Figure 2

Structure of CdS QDs/SiO2 thin films and electron transfer scheme.
(a) Structure of CdS QDs/SiO2 thin films. The average diameters of SiO2 particles and CdS QDs were 20 nm and 2.4 nm, respectively. (b) Energy diagram of the electron transfer process from CdS QDs to bipyridinium derivatives. (c) Chemical structure of N,N’-bis(3-sulfonatopropyl)-2,2′-bipyridinium (DQS).