A series of copolymers PC8DTBT-x (x denotes the content of brominated units) were achieved by varying the amount of the brominated carbazole. The chemical structures, electrochemical properties, optical properties and photovoltaic performance of these copolymers were well characterized. The bromide side chains don’t influent the frontier orbital levels of the conjugated polymers. The absorption coefficiency and fluorescence spectra of copolymers can be changed by the content of bromide units. Higher open circuit voltage and higher fill factor were observed in the organic solar cells using bromide-unit containing copolymers as the donor materials. When the content of bromide units reached 30%, higher absorption coefficiency and higher power conversion efficiency were achieved.

•Chlorine-bearing conjugated polymers exhibit unique properties.•Revealing the structure-property relationship of chlorine-bearing polymers.•Efficient deep-red electroluminescent materials.Since the large steric hindrance caused by chlorine atoms not only suppresses the aggregation but also results in large stokes shift and low self-absorption, a series of donor-acceptor alternating copolymers based on 6,7-dichloroquinoxaline have been synthesized by modifying the structures of oligothiophenes. All the polymers have been well characterized to study the effects of the length of oligothiophenes and the steric hindrance on the optical, electronic and electroluminescent properties. It was observed that the intramolecular charge transfer absorption was weakened by steric hindrance. Unlike non-chloride analogues, prolonged conjugated length resulted in smaller bandgap, given similar steric hindrance. Deep-red emission centered at 678 nm with brightness about 1800 cd m−2 was achieved with external quantum efficiency 1.34% using dopant/host technic.Download high-res image (291KB)Download full-size image

•3,4-Triphenylamine-silole was incorporated into the fluorene-carbazole backbone.•Highly efficient green-emitting materials were designed and synthesized.•Green PLEDs with high efficiency and brightness were obtained.Triphenylamine-containing silole was copolymerized with fluorene and carbazole by Suzuki coupling reactions to obtain a series of copolymers. The chemical structures, electrochemical properties, and optoelectronic properties including absorption, photoluminescence, and electroluminescence of these copolymers were well characterized. The highest absolute photoluminescence quantum efficiency of these polymers in films was up to 81%. 1,3,5-Tri(N-phenylbenzimidizol-2-yl)benzene hole blocking layer greatly boosts the external quantum efficiency up to 4.3% from 0.06%. The external quantum efficiency was further raised to 5.4% by blending copolymer with 2-(4-biphenylyl)-5-phenyl-1,3,4-oxadiazole (PBD), and the largest luminous efficiency as high as 13.6 cd/A was realized at the same time.

•A novel organic–inorganic hybrid emulsion was used as the binder of the waterborne intumescent fire retardant coating and greatly improved the fire resistance performance.•Epoxy resin in emulsion improved the adhesion of the film to substrates (from 2 grade to 0 grade).•Montmorillonite in emulsion greatly improved water resistance, yellowing resistance and fire resistance performance.The core–shell organic-modified montmorillonite (OMMT)/epoxy resin/styrene-acrylic emulsion was prepared using semi-continuous seeded emulsion polymerization and used as the binder of the waterborne intumescent fire retardant coating to improve the fire resistance performance and other basic performance such as water resistance performance, anti-yellowing and adhesion to substrates. Observation with transmission electron microscopy showed that core–shell emulsion had been synthesized successfully. The small angle X-ray diffraction results showed that OMMT was exfoliated and dispersed well in the emulsion within the appropriate content. Fire resistance test, thermal analysis, scanning electron microscopy (SEM), water resistance and yellowing resistance test respectively demonstrated that OMMT greatly improve fire resistance, thermal stability, water resistance and yellowing resistance performance with the addition of in the range of 1.5–2.5 wt.%. Moreover, the core–shell styrene-acrylic emulsion with 5 wt.% epoxy resin (E-44) improve the adhesion of the film to plywood (from 2 grade to 0 grade).

A series of conjugated copolymers consisting of 9,9-dioctylfluorene units and 1,1-bis(4′-N,N-dimethylaniline)-tetraphenylsilole units (APh-TPS) were designed and synthesized by a palladium-catalyzed Suzuki coupling reaction. The chemical structures, electrochemical properties and optoelectronic properties, including the absorption, photoluminescence and electroluminescence (EL), of these copolymers were successfully characterized. EL devices were fabricated in three different configurations: indium tin oxide (ITO)/ poly-(3,4-ethylenedioxythiophene): poly(styrenesulfonic acid; PEDOT:PSS) (50 nm)/polyfluorene (PF)-APh-TPS (80 nm)/Al (device A), ITO/PEDOT:PSS (50 nm)/PF-APh-TPS (80 nm)/Ba/Al (device B) and ITO/PEDOT:PSS (50 nm)/PF-APh-TPS (80 nm)/1,3,5-tris (2-N-phenylbenzimidazolyl) benzene (TPBI) (30 nm)/Ba/Al (device C). The EL properties of PF-APh-TPS were clearly improved compared with those of previously reported silole-containing PFs because of the introduction of N,N-dimethylaniline. The insertion of a TPBI hole-blocking layer not only elevated the luminous and external quantum efficiencies but also improved the color purity by separating the light-emitting layer from the cathode.

High selectivity and yield of aryl–aryl coupling reactions between chlorine-containing aromatic bromides and organotin reagents are reported. The variable reaction selectivity between bromine and chlorine mainly depends on the electronic effects of the aromatic substrates. The reactivity of chlorine can be completely restrained by employing the optimized palladium catalysts, which can be used for the preparation of chlorine-bearing molecules. Then, a series of high molecular weight conjugated copolymers with chlorine on the backbones are straightforwardly synthesized by the Stille condensation reaction. The chlorine-bearing polymers exhibit much lower LUMO, larger Stokes shift and less self-absorption compared with the non-chlorine analogues because of the electron affinity and the large steric hindrance of chlorine atoms. Efficient NIR emission centred at about 758 nm can be obtained based on the single layer system.

Great advances in the subfield of non-fullerene acceptors have been achieved in the last few years. Perylene diimides are among the most investigated due to their excellent electron mobility, high electron affinity and feasible chemical modification. In this review, we summarize reports of small molecule acceptors based on perylene diimides in recent years and highlight the effect of molecular structure on their performance in bulk heterojunction organic solar cells with the hope of providing criteria for designing acceptors based on perylene diimides.

High selectivity and yield of aryl–aryl coupling reactions between chlorine-containing aromatic bromides and organotin reagents are reported. The variable reaction selectivity between bromine and chlorine mainly depends on the electronic effects of the aromatic substrates. The reactivity of chlorine can be completely restrained by employing the optimized palladium catalysts, which can be used for the preparation of chlorine-bearing molecules. Then, a series of high molecular weight conjugated copolymers with chlorine on the backbones are straightforwardly synthesized by the Stille condensation reaction. The chlorine-bearing polymers exhibit much lower LUMO, larger Stokes shift and less self-absorption compared with the non-chlorine analogues because of the electron affinity and the large steric hindrance of chlorine atoms. Efficient NIR emission centred at about 758 nm can be obtained based on the single layer system.