Strategies towards enhancing the efficiency of BODIPY dyes in dye sensitized solar cells

Abstract

The goal of this study is to reveal the effect of electron donating and anchoring group of the dye on the electron injection dynamics and photovoltaic performance of BODIPY dye sensitized solar cells. The effect of electron donating properties was studied by choosing methoxyphenyl and triphenylamine (TPA) as electron donor moieties. Therefore, four new BODIPY derivatives were designed and sensitized to achieve these goals. In addition, attachment of the dye to TiO2 was studied by altering the surface morphology of TiO2 with fs laser ablation.The steady state absorption and emission spectra, femtosecond transient absorption spectra, incident photon to-current conversion efficiency (IPCE) and I-V measurements of the studied dyes were investigated, systematically. It was found that methoxyphenyl moiety gives better performance than TPA moiety. BODIPY dye with methoxyphenyl moiety and one anchoring group demonstrated the best photovoltaic performance due to greater excited state lifetime in spite of the lower light harvesting ability, as compared to other studied dyes. Increasing the number of anchoring groups did not increase the photovoltaic performance of BODIPY dye with methoxyphenyl moiety. Anchoring efficiency, light-harvesting capability, and electron injection rate to TiO2 were enhanced by femtosecond laser ablation treatment of TiO2 surface. Experimental results proved that power conversion efficiency was increased 47% when photoanode was laser ablation treated.