High-quality NiO<sub>x</sub> nanoparticles synthesized via low temperature chemical precipitation method for high-performance inverted perovskite photovoltaics.

Liu, Ziyuan; He, Dongmei; Zhang, Zuolin; Zhang, Kun; Tang, Ziyi; Gong, Shaokuan; He, Xilai; Liu, Xinxing et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Dual hole transport layers consisting of NiO<sub>x</sub> and self-assembled molecules are widely adopted in inverted perovskite solar cells, yet plagued by high impurity content, inefficient hole transport, low molecular coverage, weak interfacial binding, unstable buried interface and energy level mismatch. Herein, a low-temperature chemical precipitation strategy is developed to synthesize high-quality NiO<sub>x</sub> nanoparticles as hole transport layers. Compared with the room-temperature route, the low-temperature prepared NiO<sub>x</sub> films deliver an elevated Ni<sup>3+</sup>/Ni<sup>2+</sup> ratio, reduced impurities, higher electrical conductivity and hole mobility. Moreover, this strategy improves molecular coverage, alleviates energy level mismatch, accelerates hole extraction and strengthens buried interface stability. The optimized cells achieve a certified power conversion efficiency of 27.1%, and the 14 cm<sup>2</sup> minimodule reaches an efficiency of 23.18%. The devices retain 91.5% efficiency after 2100 h of continuous operation, and 91.4% efficiency after 2000 h of damp-heat aging.