DFT and TD-DFT design of small π-conjugated molecules with narrow band gap and high efficiency for organic solar cells
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Five copolymers noted cop 1, cop 2, cop 3, cop 4 and cop 5 are theoretically designed. Each has a D–π–A architecture based on triarylamine used as a donor unit D for its high charge carrier mobility and its excellent stability, and five heterocyclic acceptors A with high carriers mobility. The aim is searching narrow band and high efficiency donor materials for organic photovoltaic cells. Using density functional theory DFT and time-dependent density functional theory TD-DFT, molecular orbitals, electronic and optical properties, exciton binding energies and charge transfer process are all predicted for all copolymers. The results show that all copolymers can be used with (PCBM) to design organic heterojunction photovoltaic cells. While comparing the various copolymers, we have noticed that cop 2 and cop 5 show the best optical properties, exciton dissociation and holes transport capability is more favorable for them, which improves short-circuit current (Jsc) and a fill factor (FF). Finally, the power conversion of composites involving cop 2/PCBM as well as cop 5/PCBM, respectively 8% and 9%, provides their efficiency. These results demonstrate that cop 2 and cop 5 will be two promising candidates for organic photovoltaic performance devices.
KeywordsDensity functional theory Low band gap Intermolecular charge transfer Donor–acceptor Organic solar cells
We would like to thank Pierre Girard for technical support in the context of the Grenoble Centre d’Experimentation du Calcul Intensif en Chimie (CECIC) computers used for the calculations reported here.
- 10.Sharma GD, Mikroyannidis JA, Sharma SS, Thomas KRJ (2012) Bulk heterojunction organic photovoltaic devices based on small molecules featuring pyrrole and carbazole and 2-(4-nitrophenyl)acrylonitrile acceptor segments as donor and fullerene derivatives as acceptor. Dyes Pigm 94:320–329CrossRefGoogle Scholar
- 39.Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Mennucci B, Petersson GA et al (2009) Gaussian09 revision D.01. Gaussian Inc., WallingfordGoogle Scholar
- 53.Walker B, Liu J, Kim C, Welch GC, Park JK, Lin J, Zalar P, Proctor CM, Seo JH, Bazan GC, Nguyen T-Q (2013) Optimization of energy levels by molecular design: evaluation of bis-diketopyrrolopyrrole molecular donor materials for bulk heterojunction solar cells. Energy Environ Sci 6:952–962CrossRefGoogle Scholar