Zhu Huimin, Pan Mingao, Johansson Malin B, Johansson Erik M J
Department of Chemistry- Ångström, Div. Physical Chemistry, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden.
ChemSusChem. 2017 Jun 22;10(12):2592-2596. doi: 10.1002/cssc.201700634. Epub 2017 Jun 1.
Here, a lead-free silver bismuth iodide (AgI/BiI ) with a crystal structure with space group R3‾ m is investigated for use in solar cells. Devices based on the silver bismuth iodide deposited from solution on top of TiO and the conducting polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) as a hole-transport layer are prepared and the photovoltaic performance is very promising with a power conversion efficiency over 2 %, which is higher than the performance of previously reported bismuth-halide materials for solar cells. Photocurrent generation is observed between 350 and 700 nm, and the maximum external quantum efficiency is around 45 %. The results are compared to solar cells based on the previously reported material AgBi I , and we observe a clearly higher performance for the devices with the new silver and bismuth iodides composition and different crystal structure. The X-ray diffraction spectrum of the most efficient silver bismuth iodide material shows a hexagonal crystal structure with space group R3‾ m, and from the light absorption spectrum we obtain an indirect band gap energy of 1.62 eV and a direct band gap energy of 1.85 eV. This report shows the possibility for finding new structures of metal-halides efficient in solar cells and points out new directions for further exploration of lead-free metal-halide solar cells.
在此，对一种具有空间群为R3‾m晶体结构的无铅碘化银铋（AgI/BiI ）进行了太阳能电池应用研究。制备了基于从溶液中沉积在TiO顶部的碘化银铋以及作为空穴传输层的导电聚合物聚（3 - 己基噻吩 - 2,5 - 二基）（P3HT）的器件，其光伏性能非常有前景，功率转换效率超过2%，高于先前报道的用于太阳能电池的卤化铋材料的性能。在350至700 nm之间观察到光电流产生，最大外部量子效率约为45%。将结果与基于先前报道的材料AgBiI 的太阳能电池进行比较，我们观察到具有新的碘化银和铋组成及不同晶体结构的器件性能明显更高。最有效的碘化银铋材料的X射线衍射光谱显示出具有空间群为R3‾m的六方晶体结构，并且从光吸收光谱中我们获得间接带隙能量为1.62 eV，直接带隙能量为1.85 eV。本报告展示了在太阳能电池中找到高效金属卤化物新结构的可能性，并指出了无铅金属卤化物太阳能电池进一步探索的新方向。
