The preparation and up-conversion properties of full spectrum CsPbX₃ (X = Cl, Br, I) quantum dot glasses

All-inorganic perovskite (CsPbX3) quantum dots (QDs) have achieved unprecedented success in various applications due to their outstanding performance. Nevertheless, the inherent instability of these QDs severely limits their practical applications. Here, ultra-stable full visible spectrum CsPbX3 (X = Cl, Br, I) QD glasses are prepared successfully. For the first time, the full spectrum tunable up-conversion (UC) emission of CsPbX3 QD glasses ranging from 420 nm to 711 nm under excitation with an 800 nm femtosecond (fs) laser was achieved. Importantly, the two-photon absorption properties, the exciton binding energy and the UC full width at half maximum (FWHM) of CsPbCl1.5Br1.5 (blue), CsPbBr3 (green), and CsPbBr1.5I1.5 (red) QD glasses were studied in depth. Furthermore, CsPbCl1.5Br1.5 showed the highest exciton binding energy (∼87.5 meV), allowing the CsPbCl1.5Br1.5 QD glass to act as a good optical gain material that could more easily achieve amplified spontaneous emission (ASE).