P3HT-Based Photovoltaic Cells with a High V_oc of 1.22 V by Using a Benzotriazole-Containing Nonfullerene Acceptor End-Capped with Thiazolidine-2,4-dione

Abstract

A novel A 2 −A 1 −D−A 1 −A 2 -type nonfullerene acceptor, using thiazolidine-2,4-dione (TD) as the terminal acceptor (A 2 ) for the first time, was designed and synthesized. The final molecule, BTA2, shows a high-lying lowest unoccupied molecular orbital (LUMO) of −3.38 eV and a wide optical band gap of 2.00 eV. Fullerene-free organic solar cells based on P3HT:BTA2 realized a high open-circuit voltage (V oc ) of 1.22 V with a power conversion efficiency (PCE) of 4.50%. These values are significantly higher than those of the PC 61 BM-based control device (V oc = 0.61 V, PCE = 3.67%), which indicates the feasibility of thiazolidine-2,4-dione to construct nonfullerene small-molecule acceptors with high V oc and PCE.

Wide Band Gap Non‐Fullerene Small Molecular Acceptors Containing Spirobifluorene and Benzotriazole with Three Different End‐Capped Groups for P3HT‐Based Organic Solar Cells

“…Many researches have proved that SMAs with twisted three-dimensional (3D) or quasi-3D structures are benefit to tune the blend morphology. [45,46] Therefore, SF and BTA are potential bulding blocks for constructing effective SMAs for OPV applications. [31][32][33][34][35][36] There are many electron-deficient units connected with the central SF unit to construct non-fullerene SMAs, such as benzothiadiazole (BT), [37,38] diketopyrrolopyrrole (DPP), [39][40][41] and perylene diimide (PDI).…”

Controlling the Cyano‐Containing A2 Segments in A2‐A1‐D‐A1‐A2 Type Non‐Fullerene Acceptors to Combine with a Benzotriazole‐Based p‐Type Polymer: “Same‐Acceptor‐Strategy” for High VOC Organic Solar Cells

“…We had devoted much efforts to develop a series of benzotriazole (BTA) based SMAs with A 2 ‐A 1 ‐D‐A 1 ‐A 2 skeleton, which provide a feasible model to investigate the effect of end‐capped group of A 2 . We found that the introduction of dicyanomethylene group into the terminal rhodanine segment could dramatically enhance the PCE when paired with different p‐type polymer .…”

Pyran‐Bridged Indacenodithiophene as a Building Block for Constructing Efficient A–D–A‐Type Nonfullerene Acceptors for Polymer Solar Cells

“…The end groups have a significant effect on the lowest unoccupied molecular orbital (LUMO) levels and molecular packing behaviors. These nonfullerene acceptors were usually end‐capped with dicyanomethylene‐3‐indanone (IC), fluorinated IC, methylated IC, thienyl‐fused indanone, or rhodamine . Hou and co‐workers reported the acceptor ITCC, with thienyl‐fused indanone as end groups .…”

“…The side chains, which have included hexylphenyl, hexylthienyl, hexylselenophenyl, and alkyl groups, are also essential components of nonfullerene acceptors, which guarantee solubility, modulate aggregation behaviors, and adjust energy levels. π‐Bridges, such as benzothiazole, thiophene, diketopyrrolopyrrole, thiazole, were usually incorporated to elongate the π‐conjugation. Since these nonfullerene acceptors have excellent flexibility of structure modification and great potential to achieve high efficiency, there is much scope to investigations to optimize their chemical structures.…”

“…These nonfullerenea cceptors were usually end-capped with dicyanomethylene-3-indanone (IC), [19,23,24] fluorinated IC, [9,25] methylatedI C, [26] thienyl-fused indanone, [17,27] or rhodamine. [14,28] Hou and co-workersr eported the acceptorI TCC, with thienyl-fused indanone as end groups. [17] This molecule gave rise to ah igherL UMO level, closer p-p stacking, and highere lectron mobility than ITIC.…”