Non-toxic silver iodide (AgI) quantum dots sensitized solar cells

• We have demonstrated AgI sensitized solar cell for the first time.
• Obtained mesoporous titania powders possessed small crystallite size, high purity and surface area, and developed mesopores with a narrow pore size distribution.
• Photovoltaic measurements revealed the electron injection from AgI to TiO2.
• The assembled AgI-QD solar cells yielded a power conversion efficiency of 0.64% under one sun illumination.
• AgI may be a suitable candidate material for use as a non-toxic sensitizer in QDSSC.

The present study reports the performance of a new photosensitizer -AgI quantum dots (QDs)- and mesoporous titania (TiO2) nanocrystals synthesized by sol–gel (SG) method for solar cells. Furthermore, the effects of n-heptane on the textural properties of TiO2 nanocrystals were comprehensively investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2 adsorption–desorption measurements, and UV–vis spectroscopy. TiO2 powders exhibited an anatase-type mesoporous structure with a high surface area of 89.7 m2/g. Afterwards, the QDs were grown on mesoporous TiO2 surface to fabricate a TiO2/AgI electrode by a successive ionic layer adsorption and reaction (SILAR) deposition route. Current–voltage characteristics and electrochemical impedance spectroscopy (EIS) data demonstrated that the injection of photoexcited electrons from AgI QDs into the TiO2 matrix produces photocurrents. The assembled AgI-QD solar cells yielded a power conversion efficiency of 0.64% and a short-circuit current of 2.13 mA/cm2 under one sun illumination.

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