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arXiv · 2501.05705

Structural transition and emission enhancement in vacancy ordered halide double perovskite Cs$_2$TeCl$_6$ under pressure

Suvashree Mukherjee·Debabrata Samanta·Bidisha Mukherjee·Konstantin Glazyrin·Goutam Dev Mukherjee
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Abstract

The effect of pressure on the structural evolution, enhancement of photoluminescence intensity and optical band gap of a vacancy ordered double halide perovskite Cs$_2$TeCl$_6$ is investigated systematically. We use synchrotron x-ray diffraction, Raman spectroscopy, optical band gap and photoluminescence measurements to explore the structural and the optical properties of Cs$_2$TeCl$_6$ under pressure up to 30.0 GPa. We find that Cs$_2$TeCl$_6$ undergoes a structural transition from cubic Fm$\bar{3}$m to monoclinic P2$_1$/n at very low pressure below 1.0 GPa. A significant increase in photoluminescence intensity and a rapid decrease in optical band gap are observed, which are related to the octahedral distortion and structural transition. Interestingly, with increasing pressure, the sample regains its ambient Fm$\bar{3}$m structure at around 3.4 GPa maintaining the cubic phase up to 30.0 GPa. The sample undergoes an iso-structural transition at around 14.1 GPa pressure with a slight decrease in compressibility.

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Suvashree Mukherjee, Debabrata Samanta, Bidisha Mukherjee, Konstantin Glazyrin, Goutam Dev Mukherjee. 2025-01-10. Structural transition and emission enhancement in vacancy ordered halide double perovskite Cs$_2$TeCl$_6$ under pressure. https://arxiv.org/abs/2501.05705

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