RESUMEN
The surface treatment and effect of Sr-doping in nano TiO2 photoanodes based dye-sensitized solar cell (DSSC) is investigated for enhancing the power conversion efficiency (PCE), by the effect of reduced charge recombination and fast photoelectron moving. Sr doped TiO2, enhances the DSSC performance, due to the increase in bang gap energy and its fermi energy level alignment, which is observed from current density-voltage (J-V), Electrochemical impedance spectroscopy (EIS) and the incident photon-to-current conversion efficiency (IPCE) measurements. 5 at. % of Sr-doped TiO2 with titanium tetrachloride (TiCl4) treatment exhibits the highest PCE of 9.6%, which is 249% and 40% higher than that of undoped bare and TiCl4 treated TiO2 photoanodes, respectively. The fast charge separation capability is examined from dielectric behaviour. Overall investigation obviously ascribes that the effect of doping and an additional layer on the photoanodes are responsible for the enhanced stability and high-power conversion efficiency of TiO2 based DSSCs.
RESUMEN
Degradation of metal-organic halide perovskites when exposed to ambient conditions is a crucial issue that needs to be addressed for commercial viability of perovskite solar cells (PSCs). Here, a concept of encapsulating CH3NH3PbI3 perovskite crystals with a multi-functional graphene-polyaniline (PANI) composite coating to protect the perovskite against degradation from moisture, oxygen and UV light is presented. Hole-conducting polymers containing 2D layered sheet materials are presented here as multi-functional materials with oxygen and moisture impermeability. Specific studies involving PANI and graphene composites as coatings for perovskite crystals exhibited resistance to moisture and oxygen under continued exposure to UV and visible light. Most importantly, no perovskite degradation was observed even after 96 h of exposure of the PSCs to extremely high humidity (99% relative humidity). Our observations and results on perovskite protection with graphene/conducting polymer composites open up opportunities for glove-box-free and atmospheric processing of PSCs.