A theoretical approach for exploration of non-linear optical amplification of fused azacycle donor based thiophene polymer functionalized chromophores

Abstract

The quantum chemical calculations are executed for a series of designed carbazole-based oligothiophene systems (CPTR1 and CPTD2-CPTD8) having D1-π1-D2-π2-A architecture. The effect of addition of π-linkers on designed architecture for the electronic and non-linear optical response was examined at M06/6-311G(d,p) level of theory. The frontier molecular orbitals (FMOs), density of states (DOS), natural population analysis (NPA), UV–Vis and transition density matrix (TDM) and non-linear optical (NLO) analyses were utilized in order to comprehend key electronic and non-linear optical response. All the designed molecules exhibited a lower energy gap (ELUMO-EHOMO) as 2.434–2.780 eV, as compared to the CPTR1 (2.875 eV). Among all the derivatives, CPTD8 exhibited the highest dipole polarizability 〈α〉 and second hyperpolarizability (γtot) as 2.946 × 10-22 esu and 41.372 × 10-33 esu, respectively. Dipole moment (µ) and first hyperpolarizability (βtot) of CPTD8 were found to be as 3.478 D and 118.886 × 10-29 esu, correspondingly. The second hyperpolarizability (γtot) of CPTD8 was observed to be ∼6.4 ∼4.0 ∼2.5 ∼1.8 ∼1.4 ∼1.3 and ∼1.1 times higher in comparison to CPTR1 and CPTD2-CPTD7, respectively. It is concluded that carbazole-based oligothiophene might be used as a potential material in optoelectronic devices.

Keywords

• Oligothiophene
• Quantum chemical calculations
• Third order NLO
• Charge transfer
• DFT study