Reconstruction of Hole-Selective Perovskite Contact Enables Highly Efficient Two-Step Perovskite Solar Cells via Improved Energetics

Perovskite solar cells (PSCs) via two-step sequential deposition represent one of the most promising upscaling photovoltaic technologies, yet their performance is critically constrained by deficient charge extraction and severe carrier losses at the contact. To tackle this key challenge, an efficient strategy is proposed to construct a highly efficient hole-selective perovskite contact using a novel additive, 4-nitro-2-(trifluoromethyl)benzonitrile (NTFB). The incorporation of NTFB effectively promotes the sequential crystallization dynamics and concurrently reconfigures the perovskite energetics, enabling an excellent contact with upper hole transport layer, characterized by reduced morphological defects and a homogeneous energetic landscape. This highly efficient contact facilitates superior hole extraction while effectively blocking electrons, thereby minimizing interfacial nonradiative recombination and extending the quasi-Fermi-level splitting. As a result, the target device exhibits a markedly improved performance, with power conversion efficiency increasing from 22.61% to 25.10%, along with enhanced stability under continuous maximum power point operation. This work provides a facile method for constructing highly charge-selective contacts to minimize charge carrier loss and further advance perovskite solar cell technology.