Redox Switching in Ethenyl‐Bridged Bisphospholes

A 2e^?/2H⁺ redox platform has been implemented in the ethenyl‐bridged bisphosphol‐3‐ol 1 to afford the first phospholes that feature chemically reversible oxidations. Oxidation of the title compounds to the corresponding bisphosphol‐3‐one 2 leads to a change in conjugation topology and a concomitant hypsochromic shift of the lowest‐energy absorption maximum by 100 nm. Electrochemical oxidation proceeds without any detectable intermediates, whereas the deprotonated form of 1 can be observed in an aprotic medium during the reduction of 2 . This dianionic intermediate 3 is characterized by end absorptions that are bathochromically shifted by circa 200 nm compared to those of 2 .     

纳米TiO2膜负载聚(3-溴噻吩)的电化学聚合和电色效应研究

本文以纳米多孔的TiO2膜为基底,通过恒电流阳极聚合的方法制备聚(3-溴噻吩) (PBrT)膜,并研究负载在纳米TiO2膜上PBrT的电致变色性能。采用原子力显微镜(AFM)对纳米TiO2膜的形貌进行表征。利用紫外吸收光谱、计时安培法、计时吸收法研究PBrT膜的电致变色性能。结果显示,沉积在纳米多孔TiO2膜上的PBrT具有更优越的电致变色性能。PBrT膜氧化态时为亮红色,还原态时为深蓝色,颜色的对比度为22%,库仑效率为70%,着色效率为191.3 cm2 C-1（还原态）,88.9 cm2 C-1（氧化态）,该聚合膜具有良好的记忆效应。PBrT/TiO2优异的电致变色性能使其成为良好的电致变色材料,在电致变色器件方面具有潜在的应用价值。     

Cerium-Modified Mesoporous Antimony Doped Tin Oxide as Intercalation-Free Charge Storage Layers for Electrochromic Devices

Charge storage layers are an important component of electrochromic devices, which are expected to exhibit high storage capacity and transparency as well as fast electron transfer rates. However, these layers often rely on the (de)intercalation of ions into the crystal lattice of the material and therefore require optimization to be compatible with non-intercalating electrolytes. In this report, the post-modification of mesoporous antimony-doped tin oxide (ATO) nanoparticle layers with a redox-active cerium compound is described. In particular, the switching of the Ce³⁺/Ce⁴⁺ couple on the conductive nanoparticle scaffold is demonstrated using tetrabutylammonium perchlorate as a non-intercalating electrolyte. Remarkably, high storage capacities of up to 27 mC cm⁻² and transmittance values of ≈90% are achieved. Variation of the antimony doping concentration revealed that nanoparticle layers doped with 15% Sb exhibit the highest capacity, which can be attributed to increased conductivity in the potential range where the Ce³⁺ ions are oxidized. Finally, the cerium-modified ATO films show promising performance as charge storage layers in an electrochromic device with a viologen-anchored ATO layer as the electrochromic working electrode. Switching times of ≈0.4 s highlight the fast electron transfer capability of the cerium-decorated ATO layer, even when a non-intercalating electrolyte is used.     

A new black to highly transmissive switching bilayer polymer composite films with electroactive pEA as a color buffer layer for improving electrochromic stability

Two reported D-A-D monomers based on 3,4-ethylenedioxythiophene (EDOT) were selected for electrochemical copolymerization to obtain copolymer film, named pRG. Then, a soluble polymer poly[3,4-ethylenedioxythiophene-alt-3,4-bis([2-ethylhexyl]oxy)thiophene] (pEA) based on the EDOT derivative was screened out, which is complementary to the absorption trough of the pRG film in visible region and matched with its working potential. The bilayer composite film pRG/pEA was obtained by spinning pEA basement membrane on fluorine doped tin oxide (FTO) coated glass surface, and then in situ electrochemical polymerization of pRG film. Compared to the pRG monolayer film, the bilayer composite film shows a more saturated black color in the neutral state and significant improvement on cyclic stability (only decreased by 1.7% after 250 cycles, while pRG film decreased by 17.1%). The introduction of pEA buffer layer not only achieves the full spectral absorption of the composite film in the visible region, but also significantly improves the cyclic stability of the bilayer composite film. The assembled EC prototype device based on the pRG/pEA composite film exhibits a “black to high transmission” reversible switch. Finally, this method combining electrochemical copolymerization, spin-coating, lamination and other methods provides a new research idea for designing and preparing black to transmissive electrochromic materials.