Long life all-solid-state electrochromic devices by annealing

Li, Wenjie; Zhang, Xiang; Chen, Xi; Zhao, Yingming; Sun, Wanxin; Xiao, Yingjun; Li, Senran; Zhao, Jiupeng; Li, Yao

doi:10.1016/j.solmat.2021.110992

Cited by 21 publications

(16 citation statements)

References 38 publications

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“…Haacke suggested n = 10 [ 54 ] and it is frequently used. However, in most cases, a visible transmittance of about 80% is considered appropriate [ 3,4,22,52 ] and, therefore, a value n = 5 has been selected to compare the present samples in Table 1 . This shows that their quality as transparent and conductive films increases with the oxygen partial pressure and after heating.…”

Section: Resultsmentioning

confidence: 99%

“…NiO is used in a variety of applications going from gas sensors, [ 1 ] supercapacitors, [ 2 ] or light emitting diodes [ 3 ] to electrochromic and photovoltaic devices. [ 4–6 ] This is due to its natural abundance, low toxicity, and strong stability, along with the versatility of its optical and electrical characteristics, which depend on the specific morphology, stoichiometry, and crystallinity of the material. [ 1,2 ]…”

Section: Introductionmentioning

confidence: 99%

“…[ 20,21 ] For NiO films grown at room temperature, postdeposition annealing in air at ≈400 ºC is usually applied to improve their crystallinity and durability for practical uses. [ 4,22 ] As experimental techniques are developed to control the optical and electrical characteristics of NiO thin films, interest in the evolution of acceptor defects and crystallinity as a function of preparation parameters is greatly increasing. In addition, it is important to elucidate the electrical conduction and optical absorption mechanisms that act in each case, which depend on the density of states and their degree of occupation.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Acceptor Defects on the Structural, Optical and Electrical Properties of Sputtered NiO Thin Films

Guillén

Herrero

2021

Physica Status Solidi (a)

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NiO thin films have many applications due to the versatility of their optical and electrical characteristics, which can be controlled by the deposition parameters and/or subsequent heating. To achieve proper control, understanding their behavior, it is necessary to establish the influence of acceptor defects on the electronic characteristics of the films in relation to the preparation procedure. For this purpose, polycrystalline NiO thin films are grown by reactive DC sputtering on unheated glass substrates, with different acceptor defects depending on the oxygen partial pressure in the sputtering gas mixture. Their structural, morphological, optical, and electrical properties are analyzed comparatively in the as‐grown conditions and after heating in air at 400 °C. The results indicate that nickel vacancies along with hole carriers are effectively increased in films prepared at high oxygen ratios, increasing the electrical conductivity and the optical absorption at low energies, while distorting the crystalline lattice and decreasing the mean crystallite size. The heat treatment improves the crystallinity, bringing the different samples toward an equilibrium state that equates their optical and electrical characteristics. The intrinsic equilibrium constant is in the order K i ≈ 1022 cm−6, whereas the hole effective mass is found dependent on the carrier concentration.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of Acceptor Defects on the Structural, Optical and Electrical Properties of Sputtered NiO Thin Films

Guillén

Herrero

2021

Physica Status Solidi (a)

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“…When elaborated in the form of a thin film, WO 3 switches from a colorless state to a dark blue state with the insertion of small cations M (H + , Li, and Na + ) according to WO 3 + x e – + x M + ⇔ M x WO 3 . Electrochromic tungsten oxide films can be amorphous or crystallized depending on the temperature during the elaboration process. − WO 3 is known to present a self-bleaching behavior under its reduced state, leading to an increase of the transmittance in open-circuit conditions after the coloration. , Some authors reported that an additional layer of Ta 2 O 5 on top of the WO 3 layer can contribute to increasing the persistence of the colored state of films or film-based devices once the applied voltage is withdrawn. , This property is called the memory effect which is defined by the persistence of the colored (or bleached) state for cathodic (anodic) electrochromic materials under open circuit conditions . Thereby, the applied voltage to obtain the desired state does not need to be applied continuously which leads to an increase in energy saving of the device.…”

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confidence: 99%

Toward the Prediction of Electrochromic Properties of WO₃ Films: Combination of Experimental and Machine Learning Approaches

