缺陷钝化获得高性能钙钛矿太阳能电池

Defect Passivation for High-Performance Perovskite Solar Cells

摘要: 本研究通过表面修饰与添加剂等策略，实现了钙钛矿薄膜体相及表面缺陷的有效调控，显著提升了反式结构器件的开路电压(V_OC)、填充因子(FF)、光电转换效率(PCE)及稳定性。基于硫氰酸胍(GuSCN)的界面钝化研究表明，该材料可优化钙钛矿/电子传输层界面特性，促进薄膜晶粒尺寸增大与结晶质量改善，进而增强载流子分离与输运能力。实验发现，GuSCN对宽带隙钙钛矿的改性效果尤为显著。结合[4-(3,6-二甲基-9H-咔唑-9-基)丁基]膦酸(Me-4PACz)对氧化镍/钙钛矿界面的修饰，器件PCE从18.51%提升至20.38%。进一步分析Gu⁺与SCN⁻的作用机制发现，Gu⁺的引入会提高器件电流密度(J_SC)同时加速钙钛矿薄膜降解，而SCN⁻通过前驱体溶液掺杂可同步优化FF与V_OC，使V_OC达1.20 V、FF达77.95%。尽管该策略仍存在J_SC偏低的局限性，但为缺陷选择性钝化提供了新思路。本研究通过缺陷调控策略，揭示了界面化学修饰与离子作用机制对器件性能的影响规律，为开发高效稳定的宽带隙钙钛矿电池奠定了重要实验基础。

Abstract: This study implements defect management strategies through passivation engineering, surface modification, and additive engineering, achieving effective control of bulk and surface defects in perovskite films. This approach significantly enhances the open-circuit voltage (V_OC), fill factor (FF), power conversion efficiency (PCE), and stability of inverted-structure devices. Interface passivation studies using guanidinium thiocyanate (GuSCN) demonstrate its capacity to optimize the perovskite/electron transport layer interface characteristics, promote grain growth, and improve crystallinity, thereby enhancing carrier separation and transport capabilities. Experimental results reveal that GuSCN modification exhibits particularly remarkable effects on wide-bandgap perovskites. Combined with [4-(3,6-dimethyl-9H-carbazol-9-yl) butyl] phosphonic acid (Me-4PACz) modification at the NiO_x/perovskite interface, the device PCE increased from 18.51% to 20.38%. Further analysis of the mechanism of Gu⁺ and SCN⁻ revealed that the introduction of Gu⁺ would increase the current density (J_SC) of the device while accelerating the degradation of the perovskite film, while SCN^- could simultaneously optimize FF and V_OC through doping in the precursor solution, achieving a V_OC of 1.20 V and an FF of 77.95%. Although this strategy still faces limitations in J_SC, it provides new insights into selective defect passivation. This work elucidates the impact mechanisms of interfacial chemical modification and ionic interactions on device performance through defect management strategies, establishing crucial experimental foundations for developing efficient and stable wide-bandgap perovskite solar cells.