Butterfly-inspired micro-concavity array film for color conversion efficiency improvement of quantum-dot-based light-emitting diodes

Abstract

Inspired by the Papilio blumei butterfly, quantum-dot (QD) film coupled with micro-concavity array (MCA) films is proposed in this Letter to enhance color conversion efficiency (CCE) of QD-based light-emitting diodes (LEDs). The diameter, aspect ratio, and pitch of the MCA are optimized in the optical simulations. Both the simulation and experimental results show that the scattering and double reflection effects are the key to the CCE improvement of QD films. The results show that the CCEs are increased from 19.98% to 21.59% and 21.78% (350 mA) for single-sided microstructured QD film and double-sided microstructured QD film configurations, respectively. Overall, the MCA film is a promising solution to enhance the CCE of QD-based LEDs.

Hierarchical Disordered Colloidal Thin Films with Duplex Optical Elements for Advanced Anti‐Counterfeiting Coding

“…For example, iridescence, [ 3 ] non‐iridescence, [ 4 ] mixed [ 5 ] or dynamic [ 6 ] colors, chirality, [ 7 ] polarization, [ 8 ] ultra‐blackness, [ 9 ] or other optical effects [ 10 ] derived from these multi‐scale nanomaterials, and are important for camouflage, mating, warning, signaling, or thermoregulation of the creatures. [ 8,11 ] Inspired by these fascinating photonic structures, great efforts have been devoted to mimicking the micro‐/nano‐architectures to realize corresponding optical properties or functions, [ 10c,11b,12 ] which have spurred the development of next‐generation photonic sensors, [ 13 ] displays, [ 13b,14 ] and photovoltaics. [ 15 ] In particular, hierarchical photonic superstructures (HPSs) with multiple optical elements [ 12f,13 b, 15a,16 ] provide delicate optical features derived from collective optical functions, which could be precisely engineered by variations of the physical parameters at the nanoscale, and therefore are of great potential for highly secure anti‐counterfeiting.…”

Enhanced Photoluminescence in Quantum Dots–Porous Polymer Hybrid Films Fabricated by Microcellular Foaming

“…In recent years, colloidal quantum dots (QDs) have emerged as an alternative to conventional rare‐earth phosphors in display and general illumination applications due to their outstanding properties, such as broad absorption band, narrow emission linewidth, tunable peak emission wavelength, and high photoluminescence quantum yield (PLQY) . In such applications, QDs are dispersed into a polymeric matrix to form hybrid films, which usually serve as free‐standing, remote‐type configurations excited by an external UV/blue light source . In this layout, the light conversion process is notably hindered by the limited absorption of the excitation light by the QDs.…”

Microlens arrays with adjustable aspect ratio fabricated by electrowetting and their application to correlated color temperature tunable light-emitting diodes

“…The LED technology offers unique advantages compared to traditional incandescent bulbs and fluorescent lamps including a high efficiency, a low power consumption and a long lifetime [6][7][8][9]. To meet the demands of high-quality illumination and display, the angular color uniformity (ACU) of LEDs needs further improvement [10][11][12]. Numerous methods have been proposed to ameliorate the ACU of white LEDs, such as light scattering nano-particles [13,14], shaped phosphor layers [15,16], diffusing reflectors [17] and microstructured films [18,19].…”