Cyclopropenium (C3H3)+ as an Aromatic Alternative A‑Site Cation for Hybrid Halide Perovskite Architectures

Hybrid halide perovskites are an emerging class of photovoltaic materials, boasting high solar efficiencies from relatively simple preparations. However, the chemical diversity of the A-site organic cation is limited, generally due to steric constraints of the (PbI3)− cage. Herein we describe the use of a non-benzenoid Hückel aromatic, (C3H3)+, as a viable alternative to the readily employed methylammonium, formamidinium, and guanidinium A-site cations. (C3H3)+ may lead to greater moisture stability due to the lack of an acidic proton relative to the current (H–NR3)+-based systems while still boasting a narrow electronic band gap (Eg = 1.5 eV) and mobile holes and electrons (mh* = −1.27 and me* = 0.77, respectively).杂化卤化物钙钛矿（hybrid halide perovskites）是一类新兴光伏材料，凭借相对简便的制备工艺即可实现优异的太阳能转换效率。然而，受限于(PbI₃)⁻笼的空间位阻效应，A位有机阳离子的化学多样性较为有限。本文报道了将非苯型休克尔芳香族化合物(C₃H₃)⁺作为备选A位阳离子的研究，可替代当前广泛使用的甲胺阳离子、甲脒阳离子与胍阳离子。相较于当前基于(H–NR₃)⁺的体系，(C₃H₃)⁺因不含酸性质子，有望展现出更优的湿气稳定性；同时该体系仍具备较窄的电子带隙（Eg=1.5 eV），且空穴与电子均具有良好的迁移特性（有效质量分别为m_h*=-1.27和m_e*=0.77）。