Enhanced Light‐Harvesting Capability of a Panchromatic Ru(II) Sensitizer Based on π‐Extended Terpyridine with a 4‐Methylstylryl Group for Dye‐Sensitized Solar Cells

• DOI: 10.1002/adfm.201202504
• Publication Date: 2012-11-02T09:35:42Z
• Authors: Youhei Numata; Surya Prakash Singh; Ashraful Islam; Munetaka Iwamura; Atsushi Imai; Koichi Nozaki; Liyuan Han
• Keywords: Terpyridine; HOMO/LUMO; Panchromatic film; Open-circuit voltage

Abstract A novel Ru π‐expanded terpyridyl sensitizer, referred to as HIS‐2, is prepared based on the molecular design strategy of substitution with a moderately electron‐donating 4‐methylstyryl group onto ligand. The HIS‐2 dye exhibits slightly increased metal‐to‐ligand charge transfer (MLCT) absorption at around 600 nm and an intense π–π* in UV region compared black dye. Density functional theory calculations reveal that lowest unoccupied orbital (LUMO) distributed over terpyridine moieties, which enhances light‐harvesting capability appropriate for smooth electron injection from TiO 2 conduction band. incident photon‐to‐electricity conversion efficiency spectrum better photoresponse whole spectral result extended π‐conjugation. DSC device gives short‐circuit current ( J SC ) 21.28 mA cm −2 , open‐circuit voltage V OC 0.69 V, fill factor (FF) 0.72, overall η 10.5%. In contrast, cell higher value 23.07 0.68 FF 0.71, owing improved 11.1% achieved.