石墨烯杂化物光致发光的猝灭

5^th理论、材料和凝聚态物理国际会议

2018年11月26日至28日|美国洛杉矶

Mahi R Singh

加拿大西安大略大学

海报和接受的摘要:Res. Rev. J Mat. science

DOI:10.4172 / 2321 - 6212 c10 - 042

摘要

石墨烯杂化体的等离子体性质是近年来研究的热点。石墨烯是华莱士在1947年从理论上发明的。他预测石墨烯是一种无间隙NS，具有间接带隙。后来Wallace和我又发现了更多的无隙材料，如Cd3AS2, HgTe，这些材料都有直接带隙。结果表明，直接带隙材料的光能吸收/发射比间接带隙材料强。最近，石墨烯类纳米结构如锗烯和硅烷被发明出来。在这里，我们研究了沉积在介电材料如Si上的量子点(QD)-金属纳米颗粒和金属石墨烯薄膜(QD- mn - g)杂化体系的光致发光猝灭。在准静态近似下求解石墨烯和介电异质结构的麦克斯韦方程组，计算了表面等离子激元极化元。量子点具有激子，激子与石墨烯-介电异质结构的SPPs相互作用。利用量子密度矩阵方法，研究了激子- spp耦合作用下量子点的光致发光现象。 Numerical simulations for the PL spectrum in the QD is performed for (QD-MN-G) hybrid system. It is found that when the exciton energy of the QD is in resonant with the SPP energy the intensity of the photoluminescence is quenched. The PL quenching occurs is due to the transfer of photon energy from the QD to the graphene film and MNP due to the exciton-SPP coupling. Furthermore, when the exciton energy is non-resonant with the SPP energy the PL quenching disappears. The energy transfer from the QDs to the graphene film can be switched ON and OFF by mismatching the resonant energies of excitons and polaritons. The mismatching of energies can be achieved by applying external pump lasers or stress and strain fields. Recently Dong et al. and Zeng et al. have measured the PL spectrum of QDs in QD-G hybrid and QD-MN-G hybrid, respectively. In both experiments, they have observed the PL quenching. We have compared our theory with these experiments and found a good agreement between theory and experiments. These are interesting findings and they can be used to fabricate switches and sensors by using graphene nanocomposites.

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