Exceptional size-dependent property of TiS2 nanosheets for optical limiting
Exceptional size-dependent property of TiS2 nanosheets for optical limiting
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DOI：
10.1016/j.apsusc.2020.148371
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发表时间：
2021-03-01
影响因子：
6.7
通讯作者：
Peng, Xiangfang
中科院分区：
文献类型：
--
作者：
Liu, Yang;Li, Xian;Peng, Xiangfang
过渡金属二硫属化物（TMD）是一种新兴的光限幅材料，对高能激光具有优异的光限幅性能。一般来说，随着横向尺寸的减小，TMDS材料表现出更好的激光保护作用。然而，在这项工作中，TiS 2纳米片表现出特殊的横向尺寸依赖性的光限幅性能相反，所报道的TMD纳米片。得到了厚度相近、横向尺寸为50 nm、100 nm、150 nm、350 nm的TiS 2纳米片。大尺寸的TiS 2纳米片显示出更好的光限幅性能，并开发出具有超低归一化透射率（低至12%）的TiS 2纳米片。有趣的是，发现在带隙为2.67 eV的大TiS 2纳米片（350 nm）中表现出双光子吸收（TPA）和反饱和吸收（RSA），而在带隙为3.51 eV的小TiS 2纳米片（50 nm）中仅存在TPA。此外，掺入极低含量（0.066 wt%）的聚甲基丙烯酸甲酯（PMMA）样品的TiS 2纳米片表现出18%的低归一化透射率，沿着具有低的初始阈值（0.03 J/cm（2））和低的光学阈值（0.57 J/cm（2）），这显示了TiS 2纳米片在光限幅领域的实际应用的巨大潜力。
Transition metal dichalcogenides (TMDs), an emerging optical limiting material, exhibit excellent optical limiting properties for high energy laser. Generally, TMDs materials showed better laser protection with the decrease of lateral sizes. However, in this work, TiS2 nanosheets showed exceptional lateral size-dependent optical limiting property contrary to the reported TMDs nanosheets. TiS2 nanosheets with similar thickness and varied lateral sizes of 50 nm, 100 nm, 150 nm, 350 nm were obtained. Larger size TiS2 nanosheets displayed better optical limiting performance and TiS2 nanosheets with ultra-low normalized transmittance (as low as 12%) were developed. It was interesting to find that both two-photon absorption (TPA) and reverse saturable absorption (RSA) were exhibited in large TiS2 nanosheets (350 nm) with a bandgap of 2.67 eV, while in small TiS2 nanosheets (50 nm) with a bandgap of 3.51 eV, only TPA existed. Furthermore, the TiS2 nanosheets incorporated polymethyl methacrylate (PMMA) sample with an extremely low content of 0.066 wt%o TiS2 nanosheets exhibited a low normalized transmittance of 18%, along with a low initial threshold (0.03 J/cm(2)) and low optical threshold (0.57 J/cm(2)), which showed great potential for practical use of the TiS2 nanosheets in optical limiting field.