Non-fullerene small molecular acceptors with a carbazole core for organic solar cells with high open-circuit voltage

Karapala

et al. 2021

J Chinese Chemical Soc

In this review, the properties, performance, advantages, and applications of carbazole-based nonfullerene acceptors (NFAs) are summarized and categorized by fused-ring number. The recent advances of carbazole-based NFAs are depicted with their decent photovoltaic performance, enabled by the versatality of elegant molecular design. These literature precedents sufficiently validate that carbazole can be exploited as a promising building block embedded in functional, high-performance NFAs. The structure-to-performance relation of carbazole-based NFAs is systematically studied, which is believed to facilitate the development of photovoltaic technology.

Section: Photovoltaic Performancementioning

confidence: 99%

Recent advances of carbazole‐based nonfullerene acceptors: Molecular design, optoelectronic properties, and photovoltaic performance in organic solar cells

Karapala

et al. 2021

J Chinese Chemical Soc

“…Inspired by these encouraging results, rational structural modifications have been conducted on FBR subsequently. For example, by replacing the fluorene core in the FBR with carbazole moiety, Ma and coworkers [62] synthesized two new RD-based NFAs, CzC6C8 and CzC8 (Scheme 2, Table 1), with branched and linear alkyl side chains, respectively. It was demonstrated that CzC8 with a linear n-octyl chain exhibited a more closely molecular stacking and a more preferred film morphology than CzC6C8 with a branched 2-hexyldecyl chain, leading to a Scheme 2 Chemical structures of NFAs with a tricyclic/tetracyclic electron-rich core.…”

Section: Nfas With a Tricyclic Electron-rich Corementioning

confidence: 99%

Rhodanine-based nonfullerene acceptors for organic solar cells

Liu¹,

Li²,

Zhao

2019

Sci. China Mater.

Significant progress on the development of nonfullerene acceptors (NFAs) for organic solar cells (OSCs) has been made in the past several years, and the power conversion efficiency (PCE) exceeding 17% has been already realized based on a tandem non-fullerene device. To date, NFAs with a linearly fused acceptor-donor-acceptor (A-D-A) structure are of great interest, due to their attracting synthetic flexibility and high photovoltaic performance. Rhodanine is one of the most studied electron-withdrawing moieties to construct such AD A type NFAs, and the resulting single-junction OSCs have produced PCEs of~10%. More interestingly, those rhodanine-based NFAs have demonstrated a particularly excellent compatibility with well-known P3HT donor, enabling respectable PCEs over 7%. Thus in this review, we summarize the important advances on rhodanine-based NFAs with a main focus on discussing the molecular design strategies, providing a better understanding of the structure-property relationship for those rhodanine-based NFAs.

ACS Appl. Mater. Interfaces

“…The optimal device based on J61:BTA3 obtained a V OC of 1.15 V with PCE approaching 8.3% . Bo and coworkers synthesized a novel carbazole-cored n-type material CzC8, coupled with different donor materials based on the BDT unit, and obtained a V OC of 1.16 V accompanying a PCE of 4.91% . Next, in 2019, Zhu and coworkers reported a small molecule acceptor IBR, and the optimal device exhibited a V OC of 1.16 V with a PCE of 6.53% when blended with PBDB-T .…”

Section: Introductionmentioning

confidence: 99%

Tricyclic or Pentacyclic D Units: Design of D−π–A-Type Copolymers for High V_OC Organic Photovoltaic Cells

Dai

Lei

Bao

et al. 2021

Although there are several electron-donating (D) units, only the classic benzo[1,2-b:4,5-b′]dithiophenes (BDT) unit was utilized to develop D−π–A-type copolymers for high-voltage organic photovoltaic (OPV) cells. Hence, in this work, we chose two tricyclic D units, BDT and benzo[1,2-b:4,5-b′]difurans (BDF), together with one pentacyclic ring, dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophenes (DTBDT), to comprehensively study the effect of different D units on the optoelectronic properties and photovoltaic performance. By copolymerized with the benzo[1,2,3]triazole (BTA) electron-accepting unit, the final copolymers J52-Cl, F11, and PE52 were combined with a nonfullerene acceptor (NFA) F-BTA3 according to the “Same-A-Strategy.” As we preconceived, all the three single-junction OPV cells can obtain high open-circuit voltage (V OC) over 1.10 V. Although the tricyclic D unit of BDF exhibits a slightly lower V OC of 1.12 V because of its mildly larger energy loss of 0.698 eV, its higher carrier mobilities and exciton dissociation efficiency strikingly boost the short-circuit current (J SC) and fill factor, which contribute to a comparable PCE of 10.04% with J52-Cl (10.10%). However, the DTBDT-based polymer PE52 shows the worst performance with a PCE of 6.78% and a V OC of 1.14 V, owing to the higher bimolecular recombination and disordered molecular stacking. Our results indicate that tricyclic D units should be a better choice for constructing D−π–A-type polymers for high-voltage photovoltaic materials than the pentacyclic analogues.