Phosphorescent Microcrystals Assembled by Geometrically Isomeric Chiral Organoplatinum(II) Compounds for Polarization-Programmable Anticounterfeiting

Abstract

Polarized luminescent materials have emerged as a class of photofunctional materials with great significance and enormous potential in applications such as three-dimensional (3D) displays and information encryption. However, the polarized luminescence properties and their practical applications have not received sufficient attention in the materials community. Herein, we synthesized a series of geometric-isomeric, chiral organoplatinum(II) compounds and investigated the polarized luminescence properties of their luminescent microcrystals. The chiral organoplatinum(II) compound microcrystals, with regular rod morphology, are efficiently prepared and display distinct linearly and elliptically polarized luminescence characteristics, with one polarization degree as high as 0.74. Furthermore, the microcrystals show circularly polarized luminescent properties with a long lifetime of 1.5 μs, which is typical of chiral phosphorescence characteristics. Nevertheless, the layered and centrosymmetric arrangement of the compounds in the microcrystals affects and reduces the overall luminescent chirality of the material, giving rise to a small asymmetry factor (g) of 10–4. All-polarization 3D anticounterfeiting, based on the luminescent organoplatinum(II) microcrystal arrays, is also demonstrated. These results establish geometric-isomeric Pt(II) complexes as a versatile micro/nanophotonic platform for polarization-enabled devices beyond conventional circularly polarized luminescent materials.