Improving near-infrared luminescence in Er3+ doped CsPbBr3 quantum dots glasses through a certain energy transfer process

Er 3+ has received extensive attention due to its excellent optical properties, especially its emission at 1535 nm in atmospheric propagation window. Enhancement and regulation of 1535 nm emission of Er 3+ is of great significance to optical communication. In this work, growing of CsPbBr 3 QDs has been controlled through adjusting annealing time which would precisely regulate conduction band of CsPbBr 3 QDs to match energy levels of Er 3+ enabling energy transfer between Er 3+ and CsPbBr 3 QDs. By steady-state and transient PL emission and excitation spectroscopy, we reveal multiple energy transfer processes between Er 3+ and CsPbBr 3 QDs under different excitation wavelengths in Er 3+ doped CsPbBr 3 QDs glass: under higher energy excitation (∼378 nm), energy transfer from Er 3+ to CsPbBr 3 QDs and this extra energy within CsPbBr 3 QDs decay via a non-radiative pathway; under lower energy excitation (∼524 nm), energy transfer from conduction band of CsPbBr 3 QDs to 4 S 3/2 energy level of Er 3+ which significantly enhances PL emission of Er 3+ in near infrared region (∼1535 nm, 4 I 13/2  →  4 I 15/2 ). These results provide a facile approach to enhance and regulate PL emission of Er 3+ in near infrared region.