Functionalized carbon dots on TiO2 for perovskite photovoltaics and stable photoanodes for water splitting

Various types of fluorescent carbon nanoparticles, often called dots (CDs), are synthesized by different polycondensation methods: microwave irradiation, hydrothermal conditions or solution chemistry at ambient temperature with subsequent chemical functionalization. The CDs deposited on TiO2 films to be probed as electron transport layers in perovskite photovoltaics and the anode for photoelectrochemical water splitting. Nitrogen CDs, which do not contain oxygen, lead an increase around 50 mV open circuit voltage solar cells. All CD produce improved photocurrent splitting, particularly that functionalized thiol groups butyl chains. It is demonstrated modified electrode stable under continuous operation. Other electrochemical characteristics electrode, such voltammogram shape, onset potentials potentials, remain nearly unchanged upon deposition CDs. Only incident photon current conversion efficiency improves clearly, extending absorption range 20 nm towards longer wavelengths. This study provides new data about mechanisms arrangements improving performance n-type semiconductors photovoltaic cells hydrogen production.