Interfacial Characteristics of Gallium-Indium Liquid Metal as Counter Electrode for Flexible Perovskite Solar Cells
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초록
내용
Perovskite solar cells (PSCs) have emerged as a promising photovoltaic device, but developing flexible PSCs remains challenging. For example, solid metals used as counter electrodes can fatigue during repeated bending, which can degrade the performance. For flexible PSCs, liquid metal can be an alternative to conventional solid metal electrodes. Here, gallium-indium alloy liquid metal (EGaIn) was used as a counter electrode for PSCs. The photovoltaic characteristics highly depending on the presence of gallium oxide on the surface of EGaIn. To elucidate this phenomenon, we assumed that gallium oxide acts as a barrier to prevent the metal diffusion into the perovskite layer, while facilitating electron transfer. This hypothesis was confirmed by a comprehensive analysis using EDS, SCLC, EIS, and TRPL measurements. Finally, we fabricated a flexible PSC based on the liquid metal counter electrode and confirmed that the device maintains stable performance under repeated bending cycles.