New High Bandgap 8,10‐Dihydro‐9H‐Bistieno[2',3':7.8;3“,2”:5.6]Naphtho[2,3‐d] Imidazole‐9‐One Based Donor‐Acceptor Copolymers for Non‐fullerene Polymer Solar Cellsстатья
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Дата последнего поиска статьи во внешних источниках: 24 сентября 2020 г.
Аннотация:Three D–A conjugated copolymers based on the same 8,10-dihydro-9H-bisthieno[20,30:7.8;300,200:5.6]naphtho[2,3-d]imidazol-9-one (DTNIA) acceptorunit and different donor units, i.e., 2-dodecylbenzo[1,2-b:3,4-b0:6,5-b00]trithio-phene (3TB) (P1), 5,6-dioctylnaphtho[2,1-b:3,4-b0]dithiophene (DTN) (P2), and4,5-diundecylbenzo[2,1-b:3,4-b0]dithiophene (DTB) (P3), are formulated andsynthesized. All the copolymers exhibit deep highest occupied molecular energylevels of5.43,5.50, and5.51 eV for P1, P2, and P3, respectively, and showan optical bandgap of 2.18, 2.12, and 2.11 eV, for P1, P2, and P3, respectively.These copolymers are used as donors for the construction of polymer solar cellscombining ITIC-m as an electron acceptor. The optimized polymer solar cellsbased on P1:ITIC-m, P2:ITIC-m, and P3:ITIC-m realize overall power conversionefficiency of9.62%, 12.84%, and 11.80%, respectively. The greater value ofopen circuit voltage for P2 and P3 relative to P1 may be due to the deeper highestoccupied molecular orbital energy level of P2 and P3 as compared to P1. Thehighest power conversion efficiency for the P2-based polymer solar cells may beoriginated from the denserπ–πstacking distance and relatively improvedcrystallinity, which are advantageous for balanced charge transport, resulting in acomparatively highfill factor and short circuit current.