Journal Article intramolecular charge transfer (ICT) organic electronics COSMO D (donor)-Pyrene (bridge)-A (acceptor) DFT Diketopyrrolopyrrole Hammett theory MoS2 PCM Para–Nitroaniline QM/MM ab initio methods bulk heterojunction (BHJ) charge transfer states cluster optimum size diketopyrrolopyrrole discrete and continuum solvation models donor properties electronic absorption spectra energetic materials excited states explicit and implicit solvent models hydrodesulfurization hydrogen bond molecular charge distribution nitro molecule nitromethane optoelectronic and photovoltaic properties optoelectronic properties