Influence of surface charges on the emission polarization properties of single CdSe/CdS dot-in-rods

• Published in: Frontiers of physics Vol. 14; no. 6; p. 63601
• Main Authors: Zhang, Guo-Feng, Yang, Chang-Gang, Ge, Yong, Peng, Yong-Gang, Chen, Rui-Yun, Qin, Cheng-Bing, Gao, Yan, Zhang, Lei, Zhong, Hai-Zheng, Zheng, Yu-Jun, Xiao, Lian-Tuan, Jia, Suo-Tang
• Format: Journal Article
• Language: English
• Published: Beijing Higher Education Press 01.12.2019; Springer Nature B.V
• Subjects: Astronomy; Astrophysics and Cosmology; Atomic; band-edge exciton fine structure; Blinking; Cadmium selenides; Cadmium sulfide; Condensed Matter Physics; Electron transfer; Electrons; Emission analysis; Emissions; Excitons; Fine structure; Indium tin oxides; Influence; Mathematical analysis; Molecular; N-type semiconductors; Optical and Plasma Physics; Particle and Nuclear Physics; Photoluminescence; Physics; Physics and Astronomy; Polarization; polarization properties; Research Article; Rods; single CdSe/CdS dot-in-rods; surface charges; single CdSe/CdS dot-in-rods; surface charges; band-edge exciton fine structure; polarization properties
• ISSN: 2095-0462; 2095-0470
• DOI: 10.1007/s11467-019-0916-1

We report an experimental investigation of the influence of surface charges on the emission polarization properties of single CdSe/CdS dot-in-rods (DRs), which is important for their polarization-based practical applications. By covering the single DRs with N-type semiconductor indium tin oxide (ITO) nanoparticles, the surface of single DRs is charged by ITO through interfacial electron transfer. This is confirmed by the experimental observations of the reduced photoluminescence intensities and lifetimes as well as the suppressing blinking. It is found that the full width at half maximum of histogram of polarization degrees of the single DRs is broadened from 0.24 (on glass) to 0.41 (in ITO). In order to explain the exprimental results, the band-edge exciton fine structure of single DRs is calculated by taking into account the sample parameters, the emission polarization, and the surface charges. The calculation results show that the level ordering of the emitting states determines the polarization degrees tending to increase or decrease under the influence of surface electrons. The surface electrons can induce an increase in the spacing between the emitting levels to change the populations and thus change the polarization degrees. In addition, different numbers of surface electrons may randomly distribute on the long CdSe/CdS rods, leading to the heterogeneous influences on the single DRs causing the broadening of polarization degrees also.