Preparation of Ag@Au core-shell nanoparticles embedded in TiO2 inverse opal for light harvesting and efficiency enhancement in quantum dot sensitized solar cells

In the fabrication of Quantum dot sensitized solar cells (QDSSCs), it is important to fabricate a photoanode with a high ability to trap photons as well as transfer photogenerated electrons. TiO ₂ inverse opal (TIO) photonic crystals with their organized porous structures, besides their chemical nature, have unique optical features such as the slow-photon effect, photon localization, and photonic bandgap (PBG). Herein, to improve the efficiency of QDSSCs, gold, silver, and silver/gold core-shell (Ag@Au) plasmonic nanoparticles (nps) are loaded on TIO. The plasmonic nanoparticle-decorated inverse opal improves the light scattering process and provides direct charge transfer tunnels, which can effectively prevent the recombination of electron-hole pairs. In this work, fabricated QDSSCs with TIO (double-layer)/ZnS/CdS/CdSe/ZnSe/ZnS photoanode, and a 6 μm total thickness of the TIO multilayer, has an open circuit voltage (V _oc) of 0.745 V and short-circuit current density (J _SC) of 16.22 mA/cm ². The obtained results are higher than the common anatase TiO ₂ (TiO ₂-A)/ rutile TiO ₂ (TiO ₂-R)/QD photoanode. Also, the TIO (double-layer)/Ag@Au/QDs photoanode exhibits J _SC=20.3283 mA/cm ², V _oc= 0.75 V, and a power conversion efficiency (PCE) of ƞ=10.79 %.