Highly Efficient Ruddlesden–Popper Halide Perovskite PA₂MA₄Pb₅I₁₆ Solar Cells

Abstract

Two-dimensional (2D) Ruddlesden–Popper (RP) organic–inorganic perovskites have emerged as promising candidates for solar cells with technologically relevant stability. Herein, a new RP perovskite, the fifth member (⟨<i>n</i>⟩ = 5) of the (CH₃(CH₂)₂NH₃)₂(CH₃NH₃)_<i>n</i>−1Pb_<i>n</i>I_3<i>n</i>+1 family (abbreviated as PA₂MA₄Pb₅I₁₆), was synthesized and systematically investigated in terms of photovoltaic application. The obtained pure PA₂MA₄Pb₅I₁₆ crystal exhibits a direct band gap of <i>E</i>_g = 1.85 eV. Systematic analysis on the solid film highlights the key role of the precursor–solvent interaction in the quantum well orientation, phase purity, grain size, surface quality, and optoelectronic properties, which can be well-tuned with addition of dimethyl sulfoxide (DMSO) into the <i>N</i>,<i>N</i>-dimethylformamide (DMF) precursor solution. These findings present opportunities for designing a high-quality RP film with well-controlled quantum well orientation, micrometer-sized grains, and optoelectronic properties. As a result, we achieved power conversion efficiency (PCE) up to 10.41%