Local crystal field-induced tunable mid-infrared luminescence of CsPb_1-xEr_xBr₃ perovskite fluoride glasses and applied to the detection of CO₂ in hydrogen energy

In recent years, the mid-infrared (MIR) source has become important for a wide range of applications in sensing, spectroscopy, imaging and communications. Due to the unique intra-4f shell transition, the infrared luminescence of rare earth ions has been widely used in infrared light-emitting devices. Despite recent advances with mid-infrared gain platforms, the lack of a tunable mid-infrared luminescence mechanism remains a significant technological challenge. Here, an efficient mechanism for tuning the local crystal field of rare earth ions by modifying the crystal structure of rare earth perovskites is revealed and tunable mid-infrared luminescence of rare earth ions is achieved. Significantly, the local crystal field of Er3+ is tuned by changing the crystal structure of the CsPb1-xErxBr3 rare earth perovskite. The energy level transition (1550 nm: 4I13/2 & RARR; 4I15/2 and 2.7 & mu;m: 4I11/ 2 & RARR; 4I13/2) is changed by tuning the asymmetry of the crystal field and the FWHM of the mid-infrared emission is tunable from 80 nm to 130 nm. A convenient, highly accurate device has also been developed that can be used to measure the CO2 concentration in hydrogen energy. The perovskite glass infrared light source has been well adapted to the characteristic infrared absorption peak of CO2. The instrument can monitor the CO2 concentration in real time, avoiding the safety risks associated with the use of electronic instruments in hydrogen energy. These results are expected to open a wide avenue for a new type of tunable mid-infrared luminescence for a wide range of applications.