# The Crystal Structure and Luminescence Behavior of Self-Activated Halotungstates Ba3WO5Cl2 for W-LEDs Applications

## TL;DR

This paper reports the synthesis and study of a new halotungstate material with luminescent properties useful for LED applications.

## Contribution

The novel contribution is the synthesis and detailed characterization of Ba3WO5Cl2, revealing its self-activated luminescence and thermal quenching behavior.

## Key findings

- Ba3WO5Cl2 has a monoclinic crystal structure confirmed by XRD.
- The material exhibits strong blue emission at 450 nm under UV excitation.
- Thermal quenching of luminescence was observed and modeled.

## Abstract

The self-activated halotungstate Ba3WO5Cl2 was successfully synthesized using a high-temperature solid-state method. X-ray diffraction analysis (XRD) confirmed the formation of a single-phase compound with a monoclinic crystal structure, ensuring the material’s purity and structural integrity. The luminescence properties of Ba3WO5Cl2 were thoroughly investigated using both optical and laser-excitation spectroscopy. The photoluminescent excitation (PLE) and emission (PL) spectra, together with the corresponding decay curves, were recorded across a broad temperature range, from 10 K to 480 K. The charge transfer band (CTB) of the [WO5Cl] octahedron was clearly identified in both the PL and the PLE spectra under ultraviolet light excitation, indicating efficient energy transfer within the material’s structure. A strong blue emission could be detected around 450 nm, which is characteristic of the material’s luminescent properties. However, this emission exhibited thermal quenching as the temperature increased, a common phenomenon where the luminescence intensity diminishes due to thermal effects. To better understand the thermal quenching behavior, variations in luminescence intensity and decay time were analyzed using a straightforward thermal quenching model. This comprehensive study of Ba3WO5Cl2 luminescent properties not only deepens the understanding of its photophysical behavior but also contributes to the development of novel materials with tailored optical properties for specific technological applications.