TY - JOUR
T1 - Electrochromic Behavior Originating from the W6+/W5+Redox in Aurivillius-type Tungsten-Based Layered Perovskites
AU - Iimura, Reona
AU - Hasegawa, Takuya
AU - Yin, Shu
N1 - Funding Information:
This work was supported by JSPS KAKENHI under Grant Nos. JP20K15106 and 20H00297, Nippon Sheet Glass Foundation for Materials Science and Engineering, the Dynamic Alliance for Open Innovations Bridging Human, Environment, and Materials, and the Cooperative Research Program of “Network Joint Research Center for Materials and Devices”. The XAFS measurements were performed with the BL12C at the Photon Factory (PF) with the approval of the High Energy Accelerator Research Organization (KEK) (Proposal Nos. 2020P001 and 2021G608).
Publisher Copyright:
© 2022 American Chemical Society.
PY - 2022/2/7
Y1 - 2022/2/7
N2 - Simple oxide materials, typically, WO3, have been conventionally employed for electrochromic (EC) materials because of their high coloration efficiency; however, it is quite difficult to realize multiple coloration because they involve redox reactions due to single ions. On the other hand, multiple oxides are expected to show various colors when applying different voltages due to the diverse structures and combinations of ions; however, multiple oxide-type EC materials are still in the research stage, and the discovery of further EC materials is necessary. Toward the development of multiple oxide-type EC materials, tungsten-containing layered perovskites have been synthesized, and their optical properties have been evaluated. X-ray diffraction and X-ray absorption fine structure analyses revealed that the discovered tungsten-based layered perovskites Bi2Na0.5La0.5TiWO9 (BNLTW) and Bi2LaTi1.5W0.5O9 (BLTW) have an orthorhombic phase with an Aurivillius-type layered perovskite structure. EC devices fabricated with three kinds of perovskites, including well-known Aurivillius-type Bi2W2O9 (BWO), have no absorption in the visible-light region when no voltage is applied, while they show absorption over the whole visible-light spectrum to black when a voltage of +4.5 V is applied. Furthermore, with an applied voltage of -4.5, the transmittance recovered to the same level as the initial state, meaning the EC function is reversible. In this reaction, only tungsten in the perovskite framework acted as a redox-active species (W6+/W5+ redox) without the redox of the other metal ions. From the electrochemical analysis of the EC materials using cyclic voltammetry, redox peaks could be observed at -0.2 to 0.4 V for reduction and +0.1 to +0.3 V for oxidation. Interestingly, the redox potentials are linearly related to the W content in the perovskite unit, indicating that the redox potentials can be tuned by controlling the chemical formula. The coloration efficiency of the BNLTW EC device was the best at 37.1 cm2/C in the prepared perovskite-based EC device, which is comparable to that of a typical WO3 EC material.
AB - Simple oxide materials, typically, WO3, have been conventionally employed for electrochromic (EC) materials because of their high coloration efficiency; however, it is quite difficult to realize multiple coloration because they involve redox reactions due to single ions. On the other hand, multiple oxides are expected to show various colors when applying different voltages due to the diverse structures and combinations of ions; however, multiple oxide-type EC materials are still in the research stage, and the discovery of further EC materials is necessary. Toward the development of multiple oxide-type EC materials, tungsten-containing layered perovskites have been synthesized, and their optical properties have been evaluated. X-ray diffraction and X-ray absorption fine structure analyses revealed that the discovered tungsten-based layered perovskites Bi2Na0.5La0.5TiWO9 (BNLTW) and Bi2LaTi1.5W0.5O9 (BLTW) have an orthorhombic phase with an Aurivillius-type layered perovskite structure. EC devices fabricated with three kinds of perovskites, including well-known Aurivillius-type Bi2W2O9 (BWO), have no absorption in the visible-light region when no voltage is applied, while they show absorption over the whole visible-light spectrum to black when a voltage of +4.5 V is applied. Furthermore, with an applied voltage of -4.5, the transmittance recovered to the same level as the initial state, meaning the EC function is reversible. In this reaction, only tungsten in the perovskite framework acted as a redox-active species (W6+/W5+ redox) without the redox of the other metal ions. From the electrochemical analysis of the EC materials using cyclic voltammetry, redox peaks could be observed at -0.2 to 0.4 V for reduction and +0.1 to +0.3 V for oxidation. Interestingly, the redox potentials are linearly related to the W content in the perovskite unit, indicating that the redox potentials can be tuned by controlling the chemical formula. The coloration efficiency of the BNLTW EC device was the best at 37.1 cm2/C in the prepared perovskite-based EC device, which is comparable to that of a typical WO3 EC material.
UR - http://www.scopus.com/inward/record.url?scp=85124175360&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85124175360&partnerID=8YFLogxK
U2 - 10.1021/acs.inorgchem.1c03364
DO - 10.1021/acs.inorgchem.1c03364
M3 - Article
C2 - 35067050
AN - SCOPUS:85124175360
SN - 0020-1669
VL - 61
SP - 2509
EP - 2516
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 5
ER -