Samarium doping improves luminescence efficiency of Cs3Bi2Br9 perovskite quantum dots enabling efficient white light-emitting diodes

Abstract

Considering the toxicity problem of lead-based perovskite quantum dots (PQDs), the lead-free Cs3Bi2Br9 PQDs has been recognized as one of the promising candidates. However, the low photoluminescence quantum yields (PLQYs) hinder its practical application in optoelectronic devices. Here, we successfully prepared Sm3+ ions doped Cs3Bi2Br9 PQDs with effective white light-emission by modified ligand-assisted recrystallization method. The realization of white light-emission is attributed to the broadband blue emission of excitons and the red emission (4G5/2–6HJ (J = 5/2, 7/2, 9/2)) of Sm3+ ions for Sm3+ ions doped Cs3Bi2Br9 PQDs. More importantly, compared with the undoped Cs3Bi2Br9 PQDs, the PLQYs of Sm3+ ions doped Cs3Bi2Br9 PQDs are improved from 10.9% to 20.8%, and the anti-water stability is also obviously improved. Finally, the Sm3+ ions doped PQDs based white light-emitting diodes (LEDs) with luminous efficiency of 12.6 lm/W were explored, which indicates that there is a potential prospect of lead-free PQDs in white light lighting application.