Burgués-Ceballos Ignasi, Wang Yongjie, Konstantatos Gerasimos
ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
ICREA-Institució Catalana de Recerca i Estudis Avancats, Passeig Lluís Companys 23, 08010 Barcelona, Spain.
Nanoscale. 2022 Mar 31;14(13):4987-4993. doi: 10.1039/d2nr00589a.
Heavy-metal-free colloidal nanocrystals are gaining due attention as low-cost, semiconducting materials for solution-processed optoelectronic applications. One common limitation of such materials is their limited carrier transport and trap-assisted recombination, which impede the performance of thick photoactive layers. Here we mix small-size and large-size AgBiS nanocrystals to judiciously favour the band alignment in photovoltaic and photodetector devices. The absorbing layer of these devices is fabricated in a gradient fashion in order to maximise charge transfer and transport. We implement this strategy to fabricate mixed AgBiS thin film solar cells with a power conversion of 7.3%, which significantly surpasses the performance of previously reported devices based on single-batch AgBiS nanocrystals. Additionally, this approach allows us to fabricate devices using thicker photoactive layers that show lower dark currents and external quantum efficiencies exceeding 40% over a broad bandwidth - covering the visible and near infrared range beyond 1 μm, thus unleashing the potential of colloidal AgBiS nanocrystals in photodetector applications.
无重金属胶体纳米晶体作为用于溶液处理光电器件的低成本半导体材料正受到越来越多的关注。这类材料的一个常见限制是其有限的载流子传输和陷阱辅助复合，这会阻碍厚光活性层的性能。在此，我们将小尺寸和大尺寸的AgBiS纳米晶体混合，以明智地优化光伏和光电探测器器件中的能带排列。这些器件的吸收层以梯度方式制造，以最大化电荷转移和传输。我们采用这种策略制造了混合AgBiS薄膜太阳能电池，其功率转换效率为7.3%，显著超过了先前报道的基于单批次AgBiS纳米晶体的器件性能。此外，这种方法使我们能够制造使用更厚光活性层的器件，这些器件显示出更低的暗电流，并且在覆盖可见光和超过1μm的近红外范围的宽光谱带宽上具有超过40%的外部量子效率，从而释放了胶体AgBiS纳米晶体在光电探测器应用中的潜力。
