Tao Ye, Koh See Wee, Yu Xuechao, Wang Chongwu, Liang Houkun, Zhang Ying, Li Hong, Wang Qi Jie
Centre for OptoElectronics and Biophotonics, School of Electrical and Electronic Engineering, The Photonics Institute, Nanyang Technological University 50 Nanyang Avenue 639798 Singapore.
School of Mechanical and Aerospace Engineering, Nanyang Technological University 50 Nanyang Avenue 639798 Singapore.
Nanoscale Adv. 2019 Oct 16;1(12):4783-4789. doi: 10.1039/c9na00395a. eCollection 2019 Dec 3.
Exciton/trion-involved optoelectronic properties have attracted exponential amount of attention for various applications ranging from optoelectronics, valleytronics to electronics. Herein, we report a new chemical (MXene) doping strategy to modulate the negative trion and neutral exciton for achieving high photoluminescence yield of atomically thin transition metal dichalcogenides, enabled by the regulation of carrier densities to promote electron-bound trion-to-exciton transition charge transfer from TMDCs to MXene. As a proof of concept, the MXene nano-flake-doped tungsten disulfide is demonstrated to obtain an enhanced PL efficiency of up to ∼five folds, which obviously exceeds the reported efficiency upon electrical and/or plasma doping strategies. The PL enhancement degree can also be modulated by tuning the corresponding surface functional groups of MXene nano-flakes, reflecting that the electron-withdrawing functional groups play a vital role in this charge transfer process. These findings offer promising clues to control the optoelectronic properties of TMDCs and expand the scope of the application of MXene nano-flakes, suggesting a possibility to construct a new heterostructure junction based on MXenes and TMDCs.
激子/三重子相关的光电特性在从光电子学、谷电子学到电子学等各种应用中引起了极大的关注。在此，我们报告了一种新的化学（MXene）掺杂策略，通过调节载流子密度以促进电子束缚三重子到激子的跃迁，实现从过渡金属二硫属化物到MXene的电荷转移，从而调制负三重子和中性激子，以实现原子级薄的过渡金属二硫属化物的高光致发光产率。作为概念验证，掺MXene纳米片的二硫化钨被证明可获得高达约五倍的增强光致发光效率，这明显超过了报道的电掺杂和/或等离子体掺杂策略的效率。光致发光增强程度也可以通过调节MXene纳米片的相应表面官能团来调控，这表明吸电子官能团在该电荷转移过程中起着至关重要的作用。这些发现为控制过渡金属二硫属化物的光电特性以及扩展MXene纳米片的应用范围提供了有前景的线索，暗示了构建基于MXene和过渡金属二硫属化物的新型异质结构结的可能性。
