Self-assembled CdS quantum dots-sensitized TiO2 nanospheroidal solar cells: Structural and charge transport analysis

Abstract A nanospheroidal TiO 2 mesoporous layer combined with cadmium sulfide (CdS) quantum dots (QDs) as a sensitizer was firstly utilized for solar cell applications, resulting in an efficiency of 1.2% at a 1 sun condition. CdS quantum dots (∼18 nm) were attached to the TiO 2 nanospheroidal electrode by using a chemical bath deposition technique. The influence of surface treatment using dimethyl formamide on the interconnectivity of the TiO 2 nanospheroidal electrodes was investigated. The charge transport of TiO 2 /CdS QDs/electrolyte sandwich-type cells was characterized by electrochemical impedance spectroscopy and the device performance was compared with conventional nanospherical TiO 2 (Degauusa P25) electrodes. The electrodes with nanospheroidal morphology showed better device performance than the P25 nanoparticle electrodes primarily due to both better connectivity among nanospheroidal TiO 2 particles and larger mesopores, resulting in deeper penetration of the electrolyte in QD-sensitized solar cells.

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