Polymer Nanocomposite Based on Styrene with Butyl Methacrylate and Inorganic Semiconductor CdS

Abstract

Abstract. We present experimental results on copolymer-based nanocomposite made of styrene with butyl methacrylate (1:1) and inorganic semiconductor CdS. Thin fi lm composite samples have been characterized by UVVis absorption and photoluminescent spectroscopy, as well as by transmission electron microscopy. Transmission electron microscope examination confi rms a relatively narrow distribution of CdS nanoclusters in the SBMA matrix, which covers the range 2-10 nm. On the other side, the average CdS particles size estimated from the position of fi rst excitonic peak in the UV-Vis absorption spectrum was found to be 2.8 nm and 4.4 nm for two samples with different duration of thermal treatment, which is in good agreement with PL experimental data. The PL spectrum for CdS nanocrystals is dominated by near-band-edge emission. The relatively narrow line width (40-45 nm) of the main PL band suggests the nanoparticles having narrow size distribution. On the other side, relatively low PL emission from surface trap states at longer wavelengths were observed in the region 500-750 nm indicating on recombination on defects.Keywords: nanocomposite, polymer matrix, photoluminescence, exciton. IntroductionNanocomposite (NC) materials belong to one of the most dynamic domain of research and development, and they occupy an important place is the fi eld of nanotechnology [1][2][3][4][5][6]. Nanocomposite materials made of a polymer matrix and an inorganic semiconductor have become a prominent area of research and technology because of their attractive properties [4][5][6]. NCs offer a variety of new possibilities beyond those of conventional materials as well as compared to NCs constituent components. The basic feature of nanoscale materials resides in the possibility of tuning of their physical and chemical properties through varying the size of incorporated nanoparticles. This actually means obtaining different properties within the same chemical composition just by changing the size of nanoparticles [7][8][9][10].Among existing variety of nanocomposite materials polymer based NCs attract a lot of research efforts because of many advantages, compared to conventional materials. These advantages refer to their relatively simple technology, low cost, easy tuning, etc. Polymer NCs can be obtained in the form of thin fi lms, bulk, or fi ber samples, etc., by relatively simple technological methods, among them drop-wise deposition, spin coating, extrusion, etc. Polymer based NC materials with inorganic semiconductors comprise a polymer material as a matrix and incorporated inorganic semiconductor nanoparticles as fi llers [11][12]. The role of the polymer matrix in nanocomposites is to assemble the nanoparticles into clusters, avoiding agglomeration, inducing ordering and orientation in self-assembling structures, etc.As one of the most important II-VI group semiconductors CdS nanoparticles have received great attention because of their attractive properties and potential for application in photonics and optoelectronics [14][15][16]...