Ce:YAG composites for white LED

Abstract

Composites and luminescent polymers have been recently found to be potential candidates for the development of white LED, lasers and luminescent concentrators for solar cells. Due to its luminescence properties YAG doped with lanthanides ions is a good candidate as light emitting filler. In a recent our work, the preparation of a polymeric nanocomposite containing Ce:YAG nanoparticles using in situ polymerization has been reported [1]. A good dispersion of Ce:YAG nanoparticles has been obtained maintaining them luminescence properties. In addition, an increase of thermal stability and stiffness of PMMA was observed [2]. Then, the preparation of Ce:YAG-PMMA composite has been performed by using the melt compounding method, which is not expensive, allows to obtain big quantitative of material, and limit the exposition at the carcinogenic monomer metyl-methacrylate used as starting precursor in the in situ polymerization [3]. In this work the preparation of Ce:YAG-PMMA and of Ce:YAG-PC composites by using the melt compounding method at several amount of Ce:YAG in the range 0.1-5 wt.%. is reported. Structure, morphology, thermal and mechanical properties of the composites were investigated. The optical properties of the obtained composites and of the composites combined with a blue LED were measured to investigate the effect of the Ce:YAG amount on the resulting emitted light in view of possible applications. Results showed that the particles are homogenously dispersed in each polymer and that the thermal stability of the polymer and the optical properties depend on the filler quantity. Acronym: YAG: yttrium aluminum garnet; PMMA: Polymethylmethacrylate; PC: polycarbonate. References [1] M.L. Saladino, A. Zanotto, D. Chillura Martino, A. Spinella, G. Nasillo, E. Caponetti, Langmuir Vol.26(16) (2010) 13442–13449. [2] A. Zanotto, A. Spinella, G. Nasillo, E. Caponetti, A.S. Luyt, EXPRESS Polymer Letters Vol.6(5) (2012) 410-416. [3] M.L. Saladino, D. Chillura Martino, M.A. Floriano, D. Hreniak, L. Marciniak, W. Stręk, E. Caponetti, The Journal of Physical Chemistry C, Vol. 118 (2014) 9107−9113.