A controllable and reversible phase transformation between all-inorganic perovskites for white light emitting diodes

Abstract

<p>A controllable and reversible phase transformation between CsCu₂I₃ and Cs₃Cu₂I₅ is employed to fabricate electroluminescent WLEDs for the first time.</p>

Research progress of full electroluminescent white light-emitting diodes based on a single emissive layer

“…In addition to the monochromatic emitting characteristics of perovskites, as generally considered, their broadband-spectrum luminescence performance has also attracted the attention of researchers. As we proposed above, a single layer with broadband-light emission is considered to be an ideal strategy to achieve SEL–WLEDs, e.g., perovskite materials with the characteristics of self-trapped excitons (STEs) 26 , 28 , 29 , 84 , 86 . STEs are often generated in organic molecular crystals, condensed rare gases, and halide crystals owing to lattice distortion 88 , 89 .…”

“…8t, u ). Some perovskite-like materials such as caesium copper halides (CsCu 2 I 3 /Cs 3 Cu 2 I 5 ) have also been developed in WPeLEDs owing to their STE-based broadband light emission from an SEL 29 , 84 , 86 . In a very recent work, Chen H. et al introduced an organic additive into CsCu 2 I 3 /Cs 3 Cu 2 I 5 , resulting in trap-state reduction and PLQY promotion from 18% to 30% 29 .…”

Enhanced Responsivity of CsCu2I3 Based UV Detector with CuI Buffer‐Layer Grown by Vacuum Thermal Evaporation

“…[ 17–20 ] Among them, cesium copper iodine perovskites with CsCu 2 I 3 phase and Cs 3 Cu 2 I 5 phase are of great interest due to their lead‐free and high atmospheric stability. [ 21–26 ] Furthermore, as the promising candidate of yellow‐emitting perovskite materials, CsCu 2 I 3 has drawn more and more attention due to the high yellow PLQYs and color rendering index. [ 27,28 ] However, it is hard to obtain pure CsCu 2 I 3 because CsCu 2 I 3 and Cs 3 Cu 2 I 5 usually coexist.…”

“…[ 27,28 ] However, it is hard to obtain pure CsCu 2 I 3 because CsCu 2 I 3 and Cs 3 Cu 2 I 5 usually coexist. [ 22,26 ] Although many efforts have been made to obtain pure CsCu 2 I 3 , including “CsI/CuI‐stripping” processes, [ 22,26 ] it remains a challenge to get pure CsCu 2 I 3 with high quality by solution method.…”

Towards next generation white LEDs: optics-electronics synergistic effect in a single-layer heterophase halide perovskite

“…Since the dawn of the first semiconductor light-emitting diodes (LEDs), these devices showed many advantages over traditional incandescent or fluorescent lighting, such as high luminous efficiency, energy saving, and color quality 1 . Traditional approach to realize white LEDs (WLEDs) relies on the down-conversion of light emitted by a combination of red (R) and green (G) phosphors excited by blue (B) light, or on electrical excitation of RGB emitters arranged into LED arrays 2,3 . However, the use of the rare-earth elements in down-conversion devices faces issues of high cost and scarcity, and the most common blue-emitting component of such LEDs (GaN) is fabricated through rather expensive epitaxial growth techniques.…”