Nat. Commun.: single photon emission research results of nanocrystalline clusters by Xiao Min and Wang Xiaoyong research groups of Nanjing University

Professor Xiao Min and Professor Wang Xiaoyong from the school of physics of Nanjing University made important progress in the research of single photon emission of nanocrystalline clusters, and the relevant results were recently published on nature communications (DOI: 10.1038/s41467-018-03971-w) In this work, we first synthesized large-scale core-shell CdSe / CdS nanocrystals By adjusting the passivation ligands on the outside of the nanocrystals and purifying them several times, using the minimization of surface free energy and the effect of dipole attraction, the group successfully realized the large-scale synthesis of nanocrystal clusters By using single particle spectroscopy, the high efficiency fluorescence emission of a single nanocrystal cluster was observed at room temperature, and each nanocrystal cluster has more than four times enhanced photon absorption cross section compared with a single independent nanocrystal The research team believes that under the coherent coupling between the nanocrystals in the cluster, the photogenerated excitons in one nanocrystal can transfer energy to the photogenerated excitons in the adjacent nanocrystals through the non fluorescence emission Auger recombination process, resulting in only one nanocrystal in the final cluster to retain the excitons and generate single photon emission after the transition to the ground state The synthesis of nanocrystalline clusters and their large absorption cross section not only achieve high efficiency single photon emission under low energy injection, but also provide a unique material platform for studying the evolution of photoelectric properties in the transition from single nanocrystalline to nanocrystalline molecules The first co authors of this paper are LV Bihu, a 2013 Ph.D student from the school of physics, Nanjing University, and Zhang Huichao, a postdoctoral student The first corresponding author is Professor Wang Xiaoyong, and the co authors are Professor Xiao Min and Professor zhangjiayu from Southeast University Corresponding author: Professor Wang Xiaoyong, Professor Xiao Min