon nitride (g-C₃N₄) nanosheets, into the electron-transport layer (ETL) and perovskite absorber layer. We present g-C₃N₄ nanosheets as a thermal transfer pathway to dissipate the heat accumulated inside the device to alleviate its efficiency drop. In particular, we observed that the 2D g-C₃N₄ could effectively lower the device temperature and restrain thermally induced morphological degradation from the top surface and buried interface. Moreover, the g-C₃N₄ facilitated electron extraction from the perovskite to the ETL and reduced interfacial charge recombination. As a result, the unencapsulated device achieved an improved efficiency of 24.19% with substantially improved thermal stability, retaining 70% of its initial efficiency after aging at 65 °C for 1000 h. This work demonstrates the importance of heat dissipation in realizing the long-term stability of PSCs.