Enhanced efficiency of quantum dot sensitized solar cells using Cu 2O/TiO 2 nanocomposite photoanodes

摘要

AbstractSeveral quantum dot sensitized solar cells (QDSSCs) were fabricated by doping Cu2O nanoparticles (NPs) into the TiO2photoanode pastes in order to improve their efficiencies. The QDSSCs were made using the CuS counter electrode and sulfide/polysulfide electrolyte. The inclusion of Cu2O NPs in the photoanodes of both CdS and CdSe QDSSCs was found to increase the photocurrent and efficiency. The XPS analysis approved that the Cu2O particles were successfully impregnated on the TiO2NPs. Results indicated that the photovoltaic parameters of the optimized CdSe cell (η?=?3.01%, JSC?=?10.2?mA?cm?2, VOC?=?0.59?V, FF?=?0.50) were boosted compared with those of the reference cell which was free of Cu2O (η?=?1.88%, JSC?=?7.0?mA?cm?2, VOC?=?0.56?V, FF?=?0.48) signifying about 60, 46 and 5% improvements in efficiency, current density and open-circuit voltage, respectively. The lowest intensity of the photoluminescence (PL) peak for the cell fabricated using 0.03% Cu2O doped TiO2suggested that it had the least charge recombination and the easiest electron transfer which was confirmed by the J-V and efficiency data. The electrochemical impedance spectra (EIS) proved that the electron life time was considerably improved by approximately ten times in the optimized cell (τe?=?60.0?ms) compared with that of the cell fabricated only using TiO2(τe?=?5.8?ms). Thus, addition of 0.03%wt Cu2O as a dopant was very appropriate to attain suitable photocurrent efficiency for the QDSSCs because it could be used in a minimum amount to improve the electron transport, drop the recombination and increase the cell efficiency.Graphical abstractDisplay OmittedHighlights?Several QDSSCs were fabricated by Cu2O doping into the TiO2photoanode.?TEM images indicated that photoanode nanocomposite particles were ?20–35?nm.?The optimized CdSe cell provided the η?=?3.01% with the JSC?=?10.2?mA?cm?2.?The highest efficiency was measured for the cell made using 0.03% Cu2O