Synthesis and photovoltaic performance of novel thiophenyl-methylene-9H-fluorene-based low bandgap polymers

Synthesis and Photovoltaic Characterization of Dithieno[3,2‐b:2′,3′‐d]thiophene‐Derived Narrow‐Bandgap Polymers

“…This revealed that the substituents adjacent to DPP core exerts certain effect on the energy levels of the resulted polymers. The low‐lying LUMO level of PDTT‐TTz indicated TTz as a good acceptor, which agrees well with the reported polymers . The LUMO energy level of the PDTT‐TTz and PDTT‐TPD was about 0.6 eV higher than that of PC 61 BM (−4.0 eV), generating a downhill driving force for the energetically favorable electron transfer reactions.…”

“…Tetrahydrofuran (THF) was dried over sodium/benzophenone and freshly distilled before use. The intermediate compounds including 3,4‐dibromo‐2,5‐diformylthiophene 1 , dithieno[3,2‐b:2′,3′‐d]thiophene‐2,6‐dicarboxylic acid diethyl ester 2 , 2,6‐dibromodithieno[3,2‐b;2’,3’‐d]thiophene M1 , 2,6‐bis[2′‐(3′‐dodecylthienyl)]‐dibromodithieno‐[3,2‐b;2′,3′‐d]thiophene M2 , 3,6‐bis(4‐bromophenyl)pyrrolo[3,4‐c]pyrrole‐1,4‐dione 5 , 3,6‐bis(4‐bromophenyl)‐2,5‐bis(2‐ethylhexyl)pyrrolo[3,4‐c]pyrrole‐1,4(2H,5H)‐dione 6 , 1,4‐diketo‐2,5‐ di(2‐ethylhexyl)pyrrolo[3,4‐c]pyrrole‐3,6‐di‐phenyl‐4‐pinacolato boron ester (PDDP), 2,5‐bis(5‐bromo‐3‐((2‐dodecyl)oxy)thiophen‐2‐yl)thiazolo[5,4‐d]thiazole (TTz‐Br), 1,3‐dibromo‐5‐octylthieno[3,4‐c]pyrrole‐4,6‐dione (TPD‐Br) were prepared according to a slightly modified procedure in literature, with details shown in Supporting Information.…”

“…Considerable progress has been made in this area, and the power conversion efficiencies (PCEs) of solution‐processed polymer solar cells have reached 9–10.6% . Because most of the solar energy is harvested by p‐type polymers, extensive research efforts have been devoted to develop new polymer donors that possess a broad and intense absorption profile across the solar spectrum and large free charge‐carrier mobility for facile charge transport . However, it is still challenging to achieve a semiconducting polymer with a deep HOMO energy level while maintaining enough driving force for electron transfer to fullerenes in BHJ solar cells .…”

Synthesis and Photovoltaic Performance of a [1,2,3]Triazolo[4,5‐g]quinoxaline‐Based Low‐Bandgap Polymer

“…With a bandgap of 1.63 eV, this polymer has wide absorption ranging from 300-760 nm in fi lm. Bulk heterojunction solar cells fabricated by blending PFDTBTzQ-2OC1 with [6,6]-phenyl-C 71 -butyric acid methyl ester exhibit a maximum power conversion effi ciency of 1.31%, with a short-circuit current density of 1.98 mA cm -2 , an open-circuit voltage of 0.74 V, and a fi ll factor of 0.47. as the power conversion effi ciency (PCE) of PSCs has been improved from 1% to over 8%, [8][9][10] with a recent record hitting 9.2%. [ 11 ] However, there are still some key issues that need to be addressed to push PSCs for commercial application which include new materials and device engineering development to push the PCE up to 10%, reliable encapsulation technology to secure long-life workable devices, and robust mass-production processes for device making.…”

“…as the power conversion effi ciency (PCE) of PSCs has been improved from 1% to over 8%, [8][9][10] with a recent record hitting 9.2%. [ 11 ] However, there are still some key issues that need to be addressed to push PSCs for commercial application which include new materials and device engineering development to push the PCE up to 10%, reliable encapsulation technology to secure long-life workable devices, and robust mass-production processes for device making.…”