Effect of thiophene, 3-hexylthiophene, selenophene, and Thieno[3,2-b]thiophene spacers on OPV device performance of novel 2,1,3-benzothiadiazole based alternating copolymers

Design Principles for the Acceptor Units in Donor–Acceptor Conjugated Polymers

“…Theoretical calculations were performed by using Gaussian09 (A02 software package) . Density functional theory (DFT) methods were applied for the tetramers, in the form of (D–B–A–B) 4 (D, donor; A, acceptor; B, bridge) at B3LYP hybrid functional with 6-311g­(d) basis set with tight SCF convergence criteria which have presented successful results in previous studies. − Geometry optimizations were started from different initial conformations such as the relative conformation of donor and acceptor by controlling the torsional angle between connected donor, acceptor, and bridge units, as shown in Figure S1 systemically to determine the lowest energy geometries. Electrostatic potential surface (ESP), highest occupied molecular orbitals (HOMO), and lowest unoccupied molecular orbitals (LUMO) were calculated for the optimized geometries of tetramers.…”

Exploring the Optoelectronic Properties of D-A and A-D-A 2,2′-bi[3,2-b]thienothiophene Derivatives

“…Thus, they were employed for the fabrication of efficient dye-sensitized solar cells (DSSCs) [ 19 , 20 , 21 , 22 ] or classical organic solar cells (OSCs). In the latter, they were successfully used as building blocks in donor molecules [ 23 , 24 , 25 , 26 , 27 , 28 ], as non-fullerene acceptors [ 29 , 30 , 31 , 32 , 33 , 34 ] or were incorporated in monomers that, upon (co)polymerization reactions, lead to macromolecular products used as active materials in OSCs fabrication [ 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. Moreover, it was reported that replacing a thiophene ring or a bithiophene unit either in acceptors ( A ) (e.g., [ 29 ]) or in donors ( D ) (e.g., [ 24 ]) with a [3,2- b ]-TT moiety indicated an improvement in the efficiency of the OSCs exhibiting the modified donors and/or acceptors.…”