Exploring organic semiconductors in solution: the effects of solvation, alkylization, and doping

The first-principles simulation of the electronic structure organic semiconductors in solution poses a number challenges that are not trivial to address simultaneously. In this work, we investigate effects and mutual interplay solvation, alkylization, doping on structural, electronic, optical properties sexithiophene, representative semiconductor molecule. To end, employ (time-dependent) density functional theory conjunction with polarizable-continuum model. We find torsion between adjacent monomer units plays key role, as it strongly influences molecule, including energy gap, ionization potential, band widths. Alkylization promotes delocalization molecular orbitals up first methyl unit, regardless chain length, leading an overall shift levels. alterations reflected absorption, which is additionally affected by dynamical solute-solvent interactions. Taking all these into account, solvents decrease gap amount depends its polarity, concomitantly increase oscillator strength excitation. interaction dopant molecule planarization. such scenario, solvation alkylization enhance charge transfer both ground state excited state.