Theoretical Study of Torsional Disorder in Poly(3-alkylthiophene) Single Chains: Intramolecular Charge-Transfer Character and Implications for Photovoltaic Properties
被引:24
作者:
Bjorgaard, Josiah A.
论文数: 0引用数: 0
h-index: 0
机构:
N Dakota State Univ, Dept Chem & Biochem, Fargo, ND 58108 USAN Dakota State Univ, Dept Chem & Biochem, Fargo, ND 58108 USA
Bjorgaard, Josiah A.
[1
]
Kose, Muhammet E.
论文数: 0引用数: 0
h-index: 0
机构:
TUBITAK Natl Metrol Inst, TR-41470 Gebze, Kocaeli, TurkeyN Dakota State Univ, Dept Chem & Biochem, Fargo, ND 58108 USA
Kose, Muhammet E.
[2
]
机构:
[1] N Dakota State Univ, Dept Chem & Biochem, Fargo, ND 58108 USA
The role of polymer chain morphology on the optoelectronic properties of polythiophenes is an ongoing investigation with the promise of improving organic photovoltaic performance. Chain morphology is predominantly affected by torsional disorder, which causes localization of holes and electrons in the conjugated backbone. Using the model compound oligo(3-methylthiophene), torsionally disordered oligomers were created to compare with a trans-planar oligomer such as found in crystalline poly(3-hexylthiophene). Low lying electronic excitations are calculated using TD-HF and TD-DFT with various long-range corrected functionals. Probability densities of electron and hole were constructed from natural transition orbitals, giving insight into localization and electron-hole overlap. Overlap is found to be substantially higher in disordered oligomers, indicating a stronger Coulombic interaction between electron and hole. Results suggest that improved photovoltaic performance with increased crystallinity is partially explained by stronger light absorption in crystalline polymers and a higher barrier to charge separation in disordered polymers.