Spectral Regulation in Cs<sub>2</sub>PtCl<sub>6</sub> Double Perovskite via Low-Temperature and High-Pressure Engineering for Advanced Optical Thermometry and Manometry
Zhiyu Pei, Marcin Runowski, Xuanyu Ge, Przemysław Woźny, Laihui Luo, Peng Du
Abstract
To build a bifunctional luminescent platform for optical thermometry and manometry, the Cs 2 PtCl 6 double perovskite was synthesized. Upon 468 nm excitation, the designed compound emitted bright red light centered at ≈675 nm, originating from the 3 T 1g, 3 T 2g → 1 A 1g transition of Pt 4+, whose fluorescence intensity and bandwidth are highly temperature dependent. Moreover, the temperature-dependent decay curves of the developed Cs 2 PtCl 6 double perovskite were measured to explore its application in optical thermometry, of which its maximum relative sensor sensitivity is 1.21% K –1, with the operation range of 100–310 K. Furthermore, the impact of pressure on the phase structure and luminescence behaviors of the Cs 2 PtCl 6 double perovskite was also discussed. The pressure-dependent Raman spectra clarified that the synthesized compound possesses a stable phase structure at high pressure. Furthermore, Cs 2 PtCl 6 double perovskite exhibits distinct spectral blue-shift at high pressure. Importantly, as pressure increases (i.e., 0–5.67 GPa), the emission band centroid and full width at half-maximum (fwhm) are both linearly dependent on pressure, resulting in high pressure sensitivities of dλ/d p = 7.19 nm/GPa and d fwhm /d p = 4.95 nm/GPa, respectively. Our finding manifests that the luminescence characteristics of the Cs 2 PtCl 6 double perovskite can be efficiently regulated via low temperature and high pressure, enabling its applications in optical thermometry and manometry.