Hole transporting dye as light harvesting antenna in dye sensitized TiO2 hybrid solar cells
(English)Manuscript (preprint) (Other academic)
The pore volume in solid state dye-sensitized solar cells can be utilized for light harvesting by using hole transporting dyes (HTD) in addition to interface dyes (ID) bound to the surface of the meso-porous metal oxide scaffold. Triphenyl-amine based compounds were used both as HTD (TPTPA) and ID (D5L0A3). Energy transfer from the HTD to ID was investigated using steady state photoluminescence. The photoluminescence of the HTD is quenched in presence of the ID – both for samples where the HTD and ID were dispersed in a solid PMMA matrix and for solid samples measured on ZrO2 films. The regeneration of oxidized ID by the HTD after photo-induced electron injection into TiO2 was investigated using nanosecond transient absorption spectroscopy. In presence of the HTD signals, attributed to oxidized ID, vanished while spectral signatures suggesting the creation of oxidized HTD appeared. In solar cell devices comprising both the ID and HTD the spectral response of the external quantum efficiency shows that both dyes contribute to the photocurrent resulting in a 2-fold increase in photocurrent. The interface dye seems to prevent recombination giving rise to a higher open circuit voltage in the solar cell devices. Due to the increase both in photocurrent and voltage the solar cell device performance increased by a factor of 3. Utilizing a hole-transporting dye in addition to an interfacial sensitizer is a promising design concept for solid state dye sensitized solar cell devices.
IdentifiersURN: urn:nbn:se:uu:diva-168484OAI: oai:DiVA.org:uu-168484DiVA: diva2:498341