Perovskite photovoltaics advance rapidly, but questions remain regarding point defects: while experiments have detected the presence of electrically active defects no experimentally confirmed microscopic identifications have been reported. Here we identify lead monovacancy (V_Pb) defects in MAPbI₃ (MA = CH₃NH₃⁺) using positron annihilation lifetime spectroscopy with the aid of density functional theory. Experiments on thin film and single crystal samples all exhibited dominant positron trapping to lead vacancy defects, and a minimum defect density of ~3 × 10¹⁵ cm⁻³ was determined. There was also evidence of trapping at the vacancy complex \(({{{{{\rm{V}}}}}}_{{{{{\rm{Pb}}}}}}{{{{{\rm{V}}}}}}_{{{{{\rm{I}}}}}})^{-}\) in a minority of samples, but no trapping to MA-ion vacancies was observed. Our experimental results support the predictions of other first-principles studies that deep level, hole trapping, \({{{{{{\rm{V}}}}}}}_{{{{{{\rm{Pb}}}}}}}^{2-}\), point defects are one of the most stable defects in MAPbI₃. This direct detection and identification of a deep level native defect in a halide perovskite, at technologically relevant concentrations, will enable further investigation of defect driven mechanisms.

钙钛矿光伏发展迅速，但关于点缺陷的问题仍然存在：虽然实验已检测到电活性缺陷的存在，但尚未有实验证实的微观鉴定报告。在这里，我们借助密度泛函理论，使用正电子湮灭寿命光谱来识别 MAPbI ₃ (MA = CH ₃ NH ₃ ⁺ ) 中的铅单空位 (V _Pb ) 缺陷。对薄膜和单晶样品的实验均表现出主要的正电子捕获导致空位缺陷，并且确定了约3×10 ¹⁵ cm ^-3的最小缺陷密度。也有证据表明在空位复合体\(({{{{{\rm{V}}}}}}_{{{{{\rm{Pb}}}}}}{{{{{\ rm{V}}}}}}_{{{{{\rm{I}}}}}})^{-}\)在少数样品中，但没有观察到 MA 离子空位的捕获。我们的实验结果支持其他第一性原理研究的预测，即深能级、空穴捕获、 \({{{{{{\rm{V}}}}}}}_{{{{{\rm{Pb} }}}}}}^{2-}\) ，点缺陷是 MAPbI ₃中最稳定的缺陷之一。这种在技术相关浓度下直接检测和识别卤化物钙钛矿中深层天然缺陷的方法，将使对缺陷驱动机制的进一步研究成为可能。