Polarization-sensitive visible emission of ordered CdSe/CdS nanorod films

Abstract

The polarization-sensitive optical properties of semiconductor nanorods (NRs) are attractive characteristics for optical devices. Although oriented NR films can provide convenient integration and new application opportunities, the realization of large-area NR films with polarized photoluminescence (PL) remains a challenge. Herein, we fabricated ordered CdSe/CdS NR films on an arbitrary substrate using the Langmuir-Blodgett technology. Polarization-sensitive PL was observed for the NR films. The band-edge exciton fine structure owing to the rod-like morphology and the dielectric effect of the orderly arranged NRs were discussed with a focus on the contribution to polarized photons. The degree of linear polarization of the CdSe/CdS NR films excited a circularly polarized light was approximately 0.30. When linearly polarized ultraviolet (UV) light was used as the excitation source, the PL intensity of the NR films periodically varied with the polarization direction of the UV light. The corresponding PL polarization (i.e., “excitation polarization”) was approximately 0.28. The polarization-sensitive fluorescence (approximately 526 nm) excited by the UV-polarized light (325 nm) demonstrates the potential for realizing low-cost polarization-sensitive devices using only a visible light charge-coupled device system.