ARTICLE pubs.acs.org/JPCC
Computational Study of Absorption Energies of Organic Sensitizers Used in Photovoltaic Applications Mannix P. Balanay and Dong Hee Kim* Department of Chemistry, Kunsan National University, Kunsan, 573-701, South Korea
bS Supporting Information ABSTRACT: An assessment of several range-separated (RSH) DFT functionals, such as LC-ωPBE, LC-BLYP, ωB97X-D, and CAM-B3LYP, in predicting the excited-state energies of organic sensitizers containing 2-cyano-3-(thiophen-2-yl)acrylic acid was performed. The choice of RSH DFT functional with an optimized separation parameter, ω, is crucial for calculating the excitation energies of organic dyes with extended π-conjugation. The optimized ω for TD-LC-ωPBE, TD-LC-BLYP, and TDωB97X-D RSH functionals are the same for both HQ-1 and HQ-2, where HQ-2 has an added thiophene moiety at the πbridge. On the other hand, for the TD-CAM-B3LYP RSH functional, HQ-2 yielded a larger ω than HQ-1. For ground-state geometry optimization, those DFT functionals with 50% HartreeFock exchange showed a good correlation with the MP2optimized geometries. Among the methods used, TD-LC-ωPBE/6-31+G(d)//mPWPW91α50/6-31G(d) in a solvent effect with ω = 0.20 Bohr1 gave the best accuracy of
