Exploration of nonlinear optical behavior in asymmetric dithieno [3,2b:2',3'd] pyrrole based push pull constrain: A theoretical approach

The organic compounds with end-capped acceptors obtained much consideration in optoelectronic field owing to their promising electronic properties. Herein, a series of PTMD1PTMD6 conjugated compounds having D-p-A architecture were designed via structural tailoring including end-capped acceptors in non-fullerene compound (PTMR). The PTMR and its designed compounds were used at M06/6-311G(d,p) level for their optimization analysis and subsequently, by using optimized geometries to perform non-linear optical (NLO), frontier molecular orbitals (FMOs) and natural bond orbitals (NBOs) analyses. The quantum chemical investigations revealed that all the designed compounds showed significant reduction in band gaps with the range of 1.4671.880 eV in comparison to PTMR (2.308 eV). The band gaps were found as PTMR (2.308) > PTMD6 (1.880) > PTMD1 (1.752) > PTMD2 (1.693) > PTMD4 (1.532) > PTMD5 (1.514) > PTMD3 (1.467) with eV in the descending order. Further, density of states (DOS) supported the results of FMOs study, consequently, according to transition density matrix (TDMs), the designed chromophores (PTMD1-PTMD6) displayed the transmission of charge effectively. The PTMD3 showed the maximum value of lambda(max) at 764.627 nm as compared to all the designed derivatives with greater bathochromic shift. The compound PTMD3 showed the highest values of beta(tot) and < gamma > among all the studied compounds i.e., 7.695 x 10(-27) and 1.776 x 10(-3)1 esu, respectively.

Automated summary

A series of PTMD1PTMD6 conjugated compounds with D-p-A architecture were designed, including end-capped acceptors in non-fullerene compound (PTMR). Quantum chemical analysis showed significant reduction in band gaps for all the designed compounds compared to PTMR, with range of 1.467-1.880 eV. The designed chromophores (PTMD1-PTMD6) exhibited effective charge transmission and greater bathochromic shift.