Morphology dependent photoinduced electron transfer from N,N-dimethylaniline to semiconductor cadmium sulfide

Abstract

Photoluminescence of large (150–200 nm) colloidal CdS nanoparticles in isopropanol was efficiently quenched by the electron donor molecule N,N-dimethylaniline (DMA). The quenching rates were found to be accelerated with improvement of the crystallinity of the CdS substrates. Electron-transfer from DMA to spherical CdS nanoclusters with 2–4 nm polycrystalline domains inside exhibited the slowest quenching rate (k_q ∼ 0.65 × 10¹⁰ M⁻¹ S⁻¹). However the quenching rate was enhanced by ∼2 times (k_q ∼ 1.2 × 10¹⁰ M⁻¹ S⁻¹) when crystal plane alignments were moderately improved. Further improvement of the quenching rate (k_q ∼ 3.5 × 10¹⁰ M⁻¹ S⁻¹) was successfully achieved when the morphology of the CdS substrates was changed to nanorods. This enhancement is attributed to the single crystalline structure i.e. highly ordered crystal planes along the axis of the nanorod.