Photoluminescence from Bi5(GaCl4)3 molecular crystal

TL;DR

This study synthesizes Bi5(GaCl4)3, analyzes its photoluminescent properties, and attributes its broadband emission to Bi53+ ions, providing insights for developing tunable laser materials.

Contribution

It is the first detailed analysis of Bi5(GaCl4)3's photoluminescence, identifying Bi53+ as the main emitter and linking electronic transitions to its broadband emission.

Findings

Bi5(GaCl4)3 exhibits ultrabroad emission from 1 to 2.7 micrometers.

Bi53+ ions are the dominant luminescent centers in the material.

Quantum calculations support the assignment of electronic transitions to Bi53+.

Abstract

Bi5(GaCl4)3 sample has been synthesized through the oxidation of Bi metal by gallium chloride (GaCl3) salt. Powder X-ray diffraction as well as micro-Raman scattering results revealed that, in addition to crystalline Bi5(GaCl4)3 in the product, amorphous phase containing [GaCl4]- and [Ga2Cl7]- units also exist. The thorough comparison of steady-state and time-resolved photoluminescent behaviors between Bi5(GaCl4)3 product and Bi5(AlCl4)3 crystal leads us to conclude that Bi53+ is the dominant emitter in the product, which gives rise to the ultrabroad emission ranging from 1 to 2.7 micrometer. Detailed quantum chemistry calculation helps us assign the observed excitations to some electronic transitions of Bi53+ polycation, especially at shorter wavelengths. It is believed that our work shown here not only is helpful to solve the confusions on the luminescent origin of bismuth in other material systems, but also serves to develop novel broadband tunable laser materials.