Dendritic growth lowers carbon electrode work function for efficient perovskite solar cells

A major challenge in the development of printable mesoscopic perovskite solar cells (p-MPSCs) is the modifi-cation of the carbon electrode's work function to facilitate holes extraction and transport in carbon-based hole transport layer (HTL)-free devices. To address this, we present an innovative approach: in-situ polymerization of aniline on nano-graphite's surface, followed by carbonization, forming a dendritic structure. The modified carbon electrode exhibits reduced work function from-5.06 eV to-5.19 eV and improved energy level alignment with perovskite, facilitating charge collection and significantly enhancing hole collection. This results in a photovoltaic conversion efficiency increase from 15.16 % to 18.19 % in p-MPSCs. Furthermore, the modified carbon electrode-based p-MPSCs exhibit exceptional stability, maintaining high power conversion efficiency even after 10,000-h air exposure without encapsulation. Our work presents a vital strategy for improving photovoltaic conversion characteristics and stability of p-MPSCs through carbon electrode interface modification.

Automated summary

This study presents an innovative approach to improve the photovoltaic conversion characteristics and stability of perovskite solar cells through carbon electrode interface modification. By in-situ polymerization and carbonization on the surface of nano-graphite, a dendritic structure carbon electrode is formed, reducing the work function and aligning the energy levels with perovskite. This leads to improved charge and hole collection efficiency, resulting in increased photovoltaic conversion efficiency. Furthermore, the modified carbon electrode-based perovskite solar cells exhibit exceptional stability, maintaining high efficiency even without encapsulation.