Near-infrared photoluminescence from molecular crystals containing tellurium

TL;DR

This study discovers near-infrared photoluminescence from tellurium-containing molecular crystals, revealing Te42+ polycations as efficient emitters and exploring their potential for novel optical materials.

Contribution

It provides the first detailed analysis of Te42+ polycations as near-infrared emitters in molecular crystals, expanding the understanding of Te-related photophysical properties.

Findings

Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 emit at 1252 and 1258 nm

Emission depends on excitation wavelength due to other Te centers

Te42+ polycations are identified as intrinsic near-infrared emitters

Abstract

We report the observation of near-infrared photoluminescence from Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 molecular crystals containing Te42+ polycations. The experimental and theoretical results clearly revealed that Te42+ polycation is one smart near-infrared emitter with characteristic emission peaks at 1252 and 1258 nm for Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 crystals, respectively, resulting from the intrinsic electronic transitions of Te42+. Furthermore, it was also found that the emissions strongly depend on the excitation wavelengths for both Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 samples, most possibly owing to the co-existence of other Te-related optically active centers. This research not only enriches the species of luminescent charged p-block element polyhedra and deepens the understanding of Te-related photophysical behaviors, but also may stimulate efforts for designing novel material systems using such active centers. It is also greatly expected that these sub-nanometer optically active species could exist in other systems such as glasses, polymers, and bulk optical crystals, and the stabilization of these centers in widely used hosts will pave the way for their practical applications.