Regioselective Synthesis of 1,2- vs 1,3-Squaraines
作者:Elisabetta Ronchi、Riccardo Ruffo、Silvia Rizzato、Alberto Albinati、Luca Beverina、Giorgio A. Pagani
DOI:10.1021/ol201093t
日期:2011.6.17
Squaraines have been known for many decades as very stable and versatile vis-NIR absorbing dyes. They have found applications for example as sensitizers in organic photovoltaics and photodetectors. The most common squaraine structure is the 1,3-regioisomer. Their 1,2-regiolsomers are seldom mentioned and unanimously regarded as side products. A facile direct synthesis of 1,2-squaraines, highlighting the role played by reaction conditions and electronic factors, is described. The first electrochemical characterization of these dyes is also shown.
Molecular Design of Near-IR Harvesting Unsymmetrical Squaraine Dyes
作者:Sanghoon Kim、Gopal K. Mor、Maggie Paulose、Oomman K. Varghese、Chul Baik、Craig A. Grimes
DOI:10.1021/la101257b
日期:2010.8.17
The functionalized unsymmetrical benzothiazole squaraine organic sensitizers 5-carboxy-2-(3-[(3-hexylbenzothiazol-2(3H)-ylidene}methyl]-2-hydroxy-4-oxo-2-cyclobuten-l-ylidenelmethyl)-1-hexy1-3,3-dimethyl-3H-indolium (hereafter named as SK-11) and 5-carboxy-2-0-[(3-hexyl-5-methoxybenzothiazol-2(311)-ylidene)methyl]-2-hydroxy-4-oxo-2cyclobuten- 1-ylidenelmethyl)-1-hexy1-3,3-dimethyl-3H-indolium (coded as SK-I2) are designed and developed to observe an intense and wider absorption band in the red/NIR wavelength region. DFT/TDDFT calculations have been performed on the two unsymmetrical squaraine sensitizers to gain insight into their electronic and optical properties. The utility of these dyes in solid state dye sensitized solar cells (SS-DSSCs) is demonstrated.