Compact ultrabroadband light-emitting diodes based on lanthanide-doped lead-free double perovskites

Impurity doping is an effective approach to tuning the optoelectronic performance of host materials by imparting extrinsic electronic channels. Herein, a family of lanthanide (Ln(3+)) ions was successfully incorporated into a Bi:Cs2AgInCl6 lead-free double-perovskite (DP) semiconductor, expanding the spectral range from visible (Vis) to near-infrared (NIR) and improving the photoluminescence quantum yield (PLQY). After multidoping with Nd, Yb, Er and Tm, Bi/Ln: Cs(2)AglnCl(6) yielded an ultrabroadband continuous emission spectrum with a full width at half-maximum of similar to 365 nm originating from intrinsic self-trapped exciton recombination and abundant 4f-4f transitions of the Ln(3+) dopants. Steady-state and transient-state spectra were used to ascertain the energy transfer and emissive processes. To avoid adverse energy interactions between the various Ln(3+) ions in a single DP host, a heterogeneous architecture was designed to spatially confine different Ln(3+) dopants via a DP-in-glass composite (DiG) structure. This bottom-up strategy endowed the prepared Ln(3+) -doped DIG with a high PLQY of 40% (nearly three times as high as that of the multidoped DP) and superior long-term stability. Finally, a compact Vis-NIR ultrabroadband (400 similar to 2000 nm) light source was easily fabricated by coupling the DiG with a commercial UV LED chip, and this light source has promising applications in nondestructive spectroscopic analyses and multifunctional lighting.

Automated summary

Impurity doping has been used effectively to enhance the optoelectronic performance of lead-free double perovskite semiconductors, with multidoping of lanthanide ions leading to broadening of the emission spectrum and improved photoluminescence quantum yield. The use of a heterogeneous structure helped avoid adverse energy interactions and achieve high luminescence efficiency and long-term stability, making it promising for nondestructive spectroscopic analyses and multifunctional lighting applications.