Highly Bright and Stable Lead‐Free Double Perovskite White Light‐Emitting Diodes

Abstract

Lead‐free double perovskites (DPs) are emerging highly stable emitters with efficient broadband self‐trapped exciton (STE) photoluminescence (PL), but their low electroluminescent (EL) efficiency is a critical shortcoming. We promoted the external quantum efficiency (EQE) and luminance of DP‐based white light‐emitting diode (wLED) with a normal device structure to 0.76% and 2793 cd m−2 via two modifications: We prevented the formation of adverse metallic silver, spatially confined STE, and lowered local site symmetry in Cs2Na0.4Ag0.6In0.97Bi0.03Cl6 DP by terbium doping; and we developed a guest‐host strategy to improve film morphology, reduce defect density and increase carrier mobility. These alterations caused substantial increases in STE radiative recombination and charge injection efficiency of perovskite layer. Finally, pure white EL with ideal color coordinates of (0.328, 0.329) and a record‐breaking optoelectronic performance was achieved by introducing additional green carbon dots in LED to fill the deficient green component.This article is protected by copyright. All rights reserved

Ce3+-Activated SrLu2Al3ScSiO12 Cyan-Green-Emitting Garnet-Structured Inorganic Phosphor Materials toward Application in Blue-Chip-Based Phosphor-Converted Solid-State White Lighting

“…Presently, the assembly of commercially available blue light InGaN LED chips and the yellow Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) phosphor is the mainstream approach to fabricate warm white-light-emitting diodes (WLEDs). , However, the lack of a red component in the resulting spectrum of YAG:Ce 3+ causes the LED device to exhibit poor CRI, normally below 80, and high correlated color temperature, usually greater over 5000 K. , Although the addition of an additional commercial red-emitting CaAlSiN 3 :Eu 2+ phosphor in the above scheme is a simple and effective way to optimize Ra and CCT, it is impossible to obtain satisfactory Ra values (>95) due to the presence of a cyan gap in 480–520 nm region. , This pain point for the LED industry seriously hinders its further commercial application in photography, museums, art galleries, backlighting, and medical lighting. − In response to the issues mentioned above, two feasible approaches have been proposed by researchers to fabricate high-performance WLEDs toward a more comfortable illumination. One of the approaches is combining near-ultraviolet (near-UV) LED chips with tricolor phosphors (blue, green, and red). − Another option is employing the blue light chip to pump the mixed phosphors with red and green emission .…”

Cs2Cd1–xMnxCl4 Nanoplatelets for Thermal Quenching Resistance and Luminescence Tuning

“…The implementation of doping strategies can effectively enhance its current state and confer novel properties onto this material. To enhance material properties, doping is a commonly used strategy. , Due to the high defect tolerance of perovskite materials, Cs 2 CdCl 4 has been doped with Mn 2+ and Sb 3+ . Liu et al investigated the temperature-dependent optical properties of single-doped samples and found excellent thermal quenching resistance, while Huang et al achieved emission tuning and long afterglow emission with zero quenching characteristics by adjusting doping concentration .…”

Crown-Assisted CsCu2I3 Growth and Trap Passivation for Perovskite Light-Emitting Diodes

“…13 Moreover, double perovskites, 14,15 such as Cs 2 AgInCl 6 and Cs 2 NaInCl 6 , are formed by replacing two Pb 2+ cations with one monovalent cation and one trivalent cation. 16 The wide full width at half-maximum (FWHM) of PL due to the self-trapped exciton is beneficial to realize highefficiency white-light emission. 17 Some lead-free perovskites are based on the elements in III−V groups and transition metals, such as Sb 3+ , 18,19 Bi 3+ , 20 and In 3+ , 21 which tend to form low-dimensional perovskites on account of the different valence states from Pb 2+ .…”

“…Sn-based red-light PeLEDs have realized enhanced EQE values over 20%, and Ge-based perovskites show the potential to realize white-light-emitting diodes and indoor photovoltaics . Moreover, double perovskites, , such as Cs 2 AgInCl 6 and Cs 2 NaInCl 6 , are formed by replacing two Pb 2+ cations with one monovalent cation and one trivalent cation . The wide full width at half-maximum (FWHM) of PL due to the self-trapped exciton is beneficial to realize high-efficiency white-light emission .…”