We reported a chlorinated polymer donor PBT4T-Cl that showed a high PCE of 11.18%. The results demonstrated chlorination of the thiophene moiety could finetune the HOMO level of the corresponding polymer as well as the carrier mobility and morphologies of the blend film, eventually improving its photovoltaic properties as a donor without thermal annealing.

Chlorinated benzothiadiazole-based polymers with multiple chlorine atoms were designed and synthesized for polymer solar cells to achieve enhanced open-circuit voltage and improved power conversion efficiency. Chlorine substitution was found to affect molecular orientation, increase crystallinity, and thereby alter band gap and charge transport properties. The one-chlorine-substituted PCBT4T-2OD exhibited a larger portion of "face-on" orientation than that of other two polymers, nonchlorinated PBT4T-2OD and two-chlorine-substituted PCCBT4T-2OD, in the polymer:PC 71 BM blended films. PCBT4T-2OD also showed the largest crystallite sizes in those three polymers. The improved molecular orientation and larger crystallite sizes would definitely facilitate the charge transport in the active layer and enhance the performance of corresponding polymer solar cells. The highest power conversion efficiency of 8.21% with PC 71 BM was achieved in the photovoltaic device of PCBT4T-2OD. It is approximately 68% higher than that of the nonchlorine analog.

In this work, novel core‐shell structured Fe3Si@C/SiC/Fe3O4/SiO2 nanoparticles were fabricated via a polymer‐derived ceramic approach, starting from sol‐like polycarbosilane‐encapsulated polynuclear carbonyl iron nanoparticles and with pitch as an isolator to avoid aggregation during polymer‐to‐ceramic transformation. Elemental analysis, X‐ray photoelectron spectroscopy, X‐ray diffraction, transmission electron microscope, vibrating sample magnetometer and vector network analyzer were employed to investigate the composition, nano/microstructure, morphology, and dielectric/magnetic properties. The results show that the size of obtained Fe3Si@C/SiC/Fe3O4/SiO2 nanoparticles is in the range of 2‐200 nm. And the unique core‐shell structure with the hetero‐interface combined with simultaneous dielectric and magnetic loss endow Fe3Si@C/SiC/Fe3O4/SiO2 nanoparticles outstanding electromagnetic (EM) wave absorbing performance. With a sample thickness of 4.5 mm, the minimum reflection coefficient (RC) of the composites Fe3Si@C/SiC/Fe3O4/SiO2 mixed with paraffin wax reaches −44.7 dB, indicating that more than 99.99% EM waves can be attenuated by the composites. By adjusting the sample thicknesses, the effective bandwidth (the bandwidth of RC values lower than −10 dB) amounts 9.5 GHz (from 2.5 to 12.0 GHz), covering the whole C and X bands.