Synthesis and Photovoltaic Properties of Novel Ferrocene-Substituted Metallophthalocyanines

In this paper, a series of new metallophthalocyanines including ferrocene groups were designed, synthesized-characterized, and their photovoltaic properties were investigated as alternative electron donor material in bulk heterojunction (BHJ) solar cells. These products were synthesized by a Sonogashira cross-coupling reaction between tetraiodophthalocyanine and ethynyl ferrocene. The newly synthesized phthalocyanines (4-6) were characterized by FT-IR, UV-Vis, 1H NMR and MALDI-TOF spectroscopic methods and elemental analysis as well. The electrochemical characterizations were carried out by using cyclic voltammetry as well as differential pulse voltammetry technique. Density functional theory calculations were realized to prove in the charge separation between ferrocene as electron-donor and phthalocyanine ring as acceptor. According to UV-Vis measurements, a 25 nm red shift was observed for complex 4 compared with the complexes 5 and 6. Finally, the photovoltaic performance of these compounds used as electron donor moiety in BHJ device were investigated. A function of different blend ratio was tested by fabricating a series of BHJ devices with the architecture of FTO/PEDOT:PSS/4-6: PCBM blend/Ag with identical thickness of active layer. Results indicated that the photovoltaic conversion efficiency of BHJ devices exhibited strongly blend ratio dependence. Maximum power conversion efficiency was obtained by 5 based devices as 3.65 % with blend ratio of 1.5:1.0 under standard AM 1.5 illumination