Inverted perovskite solar cells with N-type organic small molecule dopant optimization

The interface contact properties, charge recombination behavior, and energy level alignment of inverted perovskite solar cells (PSCs) constitute core bottlenecks that restrict their performance improvement and commercialization. Developing electronic transport layer (ETL) materials with superior efficiency and stability represents a crucial technological approach to overcoming these limitations. This study designed and synthesized a novel N-type organic small molecule named SMX2, which was introduced into [6,6]-phenyl-C61-butyric acid methyl ester to construct a composite ETL. Experimental results confirm that SMX2 can improve the interfacial compatibility and contact quality at the ETL-perovskite interface, optimize energy level alignment, passivate defects, and reduce non-radiative recombination. The champion device based on the SMX2-doped ETL achieves a power conversion efficiency of 20.06%. After storage in air for 30 days without encapsulation, the device maintains 92.8% of its initial efficiency. This work provides a valuable theoretical basis and experimental guidance for developing simple and highly effective ETL modification materials, holding significant implications for advancing the development of high-performance and long-lifetime PSCs.