Strategy for the isomerization of dibenzo[b,d]furan-based carbazole derivatives as hole transporting materials for perovskite solar cells: theoretical design and experimental study

Abstract

The structural design of hole transport materials (HTMs) is a crucial approach to improving the efficiency and stability of perovskite solar cells (PSCs). In this study, a series of isomeric dibenzo[b,d]furan-based carbazole derivatives (CX11–CX14) were designed to provide a design strategy for the development of HTMs in PSC applications. Side chain isomerism has a significant impact on molecular conjugation, exhibiting distinct isomer-dependent effects in terms of energy levels, planarity, dipole moment, and hole mobility. Furthermore, theoretical calculations and experimental results indicate that the molecule CX11 with superior hole mobility and stronger adsorption on the perovskite surface can act as a potential HTM for PSC applications. According to the results of the optimized PSC devices, the power conversion efficiency (PCE) of the CX11-based PSC exceeded 23%, which is higher than that of devices based on other molecules. The close agreement between computational predictions and experimental validation not only validates the theoretical framework for designing molecular isomers of HTMs but also provides crucial molecular-level insights. The demonstrated methodology is expected to motivate researchers to develop even more efficient HTM isomers for PSCs with higher PCEs.