Luminescent properties of PMMA-based nanocomposites doped with Pr3+:YF3-Y2O3 nanocrystallites

Optically active composite materials, which are a combination of two different phases with different optical and mechanical properties - for example, a polymer matrix with embedded active nanocrystallites, may enable designing and development of an entirely new class of light sources, combining advantages of small size, low price and excellent optical and mechanical properties. Such a materials can be widely applied in modern optical telecommunications systems (e.g. LANs based on polymer fibers), integrated optoelectronics, optical information processing and many others. The first reports of research on active nanocrystallites doped with rare earth ions dispersed in liquid polymer matrix can be find in R.S. Meltzer works from 2001 [1] and J.W. Stouwdam group papers [2]. The work of the latter team resulted in construction of the planar amplifier based on PMMA doped with Nd³⁺:LaF₃ [3]. In the following years luminescent properties of polymer composites doped with active nanocrystallites were studied, among others, by teams of Kumar [4], Gruber [5], Boyer [6] and Piramidowicz [7]. These results (which are the achievements of only a few research groups working intensively in the last few years on active composite materials) shows that nanoparticle-polymer composites combine the advantages of both polymers (good processability and good mechanical properties) and inorganic luminescent materials (high luminescence efficiency and long-term chemical stability) which may enable development of the new generation of optical materials.In this work we report the recent results of our investigation on visible emission of the PMMA-based nanocomposites doped with YF3, YF3-Y2O3 (YOF) and Y2O3 activated with Pr3+ ions, synthesized from the single-source precursor. Praseodymium dopant offers excellent emission properties in the visible (blue, green and red) spectral range, reported for different low phonon hosts - bulk crystals, glasses and fibers. What is speci- ically interesting, the luminescent properties of Pr3+ depend strongly on the local coordination of active ion in the crystallographic structure of the host. In particular, it has been shown that in several sesquioxides Pr3+ ions exhibit efficient red luminescence from 1D2 level, while the 3P0 emission is totally quenched (e.g. in Y2O3, Gd2O3). The opposite behavior has been reported about the excellent blue-green luminescence from 3PJ manifold with partial or total quenching of 1D2 emission (e.g. in La2O3, LaAlO3).