Zhang Xinyu, Li Ziqing, Hong Enliu, Yan Tingting, Fang Xiaosheng
Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200438, P. R. China.
State Key Laboratory of Photovoltaic Science and Technology, Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and Perception, Institute of Optoelectronics, Fudan University, Shanghai, 200438, P. R. China.
Adv Mater. 2025 Jan;37(3):e2412014. doi: 10.1002/adma.202412014. Epub 2024 Nov 17.
Ruddlesden-Popper quasi-2D perovskites represent robust candidates for optoelectronic applications, achieving a delicate balance between outstanding photoresponse and stability. However, mitigating the internal defects in polycrystalline films remains challenging, and their optoelectronic performances still lag behind that of their 3D counterparts. This work highlights the profound impact of defect passivation at the buried interface and grain boundaries through a dual-cation-release strategy. Cations released from the pre-deposited inorganic iodide buffer layer effectively repair deep-level defects by inducing low-dimensional phase reconstruction and interacting with undercoordinated ions. The resulting quasi-2D perovskite polycrystalline films feature large grain size (>2 µm) and minimum surface roughness, along with alleviated out-of-plane residual tensile strain, which is beneficial for inhibiting the initiation and propagation of cracks. The fabricated photodetector demonstrates drastically improved self-powered photoresponse capability, with maximum responsivity up to 0.41 A W at 430 nm and an ultrafast response speed of 161 ns / 1.91 µs. Moreover, this strategy is compatible with the photolithography-assisted hydrophobic-hydrophilic patterning process for fabricating pixelated photodetector arrays, which enables high-sensitivity imaging. This study presents a feasible defect passivation approach in quasi-2D perovskites, thereby providing insights into the fabrication of high-performance optoelectronic devices.
Ruddlesden-Popper准二维钙钛矿是光电子应用的有力候选材料，在出色的光响应和稳定性之间实现了微妙的平衡。然而，减轻多晶薄膜中的内部缺陷仍然具有挑战性，并且它们的光电子性能仍落后于三维同类材料。这项工作通过双阳离子释放策略突出了掩埋界面和晶界处缺陷钝化的深远影响。从预沉积的无机碘化物缓冲层释放的阳离子通过诱导低维相重构并与配位不足的离子相互作用，有效地修复了深层缺陷。所得的准二维钙钛矿多晶薄膜具有大晶粒尺寸（>2 µm）和最小表面粗糙度，同时减轻了面外残余拉伸应变，这有利于抑制裂纹的萌生和扩展。所制备的光电探测器展示出大幅提高的自供电光响应能力，在430 nm处的最大响应度高达0.41 A/W，响应速度超快，为161 ns / 1.91 µs。此外，该策略与用于制造像素化光电探测器阵列的光刻辅助疏水-亲水图案化工艺兼容，从而实现高灵敏度成像。这项研究提出了一种在准二维钙钛矿中可行的缺陷钝化方法，从而为高性能光电器件的制造提供了见解。
