Synthetic Metals 195 (2014) 102–109 Contents lists available at ScienceDirect Synthetic Metals jo ur nal homep age: www.elsevier.com/locate/synmet Fluorescence quenching in PVK:ZnSe nanocomposite structure Zied Ben Hamed a , Aida Benchaabane a , Fayc ¸ al Kouki a,c,∗ , Mohamed Abderahmen Sanhoury b , Habib Bouchriha a a Laboratoire de Matériaux Avancés et Phénomènes Quantiques, Département de Physique, Faculté des Sciences de Tunis, Université Tunis El-Manar, Tunis, Tunisia b Laboratoire de Chimie Organique Structurale et Macromoléculaire, Faculté des Sciences de Tunis, Université de Tunis El Manar, Campus Universitaire, 2092 Tunis, Tunisia c Institut Préparatoire aux Etudes d’Ingénieur El-Manar, Université de Tunis El Manar, Campus Universitaire, 2092 Tunis, Tunisia a r t i c l e i n f o Article history: Received 27 November 2013 Received in revised form 14 March 2014 Accepted 7 May 2014 Keywords: Nanocomposites Fluorescence quenching FRET PVK ZnSe a b s t r a c t The role of the inclusion of ZnSe nanoparticles (NPs) into conducting poly (9-vinylcarbazole) (PVK) on the fluorescence emission has been investigated. The optical properties such as emission and absorp- tion of PVK:[ZnSe] nanocomposites were found to be strongly dependent on the concentration of ZnSe NPs embedded in the PVK matrix. The study was carried out on the PVK:[ZnSe] nanocomposite both in solution and in solid thin film states. The fluorescence spectra are found to be strongly altered upon the embedding of ZnSe nanoparticles into the PVK host matrix. In the solution form, the fluorescence spectra of the nanocomposite with different concentration of NPs undergo dramatic changes both in shape and in intensity. It’s found that the adjunction of small fraction of ZnSe nanoparticles quenches considerably the PVK fluorescence at the expense of an exhalation of the NPs fluorescence especially for low concentrations. This trend is described within the Förster formalism which involves non-radiative energy transfer from the donor (PVK) to the acceptor (ZnSe NPs). In the thin film form the fluorescence and absorption spectroscopy characterizations show the formation of complexes between ZnSe NPs and PVK. The modified Stern–Volmer model is used to interpret the fluorescence quenching in PVK:[ZnSe] nanocomposites thin films. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Nowadays a large amount of publications is devoted to the development of nanocomposite materials of a new type. Nano- hybrid materials based on the embedding of mineral NPs into an organic matrix were considered in various configurations [1–4]. The spatial arrangement of the NPs in the organic matrix is one of the most important factors that affect the efficiency of function- ing devices. Another important issue which may have an effect on the optoelectronic proprieties of such nanocomposites is the effec- tiveness of excitation energy transfer from the matrix (donor) to the NPs (acceptor) [5]. Fluorescence quenching of organic matrix by various quenchers has been studied by several groups [6,7]. There are, therefore, various processes that govern the fluorescence quenching like intersystem crossing, formation of charge transfer ∗ Corresponding author at: Laboratoire de Matériaux Avancés et Phénomènes Quantiques, Département de Physique, Faculté des Sciences de Tunis, Université Tunis El-Manar, Tunis, Tunisia. Tel.: +216 55 907 332. E-mail address: f.kouki@ipeim.rnu.tn (F. Kouki). complexes both at ground and excited states, static and dynamic quenching, etc. Apart from this, the polarity and the temperature of the solvent medium and the range of quencher concentra- tion are also expected to play an important role in this domain. Dynamic quenching refers to any non-radiative process in which the quencher interacts with the excited state of the fluorophore [8]. However, several other significant dynamic quenching mech- anisms exist, such as Förster Resonant Energy Transfer (FRET) or photoinduced electron transfer, which do not require direct con- tact between the fluorophore and the quencher. Static quenching refers to any mechanism that inhibits the formation of the excited state of the fluorophore [8]. The total steady-state fluorescence is obviously reduced, since the fluorophore-quencher complexes are non-fluorescent. In many cases, these so-called ground-state complexes can lead to changes in the absorbance spectrum of the fluorophore [9,10]. The aim of the present work is the investigation of the quenching phenomena in a nanocomposite structure based on polyvinylcar- bazole (PVK) and ZnSe NPs. The whole work is done in the sake of a clearer understanding of the mechanisms that govern the flu- orescence of our nanocomposite structure. For that purpose the http://dx.doi.org/10.1016/j.synthmet.2014.05.010 0379-6779/© 2014 Elsevier B.V. All rights reserved.