Effective infrared emission of erbium ions doped inorganic lead halide perovskite quantum dots by sensitization of ytterbium ions

Rare earth ions doped all-inorganic lead halide perovskite quantum dots (PeQDs) have attracted extensive attention due to the rare earth ions doping greatly expanding the optical properties of PeQDs. Here, Er3+ and Yb3+ ions co-doped CsPbCl3 PeQDs are synthesized by the improved hot-injection method. The excitonic emission and near-infrared (NIR) IIb emission of Er3+ ions and quantum-cutting emission of Yb3+ ions were observed in CsPbCl3:Yb3+, Er3+ PeQDs. Interestingly, the NIR IIb emission of Er3+ ions is only obtained in PeQDs through the effective sensitization of Yb3+ ions. The energy transfer efficiency from Yb3+ to Er3+ ions is 23.5%. Furthermore, the optimal photoluminescence quantum yield (PLQY) of a NIR IIb emission for Er3+ ions was got by typical anion exchange reaction, and the value is up to 14.6%. This work provides a new way that further extends the emission wavelength of PeQDs to NIR IIb region, which will broaden the application scope of PeQDs.