Effect of carrier concentration on the optical band gap of TiO2 nanoparticles

Munir, Shamsa; Shah, Syed Mujtaba; Hussain, Hidayat; Khan, Rafaqat Ali

doi:10.1016/j.matdes.2015.12.022

Cited by 115 publications

(50 citation statements)

References 23 publications

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“…After being coupled with BiVO 4 , the absorption in the visible light region between 400 and 500 nm of BiVO 4 /TiO 2 /Ti heterojunction film increases with the increase in the amount of BiVO 4 , and the absorption edge shifts to 450 nm for the BiVO 4 /TiO 2 /Ti film prepared with 1000 s electrodeposition time. The band gap of a semiconductor can be calculated by employing the following equation [28]:

{false(a h v false)}^{2} = h v - E_{normalg},

where a is the absorption coefficient, v is the light frequency and E g is the band gap of a semiconductor. From the curve of ( ahv ) 2 versus hv shown in figure 3 b , the energy of the band gap of TiO 2 /Ti film is 3.20 eV, which is the same as the result reported before [29].…”

Section: Resultsmentioning

confidence: 99%

Preparation of nanoporous BiVO ₄ /TiO ₂ /Ti film through electrodeposition for photoelectrochemical water splitting

Hong-xing

Liu

2018

R. Soc. open sci.

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A nanoporous BiVO4/TiO2/Ti film was successfully fabricated by electrodepositing a nanoporous BiOI film on nanoporous TiO2 arrays followed by annealing at 450°C for 2 h. The electrodeposition of BiOI film was carried out at different times (10, 30, 100, 500 and 1000 s) in Bi(NO3)3 and KI solution. The morphological, crystallographic and photoelectrochemical properties of the prepared BiVO4/TiO2/Ti heterojunction film were examined by using different characterization techniques. UV–vis spectrum absorption studies confirmed an increase in absorption intensities with increasing electrodeposition time, and the band gap of BiVO4/TiO2/Ti film is lower than that of TiO2/Ti. The photocatalytic efficiency of BiVO4/TiO2/Ti heterojunction film was higher compared to that of the TiO2/Ti film owing to the longer transient decay time for BiVO4/TiO2/Ti film (3.2 s) than that of TiO2/Ti film (0.95 s) in our experiment. The BiVO4/TiO2/Ti heterojunction film prepared by electrodeposition for 1000 s followed by annealing showed a high photocurrent density of 0.3363 mA cm−2 at 0.6 V versus saturated calomel electrode. Furthermore, the lowest charge transfer resistance from electrochemical impedance spectroscopy was recorded for the BiVO4/TiO2/Ti film (1000 s) under irradiation.

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{false(a h v false)}^{2} = h v - E_{normalg},

Section: Resultsmentioning

confidence: 99%

Preparation of nanoporous BiVO ₄ /TiO ₂ /Ti film through electrodeposition for photoelectrochemical water splitting

Hong-xing

Liu

2018

R. Soc. open sci.

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“…The UV-Vis DR spectra in the 190-800 nm range of the samples were recorded at room temperature using an Ocean Optics Inc. spectrometer (Mini-DT2) provided with a diffuse reflectance accessory. The optical energy bandwidth of the different semiconductor CdS and Zn x Cd 1−x S systems were calculated using the Kubelka-Munk (K-M) function [44] and Tauc's plot method [45][46][47] in which the linear part of the curve is extrapolated to find its intersection with the horizontal axis. A JEOL brand scanning electron microscope, model JSM-6390L, was used at 20 kV.…”

Section: Characterization Methodsmentioning

confidence: 99%

Structural, Optical and Photocatalytic Characterization of ZnxCd1−xS Solid Solutions Synthetized Using a Simple Ultrasonic Radiation Method

et al. 2020

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A simple ultrasonic radiation method was employed for the preparation of zinc and cadmium sulfide solid solution (ZnxCd1−xS; x = 0–0.25 wt.%) with the aim to investigate its efficiency for H2 production via a visible light-driven water-splitting reaction. The catalyst characterization by X-ray diffraction confirmed the formation of solid solution (ZnxCd1−xS) between CdS and ZnS phases. All catalysts exhibited hierarchical morphology (from SEM and TEM) formed by aggregated nanoparticles of ZnxCd1−xS solid solution with crystals showing mainly (111) planes of cubic CdS phase. The crystal size linearly decreased with an increase in Zn incorporation in the crystal lattice (from 4.37 nm to 3.72 nm). The ZnxCd1−xS photocatalysts showed a gradual increase in the H2 evolution, with an increase in the Zn concentration up to 0.2 wt.% making the most effective Zn0.2Cd0.8S catalyst toward H2 production. From the catalyst activity–structure correlation, it has been concluded that the twin-like CdS structure, the (111) plane and specific morphology are the main factors influencing the catalyst effectivity toward H2 production. All those factors compensated for the negative effect of an increase in band gap energy (Ebg) after ZnS incorporation into solid solution (from 2.21 eV to 2.34 eV). The effect of the catalyst morphology is discussed by comparing H2 evolution over unsupported and supported Zn0.2Cd0.8S solid solutions.

