Donor‐π‐Acceptor N‐Methyl‐4,5‐Diazacarbazole Based Ultra‐High Performance Organic Solar Cells: A Density Functional Theory Study

Herein, a series of D‐π‐A conjugated molecules based on donor N ‐methyl‐4,5‐diazacarbazole with a variety of acceptor end caps are quantum chemically proposed with aim of rational design of novel organic materials applicable in organic solar cells (OSCs) by using ab initio density functional theory (DFT) calculations. Herein, the optoelectronic performance of tailored molecules was explored by substituting the bay annulated indigo dye acceptor unit with a variety of molecules including 4‐(5‐methyl‐thiophene‐2‐yl)benzothiadiazole; 1 , 2‐(3‐methyl‐5‐methylene‐4‐oxothiazolidin‐2‐ylidene)‐malononitrile; 2 , 3‐methyl‐5‐methylene‐2‐thioxothiazolodin‐4‐one; 3 , 2‐methylenemalononitrile; 4 , 2‐cynaoacryli‐caidmethylester; 5 , those are linked through the thiophene bridge. The DFT results encompassed the significant variations of electronic behavior of newly designed molecules (M1‐M5) with respect to the reference molecule, especially in the case of 1 , 2, and 3 substitution. The designed molecules exhibit excellent electron transition due to the increasing λ max toward the higher region. The outcomes of this study proposed the designed molecules as a possible choice in designing efficient optoelectronic materials for OSCs. From the future point of view, this finding suggests that the pre‐synthesis of such hypothetical molecules using quantum mechanics is an effective strategy for designing ideal candidates for solar cell applications.