Azobenzene-dyed, nanofibrous microstructure for improving photothermal effect of polymer gel electrolyte

By using better photo-heatable polymer gel electrolyte of PAN (I−/I3−) with azobenzene-dyed, nanofibrous microstructure, it is found that the photo-isomerizing C11-AZO-C11 dye serves as “micro solar -heater”, and has a significant photothermal effect on polymer electrolyte, which results in higher temperature-rise (ΔT) from 1.2 °C to 9 °C, and improvement of the photo-thermal photo-to-electron conversion efficiency (η) from 4.19% to 6.28%, compared with the case without dyeing. [Display omitted] •A gel electrolyte with azobenzene-dyed, nanofibrous microstructure surface has been designed.•Incorporating with dye molecules can improve photothermal effect of gel electrolyte.•Solar energy utilization of the DSSC cell can be promoted using photo-heatable gel electrolyte. Insufficient ion capacity from a room temperature polymer electrolyte is commonly a short slab of the solid-state photoelectrochemical systems, like solid-state dye-sensitized solar cells (S-DSSCs). To overcome this drawback, herein a facile strategy based on the light-induced temperature-rise effect on the electrolyte has been given. By applying a photo-heatable, well-nanostructured polymer electrolyte dyed with azobenzene, it is found that the azobenzene can remarkably increase the ion conductivity of the gel electrolyte, and obtain better light-harvesting efficiency. To explore the mechanism, differential scanning calorimeter and infrared imaging system are used to accurately evaluate the temperature rise of such electrolyte under different preparation or irradiation conditions. It shows that significant photothermal heating effect on the electrolyte can both benefit from the incorporated azobenzene as a “micro solar-heater” and the rich nanostructure of the matrix surface that increases the area of ​​interaction with light. Under standard sunlight, the azobenzene-stained polymer electrolyte can obtain a temperature rise from 1.2 °C (no staining) to 9 °C (dyeing), and the corresponding ionic conductivity increases up to about 40%. Accordingly, the photothermal photo-to-electron conversion efficiency of S-DSSC is significantly improved by ∼50%.