Synthesis of solid solutions of Cd1−xZnxS nanocrystals in the channels of mesostructured silica films

Abstract

In this contribution, we introduce the use of metal ion (Cd(II) and Zn(II)) modified mesostructured silica as a reaction medium, to produce a solid solution of Cd_1−xZn_xS nanocrystals as a thin film. With this approach, a true liquid crystalline templating (TLCT) and liquid crystalline mesophase of transition metal salt ∶ oligo(ethylene oxide) non-ionic surfactant (((1 − x)[Cd(H₂O)₄](NO₃)₂ + x[Zn(H₂O)₆](NO₃)₂) ∶ CH₃(CH₂)₁₁(OCH₂CH₂)₁₀OH, (MLC)), systems were collectively used to synthesise mesostructured silica films. The film samples were reacted at room temperature (RT) in an H₂S atmosphere to produce zinc blend Cd_1−xZn_xS nanocrystals in the channels of mesostructured silica. The initial Zn(II) and Cd(II) ion concentrations in the reaction media determine the final composition and band gap of the Cd_1−xZn_xS nanocrystals. The growth process of the Cd_1−xZn_xS nanocrystals in the pores is influenced by the silica walls. If the walls are rigid (well polymerized, obtained by aging the samples before H₂S treatment), then the Cd_1−xZn_xS nanoparticles are smaller in size and more uniform in size distribution.