Defect engineering of W^(6+)-doped NiO for high-performance black smart windows

In this report,W^(6+)doping as a defect engineering strategy has been proposed to improve the electrochromic properties of NiO film.Further research was conducted to explore the electrochromic properties and the modified mechanism of W-doped NiO film.Compared to the pure NiO,W-doped NiO film exhibits improved electrochromic properties with significant optical modulation(61.56%at 550 nm),fast switching speed(4.42 s/1.40 s for coloring/bleaching),high coloration efficiency(45.41 cm^(2)·C-1)and outstanding cycling stability(no significant attenuation after 2000 cycles)in Li-based electrolytes.Density functional theory(DFT)calculations combined with the experimental results indicate that the improved electrochromic properties were due to enhanced the electronic conductivity and ion conductivity after the introduction of W^(6+).The charge capacity of W-doped NiO has also been improved,and it can function with WO_(3) to achieve a high performance black electrochromic smart window(ECSW)by balancing charge.This work could advance the fundamental understanding of defect engineering as an effective strategy to boost the electrochromic properties of NiO anodic material,manifesting a significant development as a candidate counter electrode in high-performance black smart windows.

CaF_(2):A novel electrolyte for all solid-state electrochromic devices

The energy consumption in building ventilation,air,and heating conditioning systems,accounts for about 25%of the overall energy consumption in modern society.Therefore,cutting carbon emissions and reducing energy consumption is a growing priority in building construction.Electrochromic devices(ECDs)are considered to be a highly promising energy-saving technology,due to their simple structure,active control,and low energy input characteristics.At present,Hþ,OH-and Liþare the main electrolyte ions used for ECDs.However,Hþand OH-based electrolytes have a high erosive effect on the material surface and have a relatively short lifetime.Liþ-based electrolytes are limited due to their high cost and safety concerns.In this study,inspired by prior research on Ca^(2+)þbatteries and supercapacitors,CaF_(2)films were prepared by electron beam evaporation as a Ca^(2+)þ-based electrolyte layer to construct ECDs.The structure,morphology,and optical properties of CaF_(2)films were characterized.ECDs with the structure of ITO(indium tin oxide)glass/WO3/CaF_(2)/NiO/ITO show short switching times(22.8 s for the coloring process,2.8 s for the bleaching process).Additionally,optical modulation of the ECDs is about 38.8%at 750 nm.These findings indicate that Ca^(2+)þbased ECDs have the potential to become a competitive and attractive choice for large-scale commercial smart windows.