A comparison of thermo- and photo-chromic behaviour in films of amorphous WO3

Goulding, M.; Thomas, C. B.; Hurditch, Rodney J.

doi:10.1016/0038-1098(83)90574-4

Cited by 24 publications

(8 citation statements)

References 6 publications

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“…A longer irradiation time will result in a larger photochromic response [22]. This photochromic phenomenon is observed most prominently in thin films of tungsten oxide [8,, which can be prepared by thermal evaporation [8, 26-28, 44, 45, 47, 48, 68, 71], reactive evaporation [44,72] rf sputtering [22,29,37,44,71], dc sputtering [54], electron beam deposition [34,60], sol-gel-related techniques [24,38,55,73,74], spray pyrolysis [47], electrodeposition [63,64], laser-related deposition technique [51,52,58] and so on. Different techniques for the film preparation often lead to thin films with somewhat different properties.…”

Section: Photochromic Behaviormentioning

confidence: 99%

“…The injected cations for these two processes are K + and H + , respectively. Although during the photochromic process film stress is observed in WO 3 film due to the insertion of protons [22], the radius of proton is too small to cause enough changes in oxide structure that can produce the intermediate states accessible to the visible light, or such kind of change corresponding to the strains are inaccessible to the visible light. The radius of alkali ions is large enough to produce such kind of states [125].…”

Section: Visible Light Coloration Induced By Cathodic Polarizationmentioning

confidence: 99%

“…For instance, electrical conductivity [8,28,44,58] and photoconductivity [8] of WO 3 films increase greatly after the photo-excitation. During the photochromic process film strains are observed in WO 3 film due to the insertion of protons [22].…”

Section: Photochromic Behaviormentioning

confidence: 99%

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Photochromism in transition-metal oxides

He¹,

Yao²

2004

Res. Chem. Intermed.

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Transition-metal oxides -including tungsten oxide, molybdenum oxide, titanium dioxide, vanadium pentoxide, niobium pentoxide and zinc oxide -exhibit photochromism upon bandgap excitation. These oxides constitute an important group of inorganic chromogenic materials, which is of great significance in the perspective of science and technology. During the past several decades, great progresses have been made in the microstructure, photochromic behavior and mechanism of these oxides, specifically of tungsten oxide. These studies underscore the opportunity of using these materials in photonic applications. The details will be presented in this review.

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Section: Photochromic Behaviormentioning

confidence: 99%

Section: Visible Light Coloration Induced By Cathodic Polarizationmentioning

confidence: 99%

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Photochromism in transition-metal oxides

He¹,

Yao²

2004

Res. Chem. Intermed.

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“…,17 However, we hypothesized that WO 3 crystalline a)Author to whom correspondence should be addressed. Electronic mail: hirie@yamanashi.ac.jp…”

mentioning

confidence: 99%

“…[15][16][17] As WO 3 is reduced at 1070 K, the oxygen (O) nonstoichiometry results in the generation of electrons (O O ! V O •• þ 2e À þ 1/2O 2 ) that act as charge carriers, a property that is consistent with the negative value of S. 15 The thermoelectric property of amorphous WO 3 films colored either photo-or thermo-chromically was also reported, demonstrating that "irreversible" changes in the thermoelectric properties of this material accompany the photochromic changes.…”

mentioning

confidence: 99%

Photo-controllable thermoelectric properties with reversibility and photo-thermoelectric effects of tungsten trioxide accompanied by its photochromic phenomenon

Azuma

Kawano

Kakemoto

et al. 2014

Journal of Applied Physics

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The addition of photo-controllable properties to tungsten trioxide (WO3) is of interest for developing practical applications of WO3 as well as for interpreting such phenomena from scientific viewpoints. Here, a sputtered crystalline WO3 thin film generated thermoelectric power due to ultraviolet (UV) light-induced band-gap excitation and was accompanied by a photochromic reaction resulting from generating W5+ ions. The thermoelectric properties (electrical conductivity (σ) and Seebeck coefficient (S)) and coloration of WO3 could be reversibly switched by alternating the external stimulus between UV light irradiation and dark storage. After irradiating the film with UV light, σ increased, whereas the absolute value of S decreased, and the photochromic (coloration) reaction was detected. Notably, the opposite behavior was exhibited by WO3 after dark storage, and this reversible cycle could be repeated at least three times. Moreover, photo-thermoelectric effects (photo-conductive effect (photo-conductivity, σphoto) and photo-Seebeck effect (photo-Seebeck coefficient, Sphoto)) were also detected in response to visible-light irradiation of the colored WO3 thin films. Under visible-light irradiation, σphoto and the absolute value of Sphoto increased and decreased, respectively. These effects are likely attributable to the excitation of electrons from the mid-gap visible light absorption band (W5+ state) to the conduction band of WO3. Our findings demonstrate that the simultaneous, reversible switching of multiple properties of WO3 thin film is achieved by the application of an external stimulus and that this material exhibits photo-thermoelectric effects when irradiated with visible-light.

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Advances in Reversible Luminescence Modification and Applications of Inorganic Phosphors Based on Chromism Reaction

Haider,

Zhao,

et al. 2023

Advanced Optical Materials

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The reversible luminescence modification of inorganic phosphors has emerged as a promising field, enabling innovative applications such as optical memory, multiple anti‐counterfeiting, and photoswitches. Traditional luminescence modulation techniques, such as core–shell structure design and energy transfer‐related luminescent ions regulation, face challenges in achieving reversible luminescence modification. Chromism induces reversible color changes in materials when stimulated by external fields such as electricity, heat, and light. Combining chromism with luminescence enables the creation of chromism‐driven reversible luminescence manipulation in a single material. This review summarizes recent advances in reversible luminescence modification of inorganic phosphors based on chromism reaction and highlights their potential applications in optical data storage, fingerprint acquisition, and anti‐counterfeiting areas. The potential prospective research directions are also discussed and the challenges and opportunities of chromism‐based reversible luminescent materials are presented for further extended applications.

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A comparison of thermo- and photo-chromic behaviour in films of amorphous WO3

Cited by 24 publications

References 6 publications

Photochromism in transition-metal oxides

Photochromism in transition-metal oxides

Photo-controllable thermoelectric properties with reversibility and photo-thermoelectric effects of tungsten trioxide accompanied by its photochromic phenomenon

Advances in Reversible Luminescence Modification and Applications of Inorganic Phosphors Based on Chromism Reaction

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