Silver nanoparticles-incorporated Nb 2 O 5 surface passivation layer for efficiency enhancement in dye-sensitized solar cells.

Guiding and capturing photons at the nanoscale by means of metal nanoparticles and interfacial engineering for preventing back-electron transfer are well documented techniques for performance enhancement in excitonic solar cells. Drifting from the conventional route, we propose a simple one-step process to integrate both metal nanoparticles and surface passivation layer in the porous photoanode matrix of a dye-sensitized solar cell. Silver nanoparticles and Nb ₂ O ₅ surface passivation layer are simultaneously deposited on the surface of a highly porous nanocrystalline TiO ₂ photoanode, facilitating an absorption enhancement in the 465 nm and 570 nm wavelength region and a reduction in back-electron transfer in the fabricated dye-sensitized solar cells together. The TiO ₂ photoanodes were prepared by spray pyrolysis deposition method from a colloidal solution of TiO ₂ nanoparticles. An impressive 43% enhancement in device performance was accomplished in photoanodes having an Ag-incorporated Nb ₂ O ₅ passivation layer as against a cell without Ag nanoparticles. By introducing this idea, we were able to record two benefits - the metal nanoparticles function as the absorption enhancement agent, and the Nb ₂ O ₅ layer as surface passivation for TiO ₂ nanoparticles and as an energy barrier layer for preventing back-electron transfer - in a single step.
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