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Research Article Open Access

Electronic levels of small molecules for organic solar cells: A computational study

Shahjad1, 2, Ranoo Bhargav1, 2, Dinesh Bhardwaj1, 2, Asit Patra1, 2*



1Academy of Scientific and Innovative Research (AcSIR), CSIR-National Physical Laboratory Campus,
Dr. K. S. Krishnan Marg, New Delhi-110012, India

2Flexible Organic Energy Devices, Advanced Materials and Devices, CSIR-National Physical Laboratory,
Dr. K. S. Krishnan Marg, New Delhi-110012, India

Adv. Mater. Proc., 2017, 2 (5), 294-298

DOI: 10.5185/amp.2017/503

Publication Date (Web):05 May 2017

Copyright © IAAM-VBRI Press



Currently significant progress has been made for the small molecules, indeed, achieved comparable performance compared to polymer in electronic devices mainly due to the many advantages of small molecules over the polymers. Designing better small molecules for electronic applications are required a comprehensive understanding of the structure-properties relationship and the factors affecting it. Valuable information can be generated directly toward understanding by systematically theoretical and experimental studies (band gap, HOMO, LUMO energy levels and geometry). Hybrid density functional B3LYP level of theory is a very good method for predicting the reliable geometry, electronic structure and properties of conjugated systems. In the present work, we have calculated the band gaps, highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and geometry of a series of small molecules based on oligothiophene, benzodithiophene and dithienosilole unit using the hybrid density functional (B3LYP/6-31G(d)) level of theory and correlated with experimental values. The study provides details for the effect of the extended conjugation, two-dimension conjugation, substitution on geometry, HOMO, LUMO and band gaps of the small molecules. Copyright © 2017 VBRI Press.


Density functional calculations, small molecules, photovoltaic, band gap, geometry.