Calculations Of The Excited-state Electronic Structure For Fullerene And Its Derivatives

We have studied the excited-state electronic structures of C6o、C70、PC61BM and PC71BM molecules with first-principles calculations. The ionization potential, electron affinity and the chemical hardness are calculated with the△-SCF method. The UV-Vis-NIr spectra are calculated with the time-dependent density functional theory (TDDFT) for C60、C70and PC61BM. The results coincide with the existing experimental data fairly well, and thus indicate that first-principles calculations are competent to predicting low-energy excited-state properties of fullerenes and their derivatives.The most important result of this thesis is as follows. We find that the electrons of the side chain of PC61BM directly participate in the transition in the UV-Vis-NIr region. This offers an important routine to design the acceptor materials for organic solar cells.