Tuning of crystal phase structure in hydrated WO3 nanoparticles under wet chemical conditions and studies on their photochromic properties

Songara, Sandhya; Gupta, Vatsana; Patra, Manoj Kumar; Singh, Jitendra Kumar; Saini, Lokesh; Gowd, Genekehal Siddaramana; Vadera, Sampat Raj; Kumar, Narendra

doi:10.1016/j.jpcs.2012.02.020

Cited by 77 publications

(49 citation statements)

References 42 publications

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“…This is because, first, WO 3 has two distinctive characteristics, namely electrochromism [21,22,47,48] and photochromism, [49][50][51][52][53] arising from the formation of tungsten bronze by reaction with cations such as H + , Na + , and Li + , which simultaneously stores energy. Second, charging and discharging WO 3 , a negative electrode material for supercapacitors, [5,21,22,54,55] needs a negative bias, which may promote reactions with small cations in photoelectrochemical systems.…”

Section: Resultsmentioning

confidence: 99%

Capacitance Enhancement in a Semiconductor Nanostructure‐Based Supercapacitor by Solar Light and a Self‐Powered Supercapacitor–Photodetector System

Zhu

Huang

Pei

et al. 2016

Adv Funct Materials

149

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The effects of the environment on the energy storage of supercapacitors as well as the underlying mechanisms have long been neglected. This paper reports that the capacitance of hexagonal‐phase tungsten oxide (h‐WO3)‐based supercapacitors increases by ≈17% under solar light. Thorough analyses of the wavelength dependence of the enhancement, capacitive mechanism, energy storage dynamics, and impedance reveal that: i) photoexcited electrons are responsible for the enhancement; ii) the insertion of protons into the large hexagonal tunnels of h‐WO3, instead of a surface capacitive process, is greatly facilitated by the photoexcited electrons; iii) the theoretical light‐induced capacitance enhancement can reach up to 38% for a h‐WO3‐based supercapacitor. Moreover, as an application of this finding, a self‐powered photodetector based on a h‐WO3 supercapacitor is fabricated, wherein the photoexcited electrons serve as the signal for detecting solar light. The device works without an external power source and can be considered as an ultimately integrated power source–sensor system. This work sheds light on the interaction between solar light and a semiconductor‐based supercapacitor as well as the concrete mechanisms behind the phenomenon. These efforts also open the door to the design of highly integrated, brand‐new power source–sensor systems.

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Section: Resultsmentioning

confidence: 99%

Capacitance Enhancement in a Semiconductor Nanostructure‐Based Supercapacitor by Solar Light and a Self‐Powered Supercapacitor–Photodetector System

Zhu

Huang

Pei

et al. 2016

Adv Funct Materials

149

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“…11. Product obtained from non-acetified precursor solution indicates the coexistence of two WO X polymorphs, namely, monoclinic (m-WO 3 The enhancement in lithium ion diffusion rate, and hence faster electrochemical response, is expected for films containing orthorhombic hydrate (ortho-WO 3 Á 0.33H 2 O) NPs due to the higher electronic conductivity of this phase when comparing to monoclinic (m-WO 3 ) nanocrystals [40]. Therefore, the products of synthesis from PTA dissolved in non-acidified and 0.3 M HCl seem to be the most desirable, as long as the crystallinity is concerned.…”

Section: Structure and Morphology Of Synthesized Productsmentioning

confidence: 99%

“…One of the most active trends in applied electrochemistry is the development of metal oxide (MO X ) nanoparticles (NPs) with structural, electrical, and optical properties tailored to the specific application such as chromic devices [1][2][3], photovoltaic cells [4], photocatalytic systems [5][6][7][8], energy storage devices [9][10][11][12][13], electrolyte-gated TFTs [14,15], gas sensors [16][17][18], and electrocatalytic biosensors [19,20] (see Table 1). Features of those nanostructures are equally as important as their processability, enabling thin-film formation with desired functionality [21,22].…”

Section: Introductionmentioning

confidence: 99%

“…It was demonstrated that the application of ink-jet printing for deposition of MO X dispersion provides an excellent method for the production of inorganic thin films with controlled composition and microstructure for electrochemical devices such as dye-synthesized solar cells (DSCs) [27] and electrochromic (EC) windows/displays [28,29]. The use of printing techniques is particularly promising for electrochemically active film development, because of its merits of low 3 Hydrothermal growth using crystal seeds [26] TiO 2 Ink-jet printing Dye-sensitized solar cells [27] a-WO 3 /TiO 2 /WO Xprocessing energy, precise patterning with reduced raw material waste, high throughput, and flexibility in deposited film composition.…”

Section: Introductionmentioning

confidence: 99%

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Metal Oxide Nanoparticle Engineering for Printed Electrochemical Applications

Wójcik

Pereira

Martins

et al. 2015

Handbook of Nanoelectrochemistry

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Engineering procedures governing the selection or development of printable nanostructured metal oxide nanoparticles for chromic, photovoltaic, photocatalytic, sensing, electrolyte-gated TFTs, and power storage applications are established in this chapter. The main focus is given on how to perform the material selection and formulation of printable dispersion in order to develop functional films for electrochemical applications.This chapter is divided into four main parts. Firstly, a brief introduction on electrochemically active nanocrystalline metal oxide films developed via printing techniques is given. This is followed by the description of the film morphology, structure, and required functionality. A theoretical approach to understand the impact of size and shape of nanoparticles on an ink formulation and electrochemical performance being the subject of the third section provides a greater control over the material selection. We attempt to describe these properties and show that for a given material, geometry and size of the nanoparticles have a major influence on the electrochemical reactivity and response time. This gives the ability to tune the performance of the film simply by varying the morphology of incorporated nanostructures. This section is completed by the recommendations on each major step of an ink formulation, together with imposed critical constraints concerning the fluid control. Finally, the performance of the ink-jet-printed dual-phase electrochromic films is discussed as a case study.By providing such a rather systematic survey, we aim to stress the importance of proper design strategy that would result in both improved physicochemical properties of nanoparticle-loaded inks and enhanced electrochemical performance of printed functional films.

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“…Vibrational spectra of molecules are studied exper imentally by the methods of Raman scattering [47][48][49][50][51][52][53][54] and Fourier transform infrared (FTIR) spectros copy [55][56][57][58][59][60][61][62][63][64][65][66][67][68].…”

Section: Chemical Compositionmentioning

confidence: 99%