Quantum Chemical Design of D–π–A‐Type Donor Materials for Highly Efficient, Photostable, and Vacuum‐Processed Organic Solar Cells

Abstract

Fullerene‐free donor materials are receiving more and more attention from the scientific community due to their high power conversion efficiencies (PCEs) and large visible‐light‐harvesting capabilities. Herein, five new molecules (ZDM1–ZMD5) with D–π–A‐type skeletons are efficiently designed and theoretically characterized. These newly tailored molecules can improve the PCEs of vacuum‐processed organic solar cells (OSCs). End‐capped donor modifications of DTDCPTT‐2CN (R) are done with well‐organized end‐capped donor units. Density functional theory at MPW1PW91 method along with 6‐31 G(d,p) level is utilized to calculate various photovoltaic (PV), physiochemical, and optoelectronic properties of these novel theoretically planned molecules. Different geometric parameters are also computed for the studied molecules. A narrow bandgap (E g = 1.52–1.93 eV) with redshifting (λ max = 589–614 nm) in the absorption spectrum is observed for ZDM1–ZDM5. Further, low excitation (E x) and binding energies (E b) offer high current charge density (J sc) along with good PCE. A blend study of ZDM3/PC61BM is also carried out to explore the charge transfer behavior of the designed molecules. Finally, more than 10% PCE is predicted (theoretically) using the Scharber model. To sum up, results of different analyses suggest that these theoretically modeled molecules are efficient aspirants for highly stable and efficient vacuum‐processed OSCs.