폴리에틸렌글리콜 구조를 갖는 공흡착제를 티타늄디옥사이드 나노구조에 흡착시킨 염료감응 태양전지의 특성 규명

Abstract

Dye sensitized solar cells (DSSC) have been fabricated based on nanocrystalline TiO2 film with ruthenium dye, (cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)-ruthenium(II) bis-tetrabutylammonium (referred as N719), and a novel oligomeric co-adsorbent. The co-adsorbent has oligomeric PEG (poly(ethylene glycol)) chain at the end of molecule and succinic acid at the other end. DSSC showed better performance with the co-adsorbent, resulting from the enhanced open circuit voltage and short circuit current density. This can be explained by the enhanced dye adsorption on TiO2 surface and by the reduced electron recombination rate and negatively shift of the fermi level of TiO2. In addition, we compared the co-adsorbent adsorption method on TiO2 surface to optimize the processing conditions. When we adsorbed the co-adsorbent to the TiO2 surface with different methods and concentrations, they show different tendency of open circuit voltage and the short circuit current density. Consequently, the sequential adsorption method (method A) shows better the open circuit voltage than the simultaneous adsorption one (method B). The best results using the sequential adsorption method were the open circuit voltage of 0.76 V, short circuit current density of 11.0 mA/cm2 and photovoltaic conversion efficiency of 5.7 % under simulated full sunlight (air mass 1.5, 100 mW/cm2).