Oh Jae Taek, Kim Dae-Hwan, Kim Younghoon
Convergence Research Center for Solar Energy, Daegu Gyeongbuk Institute of Science and Technology (DGIST); Department of Chemistry and Research Institute for Convergence of Basic Sciences, Hanyang University.
Convergence Research Center for Solar Energy, Daegu Gyeongbuk Institute of Science and Technology (DGIST).
J Vis Exp. 2018 Sep 27(139):58286. doi: 10.3791/58286.
Bismuth-based hybrid perovskites are regarded as promising photo-active semiconductors for environment-friendly and air-stable solar cell applications. However, poor surface morphologies and relatively high bandgap energies have limited their potential. Silver-bismuth-iodine (Ag-Bi-I) is a promising semiconductor for optoelectronic devices. Therefore, we demonstrate the fabrication of Ag-Bi-I ternary thin films using material solution processing. The resulting thin films exhibit controlled surface morphologies and optical bandgaps according to their thermal annealing temperatures. In addition, it has been reported that Ag-Bi-I ternary systems crystallize to AgBi2I7, Ag2BiI5, etc. according to the ratio of the precursor chemicals. The solution-processed AgBi2I7 thin films exhibit a cubic-phase crystal structure, dense, pinhole-free surface morphologies with grains ranging in size from 200 to 800 nm, and an indirect bandgap of 1.87 eV. The resultant AgBi2I7 thin films show good air stability and energy band diagrams, as well as surface morphologies and optical bandgaps suitable for lead-free and air-stable single-junction solar cells. Very recently, a solar cell with 4.3% power conversion efficiency was obtained by optimizing the Ag-Bi-I crystal compositions and solar cell device architectures.
铋基混合钙钛矿被认为是用于环保且空气稳定的太阳能电池应用的有前景的光活性半导体。然而，较差的表面形貌和相对较高的带隙能量限制了它们的潜力。银铋碘（Ag-Bi-I）是一种用于光电器件的有前景的半导体。因此，我们展示了使用材料溶液处理制备Ag-Bi-I三元薄膜的方法。所得薄膜根据其热退火温度呈现出可控的表面形貌和光学带隙。此外，据报道，Ag-Bi-I三元体系会根据前驱体化学物质的比例结晶为AgBi2I7、Ag2BiI5等。溶液处理的AgBi2I7薄膜呈现立方相晶体结构，表面形貌致密、无针孔，晶粒尺寸在200至800纳米之间，间接带隙为1.87电子伏特。所得的AgBi2I7薄膜表现出良好的空气稳定性和能带图，以及适合无铅且空气稳定的单结太阳能电池的表面形貌和光学带隙。最近，通过优化Ag-Bi-I晶体组成和太阳能电池器件结构，获得了功率转换效率为4.3%的太阳能电池。
