title: Molecular design of near-IR harvesting unsymmetrical squaraine dyes.
abstract: The functionalized unsymmetrical benzothiazole squaraine organic sensitizers 5-carboxy-2-({3-[(3-hexylbenzothiazol-2(3H)-ylidene)methyl]-2-hydroxy-4-oxo-2-cyclobuten-1-ylidene}methyl)-1-hexyl-3,3-dimethyl-3H-indolium (hereafter named as SK-11) and 5-carboxy-2-({3-[(3-hexyl-5-methoxybenzothiazol-2(3H)-ylidene)methyl]-2-hydroxy-4-oxo-2-cyclobuten-1-ylidene}methyl)-1-hexyl-3,3-dimethyl-3H-indolium (coded as SK-12) 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.
authors.affiliation: Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409, USA.
authors.forename: Sanghoon
authors.initials: S
authors.lastname: Kim
authors.forename: Gopal K
authors.initials: GK
authors.lastname: Mor
authors.forename: Maggie
authors.initials: M
authors.lastname: Paulose
authors.forename: Oomman K
authors.initials: OK
authors.lastname: Varghese
authors.forename: Chul
authors.initials: C
authors.lastname: Baik
authors.forename: Craig A
authors.initials: CA
authors.lastname: Grimes