Atallah T L, Wang J, Bosch M, Seo D, Burke R A, Moneer O, Zhu Justin, Theibault M, Brus L E, Hone J, Zhu X-Y
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Department of Mechanical Engineering, Columbia University , New York, New York 10027, United States.
J Phys Chem Lett. 2017 May 18;8(10):2148-2152. doi: 10.1021/acs.jpclett.7b00710. Epub 2017 Apr 28.
Defects in monolayer transition-metal dichalcogenides (TMDCs) may lead to unintentional doping, charge-carrier trapping, and nonradiative recombination. These effects impair electronic and optoelectronic technologies. Here we show that charged defects in MoS monolayers can be effectively screened when they are in contact with an ionic liquid (IL), leading to an increase in photoluminescence (PL) yield by up to two orders of magnitude. The extent of this PL enhancement by the IL correlates with the brightness of each pretreated sample. We propose the existence of two classes of nonradiative recombination centers in monolayer MoS: (i) charged defects that relate to unintentional doping and may be electrostatically screened by ILs and (ii) neutral defects that remain unaffected by the presence of ILs.
单层过渡金属二硫属化物（TMDCs）中的缺陷可能导致意外掺杂、电荷载流子捕获和非辐射复合。这些效应会损害电子和光电子技术。在此我们表明，当MoS单层与离子液体（IL）接触时，其中的带电缺陷能够得到有效屏蔽，从而使光致发光（PL）产率提高多达两个数量级。IL对这种PL增强的程度与每个预处理样品的亮度相关。我们提出在单层MoS中存在两类非辐射复合中心：（i）与意外掺杂相关且可能被IL静电屏蔽的带电缺陷，以及（ii）不受IL存在影响的中性缺陷。
