A multi stimuli responsive material with rhodamine B and carbazole groups

A facile material with multi stimuli responsive behaviors was developed. The chromic properties of the material can be observed by stimulating it with light, electricity and ions.

The first thieno[3,4-b]pyrazine based small molecular acceptor with a linear A2–A1–D–A1–A2 skeleton for fullerene-free organic solar cells with a high Voc of 1.05 V

The first thieno[3,4-b]pyrazine (TP) based non-fullerene acceptor was designed and synthesized, which could realize a moderate power conversion efficiency (PCE) of 5.81% with a high open-circuit voltage (V_oc) of 1.05 V by using J61 as a donor polymer.

Wide Band Gap and Highly Conjugated Copolymers Incorporating 2-(Triisopropylsilylethynyl)thiophene-Substituted Benzodithiophene for Efficient Non-Fullerene Organic Solar Cells

Recent years have seen a rapid progress in the power conversion efficiencies (PCEs) of non-fullerene polymer solar cells (NF PSCs). However, the donor materials accordingly used are typical low or medium band gap polymers, some of which possess badly overlapped absorption spectra relative to the low band gap n-type acceptors, for example, 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)indanone)-5,5,11,11-tetrakis(4-hexylphenyl)dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene) (ITIC). To obtain polymers simultaneously owning a wide band gap, a highly extended π-conjugation system, and a low-lying highest occupied molecular orbital (HOMO), a polymer (PBDTSi-TA) incorporating 2-(triisopropylsilylethynyl)thiophene substituted benzodithiophene (BDTSi) and fluorinated benzotriazole (FTAZ) units was designed and synthesized. PBDTSi-TA (E_g^opt = 1.92 eV) exhibits strong molecular aggregation properties and a lower-lying HOMO energy level compared to its structural analogues. When blended with ITIC and after device optimization with solvent vapor annealing in combination with a developed PDIN/BCP/Ag cathode structure, PSCs yielded a PCE of 7.51%, with V_oc = 0.96 V. Moreover, a rather small energy loss (E_loss) of 0.6-0.63 eV was determined. For comparison, another polymer (PBDTSi-Qx) with a more-electron-deficient quinoxaline-based acceptor unit was also synthesized and applied to NF PSCs. Charge generation rate, exciton dissociation probabilities, dark leakage current, nanoscale morphology, and charge carrier mobilities have been evaluated to probe the reasons for the differentiated performances. The results suggest that PBDTSi-TA is a promising donor material for NF PSCs, and the molecular design strategy demonstrated here would be helpful for pursuing high-performance polymers for PSCs.

Recent Advances in Wide-Bandgap Photovoltaic Polymers

The past decade has witnessed significant advances in the field of organic solar cells (OSCs). Ongoing improvements in the power conversion efficiency of OSCs have been achieved, which were mainly attributed to the design and synthesis of novel conjugated polymers with different architectures and functional moieties. Among various conjugated polymers, the development of wide-bandgap (WBG) polymers has received less attention than that of low-bandgap and medium-bandgap polymers. Here, we briefly summarize recent advances in WBG polymers and their applications in organic photovoltaic (PV) devices, such as tandem, ternary, and non-fullerene solar cells. Addtionally, we also dissuss the application of high open-circuit voltage tandem solar cells in PV-driven electrochemical water dissociation. We mainly focus on the molecular design strategies, the structure-property correlations, and the photovoltaic performance of these WBG polymers. Finally, we extract empirical regularities and provide invigorating perspectives on the future development of WBG photovoltaic materials.

A novel donor–acceptor alternating copolymer based on angular-shaped benzo[2,1-b:3,4-b′]diselenophene for bulk heterojunction solar cells

A new D–A copolymer PBDSe-DTBT, based on the angular-shaped benzo[2,1-b:3,4-b′]dithiophene (BDP) unit with a selenium substitution, having both a low optical band gap of 1.71 eV and a deep HOMO level of −5.37 eV, has offered a promising average BHJ device efficiency of 5.6%.

Donor–acceptor copolymers containing the phthalazinone–thiophene structure synthesized by classical nucleophilic aromatic polymerization

The unique monomer containing thiophene and phthalazinone groups could make these “non-ether bond poly(aryl ethers)s” change into photoelectric polymers.

Investigating the crystalline nature, charge transport properties and photovoltaic performances of ladder-type donor based small molecules

The indacenodithieno[3,2-b]thiophene (IDTT) core promoted the crystallinity of ladder-type donor based small molecules and π-bridge structures could improve the photovoltaic performance.