Higher open-circuit voltage set by cobalt redox shuttle in SnO_2 nanofibers-sensitized CdTe quantum dot solar cells

In this study, we report an efficient CdTe-SnOquantum dot（QD） solar cell fabricated by heat-assisted drop-casting of hydrothermally synthesized CdTe QDs on electrospun SnOnanofibers. The as-prepared QDs and SnOnanofibers were characterized by dynamic light scattering（DLS）, UV–Vis spectroscopy,photoluminescence（PL） spectra, X-ray diffraction（XRD） and transmission electron microscopy（TEM）. The SnOnanofibers deposited on fluorine-doped tin oxide（SnO） and sensitized with the CdTe QDs were assembled into a solar cell by sandwiching against a platinum（Pt） counter electrode in presence of cobalt electrolyte. The efficiency of cells was investigated by anchoring QDs of varying sizes on SnO. The best photovoltaic performance of an overall power conversion efficiency of 1.10%, an open-circuit voltage（Voc）of 0.80 V, and a photocurrent density（JSC） of 3.70 m A/cmwere obtained for cells with SnOthickness of5–6 μm and cell area of 0.25 cmunder standard 1 Sun illumination（100 m W/cm）. The efficiency was investigated for the same systems under polysulfide electrolyte as well for a comparison.

In this study, we report an efficient CdTe-SnO_2 quantum dot(QD) solar cell fabricated by heat-assisted drop-casting of hydrothermally synthesized CdTe QDs on electrospun SnO_2 nanofibers. The as-prepared QDs and SnO_2 nanofibers were characterized by dynamic light scattering(DLS), UV–Vis spectroscopy,photoluminescence(PL) spectra, X-ray diffraction(XRD) and transmission electron microscopy(TEM). The SnO_2 nanofibers deposited on fluorine-doped tin oxide(SnO_2) and sensitized with the CdTe QDs were assembled into a solar cell by sandwiching against a platinum(Pt) counter electrode in presence of cobalt electrolyte. The efficiency of cells was investigated by anchoring QDs of varying sizes on SnO_2. The best photovoltaic performance of an overall power conversion efficiency of 1.10%, an open-circuit voltage(Voc)of 0.80 V, and a photocurrent density(JSC) of 3.70 m A/cm^2 were obtained for cells with SnO_2 thickness of5–6 μm and cell area of 0.25 cm^2 under standard 1 Sun illumination(100 m W/cm^2). The efficiency was investigated for the same systems under polysulfide electrolyte as well for a comparison.