Removing Defects in WSe2 via Surface Oxidation and Etching to Improve Solar Conversion Performance,ACS Energy Letters

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Removing Defects in WSe2 via Surface Oxidation and Etching to Improve Solar Conversion Performance
ACS Energy Letters ( IF 19.3 ) Pub Date : 2018-12-03 00:00:00 , DOI: 10.1021/acsenergylett.8b01922
Melinda J. Shearer ₁ , Wenjie Li ₁ , Jayson G. Foster _{1,

2} , Matthew J. Stolt ₁ , Robert J. Hamers ₁ , Song Jin ₁

Affiliation

Layered metal dichalcogenide materials (MX₂) have great potential for solar energy conversion. However, as-grown MX₂ materials often contain edge and terrace defects that degrade semiconducting properties and hinder their solar performance. Herein, we demonstrate a simple approach to removing surface defects and improving the solar performance by using UV-generated ozone to oxidize the surface of WSe₂ nanoplates and single crystals, followed by a simple soak in aqueous solutions to remove the oxide. Structural characterizations reveal that defective edges and basal plane defect sites are selectively oxidized and subsequently etched, and the ratio of the nonstoichiometric WSe_x species is reduced. After this treatment, p-type WSe₂ single crystals show increased electron accumulation on the surface and significantly enhanced photoelectrochemical solar conversion efficiency. These results and insights will be useful in the improvement and utilization of layered MX₂ materials based on both Se and S for solar energy conversion and other device applications.

中文翻译：

通过表面氧化和蚀刻去除WSe _2中的缺陷，以提高太阳能转换性能

层状金属二硫化氢材料（MX ₂）具有巨大的太阳能转化潜力。但是，已生长的MX ₂材料通常包含边缘和平台缺陷，这些缺陷会降低半导体性能并阻碍其太阳能性能。在这里，我们演示了一种简单的方法来消除表面缺陷，并通过使用紫外线产生的臭氧氧化WSe ₂纳米板和单晶的表面，然后在水溶液中进行简单的浸泡来去除氧化物，从而改善太阳能性能。结构表征表明，缺陷边缘和基面缺陷部位被选择性地氧化并随后被蚀刻，并且非化学计量的WSe _x物种的比率降低。经过此处理后，p型WSe₂个单晶显示出增加的电子在表面上的积累，并显着提高了光电化学太阳转化效率。这些结果和见解将有助于改进和利用基于Se和S的多层MX ₂材料，用于太阳能转换和其他设备应用。

更新日期：2018-12-03

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