Soni Ashish, Kushavah Dushyant, Lu Li-Syuan, Chang Wen-Hao, Pal Suman Kalyan
School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Mandi 175005, Himachal Pradesh, India.
Advanced Materials Research Centre, Indian Institute of Technology Mandi, Kamand, Mandi 175005, Himachal Pradesh, India.
J Phys Chem Lett. 2023 Mar 30;14(12):2965-2972. doi: 10.1021/acs.jpclett.3c00306. Epub 2023 Mar 20.
Utilization of the excess energy of photoexcitation that is otherwise lost as thermal effects can improve the efficiency of next-generation light-harvesting devices. Multiple exciton generation (MEG) in semiconducting materials yields two or more excitons by absorbing a single high-energy photon, which can break the Shockley-Queisser limit for the conversion efficiency of photovoltaic devices. Recently, monolayer transition metal dichalcogenides (TMDs) have emerged as promising light-harvesting materials because of their high absorption coefficient. Here, we report efficient MEGs with low threshold energy and high (86%) efficiency in a van der Waals (vdW) layered material, MoS. Through different experimental approaches, we demonstrate the signature of exciton multiplication and discuss the possible origin of decisive MEG in monolayer MoS. Our results reveal that vdW-layered materials could be a potential candidate for developing mechanically flexible and highly efficient next-generation solar cells and photodetectors.
利用否则会以热效应形式损失的光激发过剩能量，可以提高下一代光收集装置的效率。半导体材料中的多激子产生（MEG）通过吸收单个高能光子产生两个或更多激子，这可以突破光伏器件转换效率的肖克利-奎塞尔极限。最近，单层过渡金属二硫属化物（TMD）因其高吸收系数而成为有前景的光收集材料。在此，我们报告了在范德华（vdW）层状材料MoS中具有低阈值能量和高（86%）效率的高效MEG。通过不同的实验方法，我们证明了激子倍增的特征，并讨论了单层MoS中决定性MEG的可能起源。我们的结果表明，vdW层状材料可能是开发机械柔性且高效的下一代太阳能电池和光电探测器的潜在候选材料。
