具摻雜之二硫化鎢量子點之光學特性

Optical properties of tungsten disulfide quantum dots with doping

張雨喬(Yu-Qiao Zhang)

指導教授 ： 沈志霖

中原大學/理學院/物理研究所/碩士(2020年)

https://doi.org/10.6840/cycu202000934

摘要

本研究利用微波合成法製造二硫化鎢量子點。在微波合成法的過程中加入摻雜物，成功合成出乙二胺/二硫化鎢量子點、半胱胺/二硫化鎢量子點、乙二硫醇/二硫化鎢量子點。藉由透過穿透式電子顯微鏡來證明我們所合成的量子點約4.5 nm，由此證明微波合成法合成出二硫化鎢量子點是成功的。利用X射線光電子能譜確認摻雜的化合物在二硫化鎢量子點結構中。並且藉由比較三種摻雜物的光激螢光，發現乙二胺/二硫化鎢量子點會隨著摻雜乙二胺的濃度增加而增加，光激螢光最高增加125倍加，這是因為鈍化作用產生的。巰基和二硫化鎢量子點的光激螢光強度隨著摻雜濃度增加而變低，可能和缺陷有關連，缺陷越多，電子電洞越不易複合放光。我們發現乙二胺/二硫化鎢量子點的光激螢光激發光譜、吸收光譜中，隨著量子點濃度增加，激子訊號有紅位移現象，並且在時間解析光激螢光譜發現其載子生命期縮短，這是因為激子J聚集的影響。藉由拉曼光譜的量測二硫化鎢摻雜的樣品中A1g/E12g的強度隨著摻雜濃度增加而減弱，這可由電子-聲子耦和效應解釋。

關鍵字

二硫化鎢 ； 量子點 ； 微波合成法 ； 光激螢光光譜 ； 吸收光譜

並列摘要

In this study, microwave synthesis was used to manufacture tungsten disulfide quantum dots. Adding a dopant during the microwave synthesis method successfully synthesized ethylenediamine / tungsten disulfide quantum dots, cysteamine / tungsten disulfide quantum dots, and ethylenedithiol / tungsten disulfide quantum dots. The TEM(transmission electron microscope) was used to prove that the quantum dots we synthesized were about 4.5 nm, which proved that the synthesis of tungsten disulfide quantum dots by microwave synthesis was successful. The characteristic measurement by useing XPS(X-ray photoelectron spectroscopy). And by comparing the PL of the three dopants, it was found that the ethylenediamine / tungsten disulfide quantum dots would increase with increase concentration of doped ethylenediamine, and the PL intensity light up to 125 times. This is because caused by passivation. The light-induced fluorescence intensity of thiol and tungsten disulfide quantum dots decreases with the increase of the doping concentration, and may be related to defects. The more defects, the more difficult it is for electron holes to recombine. We find PLE spectra of ethylenediamine / tungsten disulfide quantum dots, as the quantum dot concentration increases, the exciton signal has a red shift phenomenon, and its carriers are found in time-resolved light-excitation fluorescence spectra. The lifetime is shortened due to the effect of exciton J aggregation. The intensity of A1g / E12g in tungsten disulfide-doped samples was measured by Raman spectroscopy, and the intensity decreased with increasing doping concentration, which can be explained by the electron-phonon coupling effect.

並列關鍵字

WS2 ； Quantum dots ； Microwave ； Photoluminescence ； Absorption

參考文獻

1. X.-M. Chen, G.-H. Wu, Y.-Q. Jiang, Y.-R. Wang and X. Chen. Analyst, 136, 4631-4640 (2011).

2. Nyangiwe, N.N. (2012). Graphene based nano-coatings: synthesis and physical-chemical investigations.

3. K. S. Novoselove, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva and A. A. Firsov, Science, 306, 5696 (2004)

4. Xuesong Li, Weiwei Cai,Jinho An,Seyoung Kim,Junghyo Nah, Dongxing Yang,Richard Piner, Aruna Velamakanni, Inhwa Jung, Emanuel Tutuc, Sanjay K. Banerjee, Luigi Colombo, Rodney S. Ruoff, Science 324, 1312 (2009).

5. B. Radisavljevic, A. Radenovic, J. Brivio, V. Giacometti & A. Kis, Nat Nanotechnol 6, 147 (2011)