光致发光
量子点
石墨烯
量子产额
材料科学
光化学
拉曼光谱
拉曼散射
激发态
兴奋剂
分析化学(期刊)
化学
纳米技术
光电子学
荧光
原子物理学
物理
光学
有机化学
作者
Ruma Das,Sumaiya Parveen,Abhilasha Bora,P. K. Giri
出处
期刊:Carbon
[Elsevier]
日期:2020-04-01
卷期号:160: 273-286
被引量:87
标识
DOI:10.1016/j.carbon.2020.01.030
摘要
Herein, we elucidate the origin of high photoluminescence quantum yield (PL QY) and high surface-enhanced Raman scattering (SERS) sensitivity of in-situ nitrogen-doped graphene quantum dots (N-GQDs). We show that the doping of heteroatoms in GQDs facilitates the excited-state charge transfer and improved recombination in N-GQDs yielding a PL QY of ∼34%. Our study reveals that growth of GQDs in dimethyformamide solvent enables the reduction of the nonradiative sites in N-GQDs and the rearrangement of the charge distribution in the graphitic plane. Further, we demonstrate N-GQDs as an efficient SERS substrate with an enhancement factor of 3.2 × 103 with 10−4 M RhB target, which is ∼7-fold higher than the previous reports. The comparative studies of the SERS for undoped and N- and S-doped GQDs allow us to assess the contribution of the Förster resonance energy transfer (FRET) and chemical enhancement (CM) factors. Further, by controlling the functional groups of N-GQDs with vacuum annealing, and with different laser excitations, we isolate the contributions of CM and FRET, for the first time. The optimized N-GQDs exhibits a SERS detection limit of 10−10 M for RhB. Finally, N-GQDs combined with RhB is utilized to demonstrate a white light emitter with a CIE coordinate (0.30, 0.34).
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