Influence of surfactants on electrochemical growth of CdSe nanostructures and their photoelectrochemical performance

Cadmium selenide (CdSe) thin films were grown by electrochemical technique on fluorine-doped tin oxide (FTO)-coated conducting glass substrates in the presence of organic surfactants. The influence of organic surfactants like polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) on different physico-chemical properties and its subsequent impact on photoelectrochemical (PEC) performance of CdSe thin films have been investigated. It has observed that the organic surfactants play an important role in modifying the surface morphology of CdSe thin films. The compact grain like morphology of pure CdSe is tuned to interconnected nanofibrous network on addition of PEG and to sprouting nanorods like morphology on addition of PVP. Among these nanostructures, CdSe sprouting nanorods exhibits improved power conversion efficiency of 0.55% as compared to nanofibrous (0.24%) and granular CdSe (0.16%) nanostructures. It reveals the fourfold enhancement in the PEC performance on PVP-mediated growth which can be attributed to conversion of compact dense nanostructure to porous and relatively high surface area nanostructure. This work exemplifies the ability of organic surfactant to modulate the surface morphology of the electrodeposits and pinpoints the organic surfactant that gives rise to the suitable morphology for PEC solar cell application.