Enhancing the photovoltaic properties of phenylsulfonyl carbazole-based materials by incorporating a thiophene ring and end-capped acceptors for organic solar cells: a DFT approach

In the present study, phenylsulfonyl carbazole-based organic chromophores, abbreviated as PSCD1-PSCD6, were designed through tailoring the terminal group of a PSCR chromophore. Quantum chemical studies were carried out using the M06/6-311G(d,p) functional to understand the electronic, structural, chemical, and optical properties of the title chromophores. All the derivatives exhibited reduced band gaps with Delta E = 2.742-3.025 eV and significant bathochromic shifts with lambda max = 496.891-545.009 nm compared with PSCR. DOS and TDM investigations revealed that the central acceptor moiety plays a crucial role in charge transfer. The minimal binding energy values for PSCD1-PSCD6 indicated a greater rate of exciton dissociation and more effective charge transfer than PSCR. The studied compounds exhibited open-circuit voltages (Voc) ranging from 1.015 to 1.720 V. PSCD4 showed a significantly reduced band gap of 2.742 eV and a red-shifted absorption maximum of 545.009 nm, among all the studied chromophores. These findings suggest that all the designed organic chromophores might be utilized as reasonable photovoltaic materials.