Faceira

Teulé‐Gay

Rignanese

et al. 2022

J. Phys. Chem. Lett.

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WO 3 is the state of the art of electrochromic oxide materials finding technological application in smart windows. In this work, a set of WO 3 thin films were deposited by magnetron sputtering by varying total pressure, oxygen partial pressure, and power. On each film two properties were measured, the electrochemical reversibility and the blue color persistence of Li x WO 3 films in simulated ambient conditions. With the help of machine learning, prediction maps for such electrochromic properties, namely, color persistence and reversibility, were designed. High-performance WO 3 films were targeted by a global score which is the product of these two properties. The combined approach of experimental measurements and machine learning led to a complete picture of electrochromic properties depending of sputtering parameters providing an efficient tool in regards to time saving.

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“…To date, abundant studies were concentrated on one or two EC performance improvements of NiO x films such as steady cycles, rapid response time, high coloration efficiency, large optical modulation amplitude, even high capacitance and so on. [18,19] Diversified treatment methods were also adopted to achieve nanocrystallization and porous structure of NiO x films in order to gain better EC properties, [20] such as, heat treatment, doping and so on. [21,22] Our group have made some efforts in single or double elements doping in NiO x films which showed remarkable improvement.…”

mentioning

confidence: 99%

Electrochromic Adaptability of NiO_x Films Modified by Substrate Temperature in Aqueous and Non‐Aqueous Electrolytes

Ding

Wang

Mei

et al. 2022

Adv Materials Inter

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Depending on adjusting substrate temperature during film depositing, a series of NiOx films has been prepared by magnetron sputtering. The electrochromic (EC) advantage of NiOx films modified by substrate temperature is verified. Moderate heating substrate can improve surface charge transfer (from ≈30 to ≈40 mC cm−2) and energy storage capacity (45% increment) without damaging other performance effectively. Considering the different electrochemical mechanisms in varied electrolytes, the EC performance of NiOx films in two electrolytes is discussed. In KOH electrolyte, NiOx films at 300 °C substrates show prominent optical modulation (≈81%) and high charge capacity (≈40 mC cm−2). 300 °C heating compensates for the shortage of poor stability and tedious activation. In LiClO4‐PC electrolyte, NiOx films can undergo long‐term cycles compared with aqueous conditions, the coloration efficiency keeps high level (≈80 cm2 C−2) which means small charge quantities can drive a wide transmittance range. The cyclic discrepancy in two electrolytes can be ascribed to diverse reacted modes between electrolyte ions and NiOx films. In aqueous KOH electrolyte, EC process and activated state strongly relies on Ni2+ distribution on films surface, while NiOx experiences two phases oxidation to get thorough coloration in PC‐Li based electrolyte.

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Long life all-solid-state electrochromic devices by annealing

Cited by 21 publications

References 38 publications

Influence of Acceptor Defects on the Structural, Optical and Electrical Properties of Sputtered NiO Thin Films

Influence of Acceptor Defects on the Structural, Optical and Electrical Properties of Sputtered NiO Thin Films

Toward the Prediction of Electrochromic Properties of WO₃ Films: Combination of Experimental and Machine Learning Approaches

Electrochromic Adaptability of NiO_x Films Modified by Substrate Temperature in Aqueous and Non‐Aqueous Electrolytes

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Long life all-solid-state electrochromic devices by annealing

Cited by 21 publications

References 38 publications

Influence of Acceptor Defects on the Structural, Optical and Electrical Properties of Sputtered NiO Thin Films

Influence of Acceptor Defects on the Structural, Optical and Electrical Properties of Sputtered NiO Thin Films

Toward the Prediction of Electrochromic Properties of WO3 Films: Combination of Experimental and Machine Learning Approaches

Electrochromic Adaptability of NiOx Films Modified by Substrate Temperature in Aqueous and Non‐Aqueous Electrolytes

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Product

Resources

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Toward the Prediction of Electrochromic Properties of WO₃ Films: Combination of Experimental and Machine Learning Approaches

Electrochromic Adaptability of NiO_x Films Modified by Substrate Temperature in Aqueous and Non‐Aqueous Electrolytes