title: High performing smart electrochromic device based on honeycomb nanostructured h-WO3 thin films: hydrothermal assisted synthesis.
abstract: Herein, we report honeycomb nanostructured single crystalline hexagonal WO(3) (h-WO(3)) thin films in order to improve electrochromic performance. In the present investigation, honeycomb nanostructured WO(3) with different unit size and nanowire array with highly nanocrystalline frameworks have been synthesized via a hydrothermal technique. The influence of hydrothermal reaction time on the honeycomb unit cells, crystallite size, lithium ion diffusion coefficient and switching time for coloration/bleaching were studied systematically. The electrochromic study reveals that the honeycomb unit cell size has a significant impact on the electrochromic performance. Small unit cells in the honeycomb lead to large optical modulation and fast switching response. A large optical modulation in the visible spectral region (60.74% at λ = 630 nm) at a potential of -1.2 V with fast switching time (4.29 s for coloration and 3.38 s for bleaching) and high coloration efficiency (87.23 cm(2) C(-1)) is observed in the honeycomb WO(3) thin films with a unit cell diameter of 1.7 μm. The variation in color on reduction of WO(3) with applied potential has been plotted on an xy-chromaticity diagram and the color space coordinate shows the transition from a colorless to deep blue state.
authors.affiliation: Materials Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur, 416004, MS, India. p_n_bhosale@rediffmail.com.
authors.forename: Vijay V
authors.initials: VV
authors.lastname: Kondalkar
authors.forename: Sawanta S
authors.initials: SS
authors.lastname: Mali
authors.forename: Rohini R
authors.initials: RR
authors.lastname: Kharade
authors.forename: Kishorkumar V
authors.initials: KV
authors.lastname: Khot
authors.forename: Pallavi B
authors.initials: PB
authors.lastname: Patil
authors.forename: Rahul M
authors.initials: RM
authors.lastname: Mane
authors.forename: Sipra
authors.initials: S
authors.lastname: Choudhury
authors.forename: Pramod S
authors.initials: PS
authors.lastname: Patil
authors.forename: Chang K
authors.initials: CK
authors.lastname: Hong
authors.forename: Jin H
authors.initials: JH
authors.lastname: Kim
authors.forename: Popatrao N
authors.initials: PN
authors.lastname: Bhosale