Electrochromism of Nanocrystal-in-Glass Tungsten Oxide Thin Films under Various Conduction Cations

Abstract

The nanocrystal-in-glass (nanocrystals embedded amorphous matrix) tungsten oxide (WO 3 ) thin films with a nanoporous characteristic were prepared via an electron beam evaporation technique. The e-beam evaporated WO 3 thin films present a fast colored/bleached time of 16/11, 16/ 14, and 12/12 s, a large optical modulation of 92, 91, and 87% at 633 nm, and a high coloration efficiency of 61.78, 62.04, and 67.59 cm 2 C −1 in Li + , Na + , and Al 3+ electrolytes, respectively. On one hand, the improved electrochromic performance is mainly attributed to the short diffusion distance and buffering effect in the host matrix, which facilitates the ion insertion/ extraction and alleviates the structural collapse of the framework. On the other, owing to the strong electrostatic interactions between the trivalent cations and the host, the WO 3 thin films in Al 3+ possess a shallow diffusion depth and long cycle life. The individual contribution from the capacitance-or diffusion-controlled process is comprehensively demonstrated. Pseudocapacitive behavior in the nanocrystal-in-glass WO 3 thin films is in favor of fast kinetics response and sound cycling stability. Our work offers an in-depth insight of the electrochromic mechanism for nanocrystal-in-glass WO 3 thin films in various electrolytes and sheds light on the fundamental principle in the electrochromic devices.

Rechargeable Aqueous Hybrid Zn2+/Al3+ Electrochromic Batteries

“…Moreover, the surface Al 3+ intercalation region is expected to stabilize the WO 3 film in the electrolyte. 6,11,17 The above findings provide further proof of Al 3+ and Zn 2+ intercalation in WO 3 .…”

The discovery of conductive ionic bonds in NiO/Ni transparent counter electrodes for electrochromic smart windows with an ultra-long cycling life

“…The switching speed of electrochromic devices is essentially dependent on the ion diffusion coefficient and ion diffusion distance. 44 As shown in Fig. 4D, the colouration (tc) and bleaching (tb) times of NiO/Ni-1, defined as the time required for 90% of the full optical modulation, are 4.5 s and 5 s, respectively, which are faster than those of previously reported NiO, 11 WO 3 , 45 TiO 2-x 46 films.…”

Boosting Transport Kinetics of Ions and Electrons Simultaneously by Ti3C2Tx (MXene) Addition for Enhanced Electrochromic Performance

“…Starting with the fundamental electrochemical reaction, electrochromic performances of the WO 3− x depend on the transport rate of the cations and electrons as well as the ability to accommodate the cations in the film. Different advanced strategies have been studied to improve electrochromic performances such as the combination of crystalline and amorphous WO 3− x [ 20 , 21 ], regulation of nanotopography [ 6 , 22 , 23 ], element doping [ 18 , 24 , 25 ], and construction of composite materials [ 26 , 27 ]. On the one hand, the structure construction of tungsten oxide almost concentrates on the transport behavior of cations.…”