Zhu Haixia, Chen Zhaozhe, Dai Rui, Yang Bojun, Zhong Mianzeng, Xiao Si, He Jun
Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China.
Nanoscale. 2024 Jun 20;16(24):11716-11723. doi: 10.1039/d4nr01518e.
Alloy engineering plays an important role in regulating the optoelectronic properties of materials. This work demonstrates that BiTeS alloys can extend nonlinear optical response to the near-infrared range. Te alloying at S sites can narrow the band gap, as proved by density functional theory (DFT) calculations, leading to a broadband saturable absorption response ranging from ultraviolet (350 nm) to near-infrared (1100 nm) wavelength with negative nonlinear optical absorption coefficient ranging from -0.12 cm GW to -1.28 cm GW. Moreover, the broadband carrier dynamic of BiTeS alloys was investigated femtosecond transient absorption (TA) at an excitation of 325 nm. A faster carrier dynamic at near-infrared wavelength was observed because of an increase in electron density at the conduction band minimum due to the additional Bi-Te interaction, which was corroborated by DFT calculations. These results suggest that alloy engineering provides an effective way for the development of broadband nonlinear optical devices.
合金工程在调节材料的光电性能方面起着重要作用。这项工作表明，BiTeS合金可以将非线性光学响应扩展到近红外范围。正如密度泛函理论（DFT）计算所证明的那样，在S位点进行Te合金化可以缩小带隙，从而导致从紫外（350 nm）到近红外（1100 nm）波长的宽带饱和吸收响应，其负非线性光学吸收系数范围为-0.12 cm GW至-1.28 cm GW。此外，利用飞秒瞬态吸收（TA）技术在325 nm激发下研究了BiTeS合金的宽带载流子动力学。由于额外的Bi-Te相互作用导致导带最小值处电子密度增加，在近红外波长处观察到了更快的载流子动力学，这得到了DFT计算的证实。这些结果表明，合金工程为宽带非线性光学器件的开发提供了一种有效方法。
