Synthesis and Photovoltaic Investigation of 8,10-Bis(2-octyldodecyl)-8,10-dihydro-9H-bisthieno[2′,3′:7,8;3″,2″:5,6] naphtho[2,3-d]imidazol-9-one Based Conjugated Polymers Using a Nonfullerene Acceptor

Abstract

Two donor–acceptor (D–A) conjugated polymers designed on same 8,10-bis­(2-octyldodecyl)-8,10-dihydro-9H-bisthieno­[2′,3′:7,8;3″,2″:5,6]­naphtho­[2,3- d]­imidazole-9-one donor and dissimilar acceptor units, i.e., benzothiadiazole (P104) and fluorinated benzothiadiazole (P105), were synthesized, and their photophysical and electrochemical properties were investigated. The influence of the incorporation of fluorine atoms into the benzothiadiazole (BT) acceptor moiety in the polymer backbone on the photovoltaic performance when combined with the low bandgap nonfullerene acceptor ITIC-F was explored. The polymer solar cells based on P105:ITIC-F exhibited higher PCE (10.65%) as compared to P104:ITIC-F (8.32%), resulting from the improved values of all the photovoltaic parameters. A high value of V oc is linked with the deeper highest occupied molecular orbital energy level of P105, and the larger values of both short circuit current and fill factor are endorsed to the efficient exciton separation into charge carriers, their subsequent transfer owing to the increased value of dielectric constant and reduced value of exciton dissociation and energy loss, and promoted balanced charge transportation. The intra/interchain interaction can be modulated by F atom substitution in the BT unit, resulting reduction in π–π stacking distance, and increase in the crystal coherence length, benefiting the charge transportation in the active layer. These results offer a simple effective approach to regulate the optical and electrochemical properties and therefore increase the overall photovoltaic response.

Efficient Exciton Diffusion in Micrometer-Sized Domains of Nanographene-Based Nonfullerene Acceptors with Long Exciton Lifetimes in Blend Films with Conjugated Polymer

“…The ratios of J ph / J sat under short-circuit conditions and at the maximal power points can be used to estimate η dis and η col of the devices (Table ). , The η dis values of all TACIC-based devices were comparable (0.93–0.95), suggesting that the alkyl chain lengths at the thienoazacoronene unit have little impact on the efficiency of the charge dissociation from the charge-separated state at the D–A interface. Meanwhile, the values of η col were determined as follows: 0.77 PBDB-T:TACIC-BO > 0.71 PBDB-T:TACIC-HD > 0.67 PBDB-T:TACIC-EH, which justify the order of J SC and FF of the OPV devices.…”

Dithieno[2,3‐e:3′,2′‐g]isoindole‐7,9(8H)‐Dione and Dithieno[3′,2′:5,6;2″,3″:7,8]naphtho[2,3‐d]imidazol‐9(10H)‐One‐Based Wide Bandgap Copolymer for Efficient Polymer Solar Cells

“…In Scheme 1 , the synthesis process to design the copolymers P133 and P135 is shown. The monomers 4,8‐Bis (5‐(2‐ethylhexyl) thiophen‐2‐yl) benzo [1,2‐b:4,5‐b'] thiophene‐2,6 diyl) bis (trilstmethyannane) M1, [ 40 ] 2,5‐dibromo‐8,10‐bis (2‐octyldodecyl) −8 H‐thieno [3′,2′:5.6;2″,3″:7.8] naphtho [2,3‐d] imidazole‐9 (10 H) ‐one M2, [ 41 ] and 2,5‐Dibromo‐8‐(2‐octyldodecyl)−7 H‐dithieno [2,3‐e:3′, 2′‐g] isoindole‐7, 9 (8H)‐dione M3 [ 42 ] were synthesized as reported in the literature. The P133 and P135 were prepared by conventional Stille cross‐coupling polymerization among M1 and M2 , or M3 , respectively, in the presence of a palladium catalyst Pd (Ph 3 P) 4 in boiling toluene for 48 h in a stream of argon.…”

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 Nonfullerene Polymer Solar Cells

“…Synthesis of 8,10‐dihydro‐9 H ‐bistieno [2′, 3′: 7.8; 3″, 2″:5.6] naphtho [2,3‐d] imidazol‐9‐one‐based copolymers poly{2,10‐(8,10‐dihydro‐9H‐bisthieno[2′,3′:7.8;3″,2″:5.6]naphtho[2,3‐d]imidazol‐9‐one)‐alt‐2,5‐(2‐dodecylbenzo[1,2‐b:3,4‐b′:6,5‐b″]trithiophene)} [ PDTNIA‐3TB (P1) ], poly{2,10‐(8,10 ‐dihydro‐9H‐bisthieno[2′,3′:7.8;3″,2″:5.6]naphtho[2,3‐d]imidazol‐9‐one)‐alt‐2,9‐(5,6‐dioctylnaphtho[2,1‐b:3,4‐b′]dithiophene)} [ PDTNIA‐DTN (P2) ], poly{2,10‐(8,10 ‐dihydro‐9H‐bisthieno[2′,3′:7.8;3″,2″:5.6]naphtho[2,3‐d]imidazol‐9‐one)‐alt‐2,7‐(4,5‐diundecylbenzo[2,1‐b:3,4‐b′]dithiophene)} [ PDTNIA‐DTB (P3)], and the acceptor comonomer M1 is shown in Scheme 1 . Comonomers of 2,5‐dibromo‐8,10‐bis (2‐octyldodecyl)−8,10‐dihydro‐9 H ‐bistieno [2′, 3′: 7, 8; 3″, 2″: 5,6] naphtho [2,3‐d] imidazol‐9‐one (M1), [ 58 ] 3TB, [ 59 ] DTN, [ 60 ] and DTB [ 61 ] were prepared according to previously described methods. By copolymerization of the acceptor monomer M1 with various donor comonomers under the conditions of the Style cross‐coupling reaction in the presence of a palladium catalyst, new D–A conjugated copolymers (PDTNIA‐3 TB) ( P1 ), (PDTNIA‐DTN) ( P2 ), and (PDTNIA‐DTB) ( P3 ) were obtained (Scheme 1).…”