Low-lying excited states of Diphenylpolyenes and its derivatives in singlet fission: A Density Matrix Renormalization Group study

Abstract

Singlet fission (SF) is a promising mechanism by which the power conversion efficiency (PCE) of the solar cells can be increased. α, ω-Diphenylpolyenes are known to draw research attention due to their fascinating optical and photophysical properties. The low-lying excited states of 1,6-diphenyl-1,3,5-hexatriene (DPH), 1,8-diphenyl-1,3,5,7-octatetraene (DPO), 1,10-diphenyl-1,3,5,7-decapentaene (DPD) molecules and their derivatives are calculated within Pariser–Parr–Pople(PPP) model Hamiltonian implementing Density Matrix Renormalization Group (DMRG) technique. The calculations reveal that all three molecules are promising candidates for SF mechanism. Excited state energies in singlet subspace have been calculated for 1,6-diphenyl-1,3,5-hexatriene (DPH) comprising 18 carbon atoms within exact diagonalization method which are in excellent agreement with results obtained in DMRG technique. Moreover, calculations on α, ω-diphenyl-μ, ν-dicyano oligoenes (DPDCs) show with increasing chain length, these derivatives support endoergic to isoergic SF