서강대학교

목차

Dye-sensitized nanoporous TiO2 solar cells (DSSCs) can be classified into two types, namely, Type-I and Type-II. Type-I DSSCs are the DSSCs in which electrons are injected from the adsorbed dyes by photoexcitation of the dyes followed by electron injection from the excited dyes to TiO2 (pathway A). Type-II DSSCs are the DSSCs in which electrons are injected not only by pathway A but also by direct one-step electron injection from the dyes to TiO2 by photoexcitation of the dye-to-TiO2 charge-transfer (DTCT) bands (pathway B). The DSSCs employing catechol (Cat) or its derivatives as the sensitizers have been the typical examples of Type II DSSCs.
We have investigated the influence of electrolyte composition on the photovoltaic
performance of a cat-v-Q sensitized solar cell (DSSC). We have also spectroscopically
investigated the interaction between the electrolyte components and the adsorbed dye. The absorption peaks attributed to the DTCT band of cat-v-Q dye in adsorbed on a TiO2 film, was increased in the presence of Li cations, which led to a positive shift of the conduction band edge of TiO2. And DTCT band was decreased in the presence of TBP (tert-butyl pyridine), which led to a negative shift of conduction band edge of TiO2. The photovoltaic performance of the DSSC based on the cat-v-Q dye depended remarkably on the electrolyte composition. A high solar energy-to-electricity conversion efficiency of 3.82% (Jsc=12.28 mAcm_2, Voc=0.48 and FF=0.64)
Also, other catechol derivatives were synthesized containg thiophen or pydinium / quinolinium salt to observe photovoltaic properties.