Influence of Synthesis Conditions on the Photoluminescence of Poly(methyl methacrylate)/(ZnxCd1 –x)S Compositions

Abstract

Quantum dots (QDs) synthesized by combining semiconductors are characterized by more stable optical properties. Introducing them into polymeric matrices can lead to optical compositions with predictable physical and chemical properties. These properties are largely determined by the method and conditions of synthesis of compositions. It has been demonstrated how the composition of reaction mixtures, the sequence of their preparation, and heating have an effect on the composition, structure, and photoluminescence properties of (ZnxCd1 –x)S QDs in polymeric compositions based on poly(methyl methacrylate) (PMMA). The QDs have been synthesized in situ in a methyl methacrylate (MMA) medium. Sulfides are formed during the destruction of thioacetamide metal complexes. The formation of QDs continues during thermal curing of the compositions to the glassy state. As a response to changes in the synthesis conditions, the changes in the photoluminescence and photoluminescence excitation spectra of PMMA/(ZnxCd1 –x)S compositions have been considered. The deactivation of excited electronic states occurs with the participation of energy levels of defects located on the energy diagram of the compositions in the band gap of semiconductor QDs. The luminescence spectrum is predominantly determined by CdS and defects on the surface of its crystals. Based on the data obtained, formulas are proposed that reflect the composition and structure of composites formed under various synthesis conditions.