Cobalt-doped CsPbBr3 perovskite quantum dots for photoelectrocatalytic hydrogen production via efficient charge transport

Photoelectrochemical cells (PECs) based on all-inorganic perovskite quantum dots (QDs) have great potential for the catalytic splitting of water using sunlight due to their good photovoltaic properties and inexpensive manufacturing process. However, their development is severely constrained by their own large carrier transport barriers and poor water stability. Herein, we report the synthesis of cobalt doped CsPbBr3 perovskite quantum dots (Co-doped CsPbBr3 QDs) by hot-injection method and their preparation into FTO/c-TiO2/m-TiO2/Co-CsPbBr3 QDs photoanode devices, and further encapsulation of the devices using low-temperature conductive carbon paste (LTCC). The partial replacement of Pb2+ sites by Co2+ in Co-doped CsPbBr3 QDs with appropriate concentrations enhances the binding energy of QDs, forms impurity energy levels, reduces carrier transport barriers, improves carrier lifetime and carrier separation and transport rate, so as to improve optoelectronics purpose of catalytic activity. Ultimately, the Co-CsPbBr3 QDs photoanode produced 1.944 mA cm−2 at 1.23 VRHE under simulated sunlight (AM 1.5, 100 mW cm−2) and achieved a stable photocurrent density of more than 1 mA cm−2 for up to 5500 s in aqueous KOH solution. The development of effective all-inorganic perovskite quantum dots sheds light on the realization of catalysts for PEC water splitting.