Tunable and Efficient Photoluminescence of Lanthanide-Doped Cs₂NaScCl₆ Double Perovskite Single Crystals toward Multifunctional Light-Emitting Diode Applications

Abstract

Lead-free halide double perovskite, as one of the promising candidates for lead halide perovskite materials, shows great potential in light-emitting diodes (LEDs), benefiting from its environmental friendliness and high chemical stability. However, the poor regulation of the emission spectra severely limits its application range. Herein, various lanthanide ions were successfully doped in Cs2NaScCl6 double perovskite single crystals (DPSCs) to yield effective and stable emissions spanning from visible to near-infrared (NIR) regions. Notably, efficient energy transfer from the host to the dopants enables tunable emissions with good chromaticity, which is rarely reported in the field of lead-free double perovskite. Moreover, density functional theory calculations reveal that the high local electron density around the [LnCl6]3– octahedron in DPSCs plays a key role in the improvement of photoluminescence quantum yields (PLQYs). The optimal PLQYs are up to 84%, which increases around 3 times over that of the undoped sample. Finally, multicolor and NIR LEDs based on Ln3+-doped Cs2NaScCl6 DPSCs were fabricated and had different application functions. Specifically, the single-composite white LED shows adjustable coordinates and correlated color temperatures, while the NIR LED shows good night vision imaging. This work provides new inspiration for the application of efficient multifunctional LEDs based on lead-free double perovskite materials.

Tuning the Physical Properties of Lead-Free Halide Double Perovskite Cs2MInCl6 (M = Na, K) via Cu Doping for Optoelectronic Applications: ADFT Investigation

“…It is clear that the structural symmetry gets distorted upon doping, which in turn promotes electron localization. These induced localized electrons will play a significant role in improving the PLQY of the doped DPs . The optimization curve (Figure ; energy (eV/atom) versus volume (Å 3 /atom)) provides information on the relaxed crystal structure, which is obtained using the Birch–Murnaghan third-order equation of states (EOS) P ( V ) = 3 2 B 0 [ ( V 0 / V ) 7 / 3 − ( V 0 / V ) 5 / 3 ] { 1 + 3 4 false( B 0 ′ − 4 false) false[ false( V 0 / V false) 2 / 3 − 1 false] } As presented in Figure , the energy (eV/atom) of the optimized structure increases with increasing Cu concentration.…”

Excitation-dependent efficient photoluminescence in an organic–inorganic (C4H12N)2HfCl6 perovskite induced by antimony doping

“…Chemical doping is an effective strategy for tailoring the electronic and optical properties of metal halides. 15–21 For example, antimony (Sb 3+ ) ions with ns 2 electronic configurations can be used to confer superb light-emitting properties to materials, typically including efficient broadband STE emission. 22–27 For these halide perovskite materials, excitons are absolutely confined in isolated polyhedrons with strong quantum confinement, ultimately producing only a single STE emission at room temperature and no emission of high-energy free excitons (FEs).…”

K-Alloyed Lead-free Double-Perovskite Cs2AgBiBr6 Nanocrystals for Use in Light-Emitting Diodes

“…As a result, perovskite materials find applications in photovoltaics and electronics, including lasers, photodetectors, solar cells, and light-emitting diodes (LEDs). , Besides their appealing applications, perovskite can be readily prepared using various methods such as solution-based and vacuum-based techniques, ultrasonic methods, hydrothermal methods, and thermal injection. , However, the toxicity and susceptibility to heat and humidity of lead present limitations for practical applications. Consequently, several strategies have been developed to enhance the stability and reduce the toxicity of halide perovskites. − …”