Thermally Stable Quantum Rods, Covering Full Visible Range for Display and Lighting Application

Abstract

Recently, quantum rods (QRs) have been studied heavily for display and lighting applications. QRs offer serious advantages over the quantum dots such as higher light out‐coupling coefficient, and polarized emission. The QR enhancement films double liquid crystal display efficiency. However, it is still a challenge to synthesize good quality green (λem ≈ 520 nm) and blue (λem ≈ 465 nm) emitting QRs, due to very large bathochromic shift during the shell growth. Furthermore, until now, the presence of cadmium in high‐quality QRs is inevitable, but due to its toxicity, RoHS has restricted the amount of cadmium in consumer products. In this article, low Cd core‐shell QRs, with a narrow‐band luminescence spectrum tuned in the whole visible range, are prepared by replacing Cd with Zn in a one‐pot post‐synthetic development. These QRs possess the good thermal stability of photoluminescence properties, and therefore, show high performance for the on‐chip LED configuration. The designed white LEDs (WLEDs) are characterized by a high brightness of 120000 nits, and color gamut covering 122% NTSC (90% of BT2020), in the 1931CIE color space. Additionally, these LEDs show a high luminous efficiency of 115 lm W−1. Thus, these quantum rod LED are perfectly viable for display backlighting and lighting applications.

Quantum‐Rod On‐Chip LEDs for Display Backlights with Efficacy of 149 lm W−1: A Step toward 200 lm W−1

“…The method is based on Cd to Zn cation exchange in a one‐pot postsynthetic procedure. [ 36 ] These QRs show better thermal stability in comparison to the conventional CdSe/CdS core–shell QRs. The details can be found in ref.…”

“…The details can be found in ref. [ 36 ] . The QRs for the LED application, as stated above, has three basic problems, i.e., the emission wavelength, low PLQY in solid (film) state, [ 37 ] and stability (thermal and photo).…”

Monodisperse CuInS2/CdS and CuInZnS2/CdS Core–Shell Nanorods with a Strong Near‐Infrared Emission

“…Moreover, NRs can be assembled into highly ordered arrays, where their parallel alignment enables a high degree of emission polarization that can be applied to improve efficiency of liquid crystal displays. [ 3–6 ] One prominent example of brightly emitting semiconductor NRs are core–shell heterostructured nanoparticles termed “dot‐in‐rod,” which can be produced by seeded growth synthesis. In 2007, Carbone et al.…”

“…Moreover, NRs can be assembled into highly ordered arrays, where their parallel alignment enables a high degree of emission polarization that can be applied to improve efficiency of liquid crystal displays. [3][4][5][6] One prominent example of brightly emitting semiconductor NRs are core-shell heterostructured nanoparticles termed "dot-in-rod," which can be produced by seeded growth synthesis. In 2007, Carbone et al and Talapin et al independently reported a type I heterostructure comprising CdSe/ CdS dot-in-rods, with a high degree of control over the rod dimensions and photoluminescence quantum yields (PL QY) ranging from 50% to 80%.…”

Inkjet printed patterned bank structure with encapsulated perovskite colour filters for modern display

“…To date, a variety of colour conversion materials are applied in displays combined with UV or blue excitation from InGaN and GaN LEDs to produce vivid colours. [20][21][22][23] II-VI group Cd based QDs, such as CdSe/CdS have been widely explored in past years due to their excellent quantum efficiency (up to film state 99% QY). The thermal quenching of these particles can be reduced by covering them with wider bandgap shell materials, e.g.…”