Thienochrysenocarbazole based organic dyes for transparent solar cells with over 10% efficiency

Abstract

The simultaneous realization of both high-efficiency and long-term durability of transparent, colorful dye-sensitized solar cells (DSSCs) is of paramount importance to gradually supersede the aesthetically repulsive silicon solar cells for future building integrated photovoltaic (BIPV) applications. In this paper we synthesize two donor–acceptor organic dyes C296 and C298 characteristic of a polycyclic heteroaromatic unit 6,11-dihydrothieno[3′,2′:8,9]chryseno[10,11,12,1-bcdefg]carbazole (TCC) as the primary electron-releasing unit, in conjunction with the 4-(benzo[c][1,2,5]thiadiazol-4-yl)benzoic acid (BTBA) and 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid (BTEBA) electron acceptors. Both dyes possess suitable energy gaps, reasonably long excited state lifetimes, and high charge separation yields, allowing for the fabrication of transparent DSSCs with over 10% power conversion efficiencies under the illumination of 100 mW cm⁻², AM1.5G sunlight for the first time. The see-through DSSCs based on the TCC dye with BTEBA as the electron acceptor display good efficiency retention after full sunlight soaking at 60 °C for 1000 h.