Functionalized Dendritic Oligothiophenes: Ruthenium Phthalocyanine Complexes and Their Application in Bulk Heterojunction Solar Cells

Abstract

Within the present work, two series of novel ruthenium(II) phthalocyanine (RuPc) complexes with one [RuPcCOPy-nT] or two [RuPc(Py-nT)(2)] dendritic oligothiophene (DOT) ligands in the axial positions are reported. The ability of Ru(II) for axial coordination in RuPcs allowed the attachment of the Pc through the metal site to the DOT-ligands bearing pyridine at the core position of the dendrons. These extended pyridine functionalized conjugated DOT-ligands (Py-nT) were chosen to cover the spectral window between 380 and 550 nm, where the RuPc does not exhibit a strong absorption, in order to improve the light-absorption of these complexes and hence enhance the efficiency of the corresponding solar cells. Good efficiencies of up to 1.6% have been achieved when blended together with a fullerene acceptor in solution-processed photovoltaic devices, providing by far the best phthalocyanine-based bulk heterojunction solar cells reported to-date.

Electronic structure of Fe- vs. Ru-based dye molecules

“…Ru, on the other hand, prefers the +2 oxidation state in OEPs and phthalocyanines. 14,48 As a result, we have only been able to make a direct comparison between Ru 2 + in RuCO-OEP and Fe 3 + in FeCl-OEP. Removal of the Cl from FeCl-OEP without breaking the molecule apart has not been possible (compare Fig.…”

Synthesis, characterization and investigation of electrical and electrochemical properties of imidazole substituted phthalocyanines

“…They have been used in very different areas of technology and medical applications, i.e., gas sensor [1,6,7], liquid crystal [2,8], solar cell [9,10], catalyst [2,5,11], electrochromic display [3,12], photodynamic therapy of cancer [13,14]. Phthalocyanine has been studied with many metal ions and different substituents on peripheral (b) and non-peripheral (a) positions [1][2][3][4][5].…”

Conjugated dendritic oligothiophenes for solution-processed bulk heterojunction solar cells

“…We recently combined thiophene dendron to perylenebisimide dye (PDI) [53] or phthalocyanine core [54,55] via a non-conjugated connection (Fig. 12).…”

“…Therefore, device performance of these dye-functionalized dendrimers is mainly depended on the property of the dye moiety, while thiophene dendron acts as light harvesting antenna. Application of these materials in BHJ solar cells was also tested, and power conversion efficiencies of 0.6%-1.7% were achieved [54].…”