Lanthanide‐Based Lead‐Free Perovskite Materials for Visible‐Range and Infrared Light‐Emitting Diodes

Abstract Owing to rich 4 f‐ 4 f transitions, lanthanide‐based perovskite nanomaterials endow the perovskite family with highly expanded optical and photoelectrical properties. It is significant to comprehensively understand these kinds of semiconductor materials and explore their applications. In this paper, 42 kinds of lanthanide coordination perovskite materials (LCPMs) are developed with the typical chemical formula Cs ₃ LnX ₆ (Ln = La, Ce…Lu, X = Cl, Br, I). The Cs ₃ LnX ₆ nanocrystals (NCs) show a tunable direct bandgap of 3.1–3.7 eV, demonstrating efficient broadband emissions of the host and sharp lines of lanthanide ions from visible to near‐infrared. A mechanism including self‐trapped exciton emission and the Föster energy transfer process between exciton and lanthanide ions is proposed based on ultrafast dynamics and theoretical calculations. Finally, the LCPMs are used to fabricate the single‐component electroluminescent tunable blue, white, and infrared Light‐Emitting Diode (LED) devices, which demonstrate the optimum external quantum efficiency (EQE) of 5.5%. The infrared electroluminescence of 986, 1064, 1301, and 1540 nm coming from Yb ³⁺ Nd ³⁺ , Pr ^3+, and Er ³⁺ are obtained for the first time in the lead‐free provskite based LEDs with the optimum EQE of 0.71% for 1540 nm LED. This paper provides new researsh ideas for novel semiconductor nanomaterials.