Tunable Light Polarization Information from Single Upconverting Fluoride Microcrystal

• Published in: Advanced optical materials 2021-07, Vol.9 (13), p.n/a
• Main Authors: Yang, Dandan, Peng, Zixing, Guo, Xin, Qiao, Shuqian, Zhao, Pu, Zhan, Qiuqiang, Qiu, Jianrong, Yang, Zhongmin, Dong, Guoping
• Format: Article
• Language: English
• Subjects: anisotropic structure; Anisotropy; Crystal structure; Density functional theory; Dipoles; Doping; Electric fields; Electron clouds; Energy transfer; excitation polarization; light polarization characteristic; Materials science; Microcrystals; Nanomaterials; optical storage; Optics; Optoelectronics; Photoelectricity; Polarization characteristics; Polarized light; rare‐earth ions; upconversion
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202100044

The key components in display, imaging, data communication, and photoelectric detection fields are low‐dimensional micro‐/nanomaterials with highly anisotropic optoelectronic properties manifesting polarized light. However, for anisotropic upconversion (UC) materials, obtaining tunable polarization characteristics remains a significant challenge. Herein, based on a detailed investigation of the crystal structure, local symmetry, and properties of rare‐earth ions (RE3+), the authors successfully realized a tunable UC light polarization characteristic (UCLPC) with dependence on excitation polarization using a series of RE3+ single‐ or co‐doped β‐NaYF4 microrods. By simulating the electron cloud distribution and bonding structure based on density functional theory calculations, it is shown that: i) Yb3+ with a unique electron cloud distribution adjusts the UCLPC of the activator via energy transfer processes; ii) co‐doping with RE3+ having a larger dipole polarizability improves the UCLPC of the activator by performing its electric field distribution toward anisotropy; and iii) increasing the activator concentration strengthens the UCLPC. By exploiting the unique UCLPC from different doping combinations, applications in optical storage, encryption, and anti‐counterfeiting are illustrated. Simultaneously, the findings obtained in this work will provide new and exciting fundamental insights into understanding the polarization properties of RE3+ in an anisotropic structure. Based on detailed analysis and calculations, it is revealed that, except for crystal and coordination structure, the upconversion light polarization characteristic (UCLPC) of rare‐earth ions (RE3+) is related to the properties of RE3+, energy transfer processes, and adjacent ions. Accordingly, three general approaches are highlighted to realize a tunable UCLPC. Exploiting the unique UCLPC, applications in optical storage and anti‐counterfeiting are illustrated.