Quantum-Assisted Photoelectric Effects in Perovskite Solar Cells

通过定制化尺寸工程生产的价带不断上移的梯度二维钙钛矿盖壳，可以有效地从三维钙钛矿岩心中提取孔洞。电子结构的实空间观测将充分揭示二维/三维混合钙钛矿太阳能电池（PSCs）的运行机制。在本财政年度，光调制扫描隧道显微镜显示了2D (C4H9NH3)2(CH3NH3)n-1PbnI3n+1/3D CH3NH3PbI3堆叠钙钛矿的横截面波段排列。通过系统地分析它们的电子构型，可以在空间上分辨出垂直三维到二维方向上的钙钛矿混合维带结构。值得注意的是，光照条件下二维钙钛矿中的电场比黑暗条件下更大，导致二维和三维钙钛矿中分布的空穴和电子浓度分别增加。受益于这种电子重构，电荷复合被抑制，从而显著提高了2D/3D PSC性能。此外，我们的方法为光电器件能级的直接局部映射开辟了一条途径。（纳米能源，2021,89,106362）

Graded 2D perovskite capping shells with continuously upshifting valence bands, produced by tailored dimensional engineering, can effectively extract holes from 3D perovskite cores. Real-space observation of electronic structures will fully reveal the operating mechanisms of 2D/3D hybrid perovskite solar cells (PSCs). In this financial year, the light-modulated scanning tunneling microscopy visualizes the cross-sectional band alignment across 2D (C4H9NH3)2(CH3NH3)n-1PbnI3n+1/3D CH3NH3PbI3 stacked perovskites. By systematically analyzing their electronic configuration, the mixed-dimensional perovskite band structure along the vertical 3D-to-2D direction can be spatially resolved. Remarkably, the electric field in the 2D perovskite is larger under light illumination than under dark conditions, resulting in an increase in the concentration of holes and electrons distributed in the 2D and 3D perovskites, respectively. Benefiting from this electronic reconstruction, charge recombination is suppressed, thereby significantly promoting the 2D/3D PSC performance. Moreover, our method opens an avenue for direct, local mapping of optoelectronic device energy levels. (Nano Energy, 2021, 89, 106362)