赝卤素调控技术用于空气制备高效反式宽带隙无机钙钛矿光伏器件

Pseudo-halogen regulation technology for air preparation of high-efficiency inverted broadband gap inorganic perovskite photovoltaic devices

  • 摘要: 带隙 1.75–1.80 eV 的反式结构无机钙钛矿太阳电池,被看作全钙钛矿叠层器件顶部子电池的候选之一。不过相关叠层报道极少,根本原因是薄膜体内和表面密布非辐射复合中心,功率转换效率(Power conversion efficiency,PCE)难以继续提高。针对该瓶颈,本研究在前驱液中直接加入含赝卤素 CH3COO 的乙酸镉(cadmium acetate,Cd(CH3COO)2),利用 CH3COO 与铅离子的配位作用,精细调控钙钛矿的成核与晶体生长。与常规有机添加剂相比,Cd(CH3COO)2的有机部分占比极低,可在保持光热稳定性的也显著钝化缺陷、抑制非辐射复合。最终在空气环境中制备的反式宽带隙(1.75 eV)无机钙钛矿太阳电池获得 19.06% 的PCE,并且与未经Cd(CH3COO)2处理的器件相比,该器件展现出更优的湿、热、光多重稳定性。

     

    Abstract: Trans-structured inorganic perovskite solar cells with a band gap of 1.75-1.80 eV are considered as one of the candidates for the top sub-cells of all-perovskite tandem devices. However, there are few reports on the related lamination. The fundamental reason is that the power conversion efficiency (PCE) is difficult to continue to improve due to the dense non-radiative recombination centers in the bulk and surface of the film. In view of this bottleneck, cadmium acetate (Cd (CH3COO)2) containing pseudohalogen CH3COO was directly added to the precursor solution, and the coordination between CH3COO- and lead ions was used to finely regulate the nucleation and crystal growth of perovskite. Compared with conventional organic additives, the proportion of the organic part of Cd (CH3COO)2 is extremely low, which can also significantly passivate defects and inhibit non-radiative recombination while maintaining photothermal stability. Finally, the inverted wide band gap (1.75 eV) inorganic perovskite solar cell prepared in the air environment obtained 19.06 % PCE and compared with the device without Cd (CH3COO)2 treatment, the device showed better wet, heat and light multiple stability.

     

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