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

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 17; no. 3; pp. e2004487 - n/a
• Main Authors: Prodanov, Maksym F., Gupta, Swadesh K., Kang, Chengbin, Diakov, Maksym Y., Vashchenko, Valerii V., Srivastava, Abhishek K.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.01.2021
• Subjects: blue emission; Cadmium; Color; Coupling coefficients; LED; Light emitting diodes; Lighting; Liquid crystal displays; low cadmium; Luminous efficacy; Nanotechnology; Photoluminescence; Quantum dots; quantum rods; Rods; Thermal stability; Toxicity; wide color gamut; blue emission; wide color gamut; quantum rods; low cadmium; luminous efficacy; LED; thermal stability
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202004487

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 rods with a narrow thermally stable luminescence tuned in the whole visible range are prepared by replacing Cd with Zn in a one‐pot post‐synthetic development. The quantum rods show high performance in the on‐chip LED configuration covering 122% NTSC in 1931CIE color space with a record‐high luminous efficacy of 115 lm W−1 among the wide color gamut white LEDs.