Synthesis of near-infrared silver-indium-sulfide (AgInS2) quantum dots as heavy-metal free photosensitizer for solar cell applications

We report the use of silver-indium-sulfide (AgInS2) quantum dots (QDs) as heavy metal-free photosensitizer for QDs-sensitized solar cell. For fabricating the TiO2/AgInS2 electrode, the QDs were attached to a mesoporous TiO2 surface by using bifunctional linker molecules. The fabricated TiO2/AgInS2 electrode exhibits light absorption in the visible region and serves as the photoanode. Upon bandgap excitation, injection of photoexcited electrons from AgInS2 QDs into the TiO2 matrix produces photocurrents accordingly. The proof-of-concept AgInS2 QDs-sensitized solar cell exhibits a short-circuit current of 0.49 mA/cm2 and open-circuit voltage of 0.24 V, under one sun illumination.