Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, College of Physics and Energy, Fujian Normal University, Fuzhou, 350117, China.
Nanoscale. 2019 Feb 28;11(9):3968-3978. doi: 10.1039/c8nr09836k.
GeSe is considered as a potential absorber material for thin film solar cells owing to its ideal band gap, strong light absorption, remarkable air durability, Earth-abundance and non-toxic constituents. However, the high vapor pressure of GeSe at a temperature below its melting point makes it difficult to synthesize a high-quality GeSe film. To alleviate this limitation, in this work, a thermal evaporation combining a novel sandwiching post-annealing method was introduced to deposit high quality GeSe thin films with (100)-orientation. The self-assembling mechanism of the highly oriented GeSe film was carefully investigated by the systematic experiments and confirmed by the lowest total energy of the (100) crystal plane. Finally, the fully-inorganic, low-cost and non-toxic planar device with the superstrate configuration of FTO/TiO2/GeSe/carbon/Ag was also successfully fabricated. Notably, as a result, an impressive open circuit voltage (VOC) of 340 mV (maximum: 456 mV) was achieved, which is the highest VOC of GeSe solar cells reported so far. Furthermore, through current-voltage, capacitance-voltage profiling and drive level capacitance profiling measurements, it was demonstrated that the limiting factors of the GeSe solar cell performance were the narrow depletion width (138 nm) and the drastic recombination at the TiO2/GeSe interface.
硒化锗因其理想的能带隙、较强的光吸收、显著的空气稳定性、丰富的地球储量和无毒成分而被认为是薄膜太阳能电池的潜在吸收材料。然而，硒化锗在其熔点以下的高蒸气压使得很难合成高质量的 GeSe 薄膜。为了缓解这一限制，在这项工作中，采用了一种热蒸发结合新颖的夹心后退火方法，沉积了具有（100）取向的高质量 GeSe 薄膜。通过系统的实验仔细研究了高度取向 GeSe 薄膜的自组装机制，并通过（100）晶面的最低总能量得到证实。最后，还成功制备了具有 FTO/TiO2/GeSe/碳/Ag 上覆结构的全无机、低成本和无毒平面器件。值得注意的是，作为结果，实现了 340 mV 的令人印象深刻的开路电压（VOC）（最大值：456 mV），这是迄今为止报道的 GeSe 太阳能电池的最高 VOC。此外，通过电流-电压、电容-电压轮廓和驱动电平电容轮廓测量，证明了 GeSe 太阳能电池性能的限制因素是窄耗尽宽度（138nm）和 TiO2/GeSe 界面处的剧烈复合。
