Chiral structures draw much attention due to their relationship to the polarized light, chiral sensing, and biological structures. Circularly polarized emission (CPE) of chiral materials promotes the development of smart photonic materials for advanced applications in biological systems and information storage. For the CPE, it has been frequently observed in single molecules. Molecular assemblies possess higher levels of CPE performance in comparison with organic single molecules, because the single molecular sizes are much smaller than the helical pitch of circularly polarized light.
Recently, Prof. Qin Wei et al. have fabricated chiral helical polymeric nanowires to study the orbital angular momentum dependent circularly polarized emission. The results are published in the Advanced Materials with the title of "Magnetic and Electric Control of Circularly Polarized Emission through Tuning Chirality-Generated Orbital Angular Momentum in Organic Helical Polymeric Nanofbers". The first author of the paper is Dr. Wang Zhongxuan, and the corresponding author is Prof. Qin Wei.
Taking into account the chirality induced orbital angular momentum, spin relaxation time in chiral nw-P3HTs decreases to the level of tens of picosecond, which is comparable to the charge recombination time to lead to an observation of circularly polarized emission. Both the external magnetic fields and electric field are applied to tune the splitting of energy levels to further change the effect of circularly polarized emission.
In the past two years, the research of organic chiral crystals and magneto-optic effects of co-crystals have been carried out by Qin's group. The related works have been published in Adv. Mater., ACS Nano, Adv. Opt. Mater., APL. The results are supported by the NSFC, Taishan Scholar of Shandong Province, and the Fundamental Funds of Shandong University.
Source: the School of Physics
Written by: Qin Wei
Edited by: Xie Tingting