Hu Zhaosheng, Wang Zhen, Kapil Gaurav, Ma Tingli, Iikubo Satoshi, Minemoto Takashi, Yoshino Kenji, Toyoda Taro, Shen Qing, Hayase Shuzi
Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Waka-matsu-ku, Kitakyushu, 808-0196, Japan.
Department of Electrical and Electronic Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga, 525-8577, Japan.
ChemSusChem. 2018 Sep 11;11(17):2930-2935. doi: 10.1002/cssc.201800815. Epub 2018 Jul 26.
Bismuth-based solar cells have been under intensive interest as an efficient non-toxic absorber in photovoltaics. Within this new family of semiconductors, we herein report a new, long-term stable copper bismuth iodide (CuBiI ). A solutionprocessed method under air atmosphere is used to prepare the material. The adopted HI-assisted dimethylacetamide (DMA) co-solvent can completely dissolve CuI and BiI powders with high concentration compared with other organic solvents. Moreover, the high vapor pressure of tributyl phosphate, selected for the solvent vapor annealing (SVA), enables complete low-temperature (≤70 °C) film preparation, resulting in a stable, uniform, dense CuBiI film. The average grain size increases with the precursor concentration, greatly improving the photoluminescence lifetime and hall mobility; a carrier lifetime of 3.03 ns as well as an appreciable hall mobility of 110 cm V s were obtained. XRD illustrates that the crystal structure is cubic (space group Fd3m) and favored in the [1 1 1] direction. Moreover, the photovoltaic performance of CuBiI was also investigated. A wide bandgap (2.67 eV) solar cell with 0.82 % power conversion efficiency is presented, which exhibits excellent long-term stability over 1008 h under ambient conditions. This air-stable material may give an application in future tandem solar cells as a stable short-wavelength light absorber.
铋基太阳能电池作为光伏领域一种高效无毒的吸收体，一直备受关注。在这个新型半导体家族中，我们在此报告一种新型的、长期稳定的碘化铜铋（CuBiI）。采用空气气氛下的溶液处理方法来制备该材料。与其他有机溶剂相比，所采用的HI辅助二甲基乙酰胺（DMA）共溶剂能够以高浓度完全溶解CuI和BiI粉末。此外，用于溶剂气相退火（SVA）的磷酸三丁酯的高蒸气压能够在低温（≤70°C）下完成薄膜制备，从而得到稳定、均匀、致密的CuBiI薄膜。平均晶粒尺寸随前驱体浓度增加而增大，极大地提高了光致发光寿命和霍尔迁移率；获得了3.03 ns的载流子寿命以及110 cm² V⁻¹ s⁻¹的可观霍尔迁移率。XRD表明晶体结构为立方晶系（空间群Fd3m）且在[1 1 1]方向上择优生长。此外，还研究了CuBiI的光伏性能。展示了一种带隙较宽（2.67 eV）、功率转换效率为0.82%的太阳能电池，该电池在环境条件下1008小时内表现出优异的长期稳定性。这种空气稳定的材料未来可能作为稳定的短波长光吸收体应用于串联太阳能电池中。
