Ultrafast electron injection kinetics and effect of plasmonic silver nanoparticle at organic dye-TiO2 interface

In this mini review, we present the investigations on the electron injection kinetics of two thioalkyl substituted tetrathiafulvalene dye molecules in mesoporous TiO2 layers for dye-sensitized solar cells (DSSCs). Steady-state absorption and photoluminescence (PL) spectroscopy techniques were employed to apprehend the excited state dynamics of the molecules as thin-film deposited on quartz and mesoporous TiO2 layers. Time-resolved PL measurements at the “dye-TiO2” interface provided initial evidence of electron injection by fast PL quenching decay dynamics for both the molecules. Detailed target analysis of the femtosecond transient absorption spectroscopy (TAS) data of the “dye-TiO2” sample showed a multi-step ultrafast electron injection for both molecules where the fastest injection components were ≈374 fs and ≈314 fs for G1 and G3 molecules, respectively. Furthermore, the introduction of silver nanoparticles (AgNPs) at the dye-TiO2 interface resulted in surface plasmon resonance induced ultrafast and enhanced electron-injection and reduced charge-recombination dynamics. We observed improved light trapping and hot electron injection from Ag NPs to TiO2. © Anita Publications. All rights reserved.