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.