The fabrication of multidimensional organometallic halide perovskite via a low‐pressure vapor‐assisted solution process is demonstrated for the first time. Phenyl ethyl‐ammonium iodide (PEAI)‐doped lead iodide (PbI₂) is first spin‐coated onto the substrate and subsequently reacts with methyl‐ammonium iodide (MAI) vapor in a low‐pressure heating oven. The doping ratio of PEAI in MAI‐vapor‐treated perovskite has significant impact on the crystalline structure, surface morphology, grain size, UV–vis absorption and photoluminescence spectra, and the resultant device performance. Multiple photoluminescence spectra are observed in the perovskite film starting with high PEAI/PbI₂ ratio, which suggests the coexistence of low‐dimensional perovskite (PEA₂MA_n−1Pb_nI_3n+1) with various values of n after vapor reaction. The dimensionality of the as‐fabricated perovskite film reveals an evolution from 2D, hybrid 2D/3D to 3D structure when the doping level of PEAI/PbI₂ ratio varies from 2 to 0. Scanning electron microscopy images and Kelvin probe force microscopy mapping show that the PEAI‐containing perovskite grain is presumably formed around the MAPbI₃ perovskite grain to benefit MAPbI₃ grain growth. The device employing perovskite with PEAI/PbI₂ = 0.05 achieves a champion power conversion efficiency of 19.10% with an open‐circuit voltage of 1.08 V, a current density of 21.91 mA cm⁻², and a remarkable fill factor of 80.36%.

中文翻译：

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通过低压蒸汽辅助溶液处理工艺实现的高效2D / 3D混合钙钛矿太阳能电池

首次演示了通过低压蒸气辅助溶液法制备多维有机金属卤化物钙钛矿。首先将掺杂有苯基乙基碘化碘（PEAI）的碘化铅（PbI ₂）旋涂到基材上，然后在低压加热炉中与甲基碘化碘（MAI）蒸气发生反应。MAI汽化钙钛矿中PEAI的掺杂比例对晶体结构，表面形貌，晶粒尺寸，UV-vis吸收和光致发光光谱以及由此产生的器件性能具有重大影响。从高PEAI / PbI ₂比率开始，钙钛矿薄膜中观察到了多个光致发光光谱，这表明低维钙钛矿（PEA ₂ MA气相反应后， n的值分别为_{n -1} Pb _n I _{3 n +1}）。当PEAI / PbI ₂的掺杂水平从2变为0时，制成的钙钛矿薄膜的尺寸揭示了从2D，混合2D / 3D到3D结构的演变。扫描电子显微镜图像和Kelvin探针力显微镜图显示：大概在MAPbI ₃钙钛矿晶粒周围形成了含PEAI的钙钛矿晶粒，从而有利于MAPbI ₃晶粒的生长。使用钙钛矿和PEAI / PbI _2的设备= 0.05时，具有1.08 V的开路电压，21.91 mA cm ^-2的电流密度和显着的填充系数80.36％，可实现19.10％的最佳功率转换效率。