Improving near-infrared luminescence in Er(3+) doped CsPbBr(3) 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.