Ultrahigh Color Rendering in RGB Perovskite Micro‐Light‐Emitting Diode Arrays with Resonance‐Enhanced Photon Recycling for Next Generation Displays

Abstract

Light sources with high color purity are promising for revolutionizing traditional displays because of their wide achievable color gamut, high contrast ratio, and good color saturation. The demand for next‐generation displays has driven the development of the optoelectronic materials with narrow linewidth. Until now, most optoelectronic materials usually give emission with full width at half maximum exceeding 30 nm. The lack of a general approach to further improving the color purity has limited their applications for next‐generation displays. Here, a universal resonance‐enhanced photon recycling strategy is developed to realize current‐driven displays with unprecedented high color rendering based on the perovskite light‐emitting diode (LED) arrays in distributed Bragg reflector (DBR) cavity. Benefiting from the outstanding optoelectronic properties and solution processability, perovskites are processed into micro‐LED arrays through a screen‐printing technology. The light output from individual micro‐LED is strongly modulated by resonance‐enhanced photon recycling derived from the cavity structure, leading to significant spectral narrowing and directional emission. On this basis, unprecedented high‐color‐purity is achieved in a prototype of current‐driven display panels. The outstanding performance of red, green, and blue (RGB) micro‐LED arrays with resonance‐enhanced photon recycling provides a deep insight into the design concepts and device structures for next‐generation display technology.

Metal Halide Perovskites toward Electrically Pumped Lasers

“…[246] Subsequently, Liang et al incorporated a bottom DBR under the ITO electrode of the red, green, and blue perovskite micro-LED array, forming a F-P resonant cavity with the metal electrode reflector. [250] Narrowed spectra and directed emission were obtained as a result of resonance-enhanced photon recycling of the cavity (Figure 15c). They demonstrated the microcavity effect and the compatibility of the DBR cavity with perovskite LEDs, although no lasing was achieved.…”

“…Reproduced with permission. [250] Copyright 2021, Wiley-VCH. d) The current density and EL emission intensity versus voltage curves for CsSnBr 3 -based LED.…”

“…c) Schematic illustration of a micro-LED embedded in DBR microcavity and EL spectra of the blue, green, and red emission from as-prepared devices with and without a DBR cavity. Reproduced with permission [250]. Copyright 2021, Wiley-VCH.…”

Microscale Perovskite Quantum Dot Light‐Emitting Diodes (Micro‐PeLEDs) for Full‐Color Displays

“…Inkjet printing (IJP) technology is considered the first choice to prepare single-and self-luminous PeLED pixels, which also promises large-area production. [4,[28][29][30][31][32][33][34][35] Currently, photolithography-inkjet printing (PHO-IJP) is usually used to fabricate a single pixel of conventional semiconductor quantum dots, with pixel pits on a substrate being created by photolithography followed by filling them with ink via inkjet printing. [4,26,[36][37][38][39] The PHO-IJP relies heavily on the expensive photolithography process; it only allows the creation of pixels with sizes larger than 50 μm and is also costly to prepare large-size displays.…”

Spectral Narrowing and Enhancement of Directional Emission of Perovskite Light Emitting Diode by Microcavity

“…[40] On the other hand, all-dielectric DBR PeLEDs are relatively difficult to realize at present due to the issues of fabrication process and material fragility. A better scheme of metaldielectric microcavity [50] can be applied in PeLED by using total reflective metal mirror and dielectric DBR with optimal designs.…”