Organic interlayer for enhanced buried interfaces in wide-bandgap perovskite solar cells.

Achieving high performance and stability in wide-bandgap perovskite solar cells (PSCs) is essential for the development of tandem solar cells capable of surpassing the theoretical efficiency limit of single-junction photovoltaic devices. However, the performance of wide-bandgap PSCs remains challenging, primarily due to non-radiative recombination at the interfaces. An interlayer applied at the buried interface between the hole transport layer (HTL) and the perovskite in a p-i-n architecture can play a pivotal role, as it is critical for efficient charge transport, extraction, and the formation of high-quality perovskite films. In this work, we introduce a donor-acceptor architectural quinoxaline-based organic interlayer specifically designed for the interface between NiOx and wide-bandgap perovskite. The incorporation of this interlayer effectively passivates defects at the perovskite interface, leading to improved charge carrier extraction and a substantial reduction in non-radiative recombination, while also enhancing the overall quality of the perovskite film. Moreover, the high dipole moment of QxNN increases the built-in potential of the device, further contributing to enhanced charge extraction. Notably, PSCs incorporating the organic interlayer exhibited a remarkable increase in power conversion efficiency (PCE), from 17.5% to 20.0%, while maintaining their performance over 500 hours under ambient conditions.