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“…TiO 2 having wide band gap (3.2 eV) has been employed as a feasible electron acceptor for dye sensitized solar cells [15,19]. In the beginning it gave low efficiency (1%) which was tremendously enhanced when Gratzel used porous TiO 2 as anode material [20,21]. Low cost, high structure stability and photosensitivity of TiO 2 attracted the attention of researchers to develop new products [22,23].…”

Section: Introductionmentioning

confidence: 99%

Pyrocatechol violet sensitized Ho-TiO₂/ZnO nanostructured material: as photoanode for dye sensitized solar cells

Ullah

Shah

Hussain

et al. 2020

Mater. Res. Express

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In this work TiO 2 , Holmium doped (Ho-TiO 2 ) Titanium oxide nanoparticles (NPs) and the corresponding nanostructured combinations (Ho-TiO 2 /ZnO NC) were successfully synthesized through sol gel method and reflux techniques respectively. The prepared nano materials were characterized with the help of x-ray diffraction Analysis (XRD), UV-visible spectroscopy, Scanning Electron Microscopy (SEM), Energy dispersive x-ray Analysis (EDX) and Fourier Transform infrared spectroscopy (FT-IR). The absorption spectra of nano materials were used for band gaps calculation. The band gap of pure TiO 2 NPs was found to be 3.10 eV which was effectively tuned to 2.65 eV by the doping of Holmium at different concentrations. XRD patterns confirmed the crystalline nature and purity of the synthesized nano materials. Morphology and elemental composition of the material were investigated using SEM and EDX respectively. FTIR helped in detecting the functional groups and grafting of the dye on the surface of nanoparticles. The nano materials were used as Photo-anodes in dye sensitized solar cells (DSSC). Pyrocatechol Violet dye was used as a photo-sensitizer. P3HT (polymer), a hole conducting polymer, was employed as a solid state electrolyte. I-V measurements were used for characterization of fabricated solar cells. Ho-TiO 2 /ZnO nanomaterial photosensitized with Pyrocatechol violet dye gave the highest percentage efficiency of 1.51. Other characteristic parameters of the fabricated devices such as short circuit current (Jsc), open circuit voltage (Voc), maximum power point (Mpp) and fill factor were found to be 11.2 mA cm −2 , 0.41 V, 1.55(mW cm −2 ) and 0.33 respectively.

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Effect of carrier concentration on the optical band gap of TiO2 nanoparticles

Cited by 115 publications

References 23 publications

Preparation of nanoporous BiVO ₄ /TiO ₂ /Ti film through electrodeposition for photoelectrochemical water splitting

Preparation of nanoporous BiVO ₄ /TiO ₂ /Ti film through electrodeposition for photoelectrochemical water splitting

Structural, Optical and Photocatalytic Characterization of ZnxCd1−xS Solid Solutions Synthetized Using a Simple Ultrasonic Radiation Method

Pyrocatechol violet sensitized Ho-TiO₂/ZnO nanostructured material: as photoanode for dye sensitized solar cells

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Effect of carrier concentration on the optical band gap of TiO2 nanoparticles

Cited by 115 publications

References 23 publications

Preparation of nanoporous BiVO 4 /TiO 2 /Ti film through electrodeposition for photoelectrochemical water splitting

Preparation of nanoporous BiVO 4 /TiO 2 /Ti film through electrodeposition for photoelectrochemical water splitting

Structural, Optical and Photocatalytic Characterization of ZnxCd1−xS Solid Solutions Synthetized Using a Simple Ultrasonic Radiation Method

Pyrocatechol violet sensitized Ho-TiO2/ZnO nanostructured material: as photoanode for dye sensitized solar cells

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Preparation of nanoporous BiVO ₄ /TiO ₂ /Ti film through electrodeposition for photoelectrochemical water splitting

Preparation of nanoporous BiVO ₄ /TiO ₂ /Ti film through electrodeposition for photoelectrochemical water splitting

Pyrocatechol violet sensitized Ho-TiO₂/ZnO nanostructured material: as photoanode for dye sensitized solar cells