Zinc oxide nanoparticles with intentionally introduced defects for applications in white LEDs

A rapidly developing market of white LEDs requires new solutions for replacing the rare earth-based phosphors, as 95 % of these materials come from China, creating a monopoly disadvantageous for other countries and a risk for the wide deployment of white LED technology in the coming years. Ona alternative to these rare-earth based phosphors is ZnO. It is a wide bandgap semiconductor, cheap, non-harmful and abundant in nature and it can emit visible light, from yellow to red, depending on the nature of the crystalline and surface defects [1]. IRCELyon recently developed a quick and convenient chemical sol-gel approach to obtain a unique mesospheric self-assembly of ZnO nanoparticles in a hybrid system with intense and stable photoluminescent quantum yield (PL QY) of 40-75 % [1]. This high PL QY is possible thanks to a so-called down-shifting (DS) process, a variant of the down-conversion. This synthesis route uses the mixture of commercially available polyacrylic acid (PAA)-based polymers and can provide large scale amounts of ZnO NPs in clear water suspensions which can be dried and dispersed again in water without compromising the performance (e.g. transparency and PL QY) of the final DS layer. We present the effects of the ZnO NPs surface functionalization and the influence of various doping atoms in ZnO NPs on their photoluminescence spectrum and the PL QY, in order to be able to favor and boost a desired color of emission. References: 1.Y. Zhu, A. Apostoluk, P. Gautier, A. Valette, T. Cornier, J. Bluet, K. Masenelli-Varlot, S. Danièle, B. Masenelli, Scientific Reports 6, pp. 23557 (1-11), 2016.

Aleksandra Apostoluk (1) , Yu Zhang (1) , Nicolas Le Bail (2) , Thibaut Cornier (2) , S. Daniele (2) , Bruno Masenelli (1)

1 INL - S&N - INL - Spectroscopies et Nanomatériaux
2 CDURABLE - IRCELYON-C'Durable

Domaines: Sciences de l'ingénieur [physics]; Matériaux; Optique / photonique; Micro et nanotechnologies/Microélectronique

Aleksandra Apostoluk, Yu Zhang, Nicolas Le Bail, Thibaut Cornier, S. Daniele, et al.. Zinc oxide nanoparticles with intentionally introduced defects for applications in white LEDs. Congrès C'Nano 2017, Dec 2017, Villeurbanne, France. ⟨hal-01849579⟩