Application of benz[c,d]indolenine-based unsymmetrical squaraine dyes to near-infrared dye-sensitized solar cells

Novel benz[c,d]indolenine-based unsymmetrical near-infrared squaraine dyes having germinal butyl (eta = 0.55%) and octyl (eta = 0.58%) groups at another indolenine ring exhibited higher conversion efficiency than the usually used methyl derivative (eta = 0.38%). The germinal butyl and octyl groups can inhibit aggregation formation and approaching I-3(-) species to improve the conversion efficiency. (C) 2017 Elsevier Ltd. All rights reserved.