Spectrophotometric method for optical band gap and electronic transitions determination of semiconductor materials

Sangiorgi, Nicola; Aversa, Lucrezia; Tatti, Roberta; Verucchi, Roberto; Sanson, Alessandra

doi:10.1016/j.optmat.2016.11.014

Cited by 128 publications

(46 citation statements)

References 40 publications

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“…The bandgaps estimated using the Tauc plot method in some cases significantly deviated from those obtained through the CoW method. Methods to determine the electronic transition type as suggested by Sangiorgi et al (2017) for use in the Tauc plot method failed. 46 While complex absorption spectra for LDHs have been observed in the past 19,22,43,45 , few have made attempts at explaining deviations from clean absorption edges.…”

Section: Bandgap Determinationmentioning

confidence: 99%

Modification of Layered Double Hydroxides Using First-Row Transition Metals for Superior UV-Vis-NIR Absorption and the Influence of the Synthesis Method Used

Gevers¹,

Naseem²,

Sheppard³

et al. 2020

Preprint

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<div>Layered double hydroxides (LDHs) with high and tailorable UV-Vis-NIR absorption were prepared through transition</div><div>metal (TM) modification. The synthesis method used and amount of TM present were found to influence the UV-Vis-</div><div>NIR absorption intensity, -range, and the optical bandgap.</div><div><div>It was found that the incorporation of TMs in MgAl-LDH results in the existence of a "UV-Vis-NIR absorption fingerprint", the intensity of which can be tuned by the amount of TM present. There also exist differences in the UV-Vis-NIR absorption spectra and bandgaps obtained for MgAl-LDH synthesised using different synthesis conditions and methods, but these are not as visible when including transition metals. Further, the materials exhibit very complex spectra for which adequate explanation is lacking in literature. Finally, standard methods to determine the bandgap of materials, did not give conclusive results for all materials, only for some, and indicate that some of the materials might have multiple different transition types.</div></div>

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Section: Bandgap Determinationmentioning

confidence: 99%

Modification of Layered Double Hydroxides Using First-Row Transition Metals for Superior UV-Vis-NIR Absorption and the Influence of the Synthesis Method Used

Gevers¹,

Naseem²,

Sheppard³

et al. 2020

Preprint

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“…Cano-Casanova et al [40] concluded that the higher the composition of anatase phase in TiO2 nanocrystals, the lower the Eg values of respective TiO2. In fact, N. Sangiorgi et al [39] further strengthen the hypothesis by correlating the Eg values with lattice parameters, polycrystalline, amorphous phases and grain boundaries. Thus, the addition of AA to TiO2 nanocrystals contributed to the alteration of TiO2 crystallographic features and shifted the range of absorption into the visible region.…”

Section: Fig 3 Druv-vis Plot Of All Tio2 Nanocrystals A) Abs Vs Wamentioning

confidence: 84%

“…To limit possible errors in the estimation of band gap energy (Eg), the values of Kubelka-Munk function F(R) were directly recorded from the DRUV-vis spectroscopy. Meanwhile, the usual practice is by converting the reflectance data (%R) into absorption mode as reported by several researchers [37][38][39]. Then, it will be plotted in Kubelka-Munk plot, [(F(R).hυ] 1/n vs hυ where n = 2 for indirect transition and n = ½ direct transition.…”

Section: Fig 3 Druv-vis Plot Of All Tio2 Nanocrystals A) Abs Vs Wamentioning

confidence: 99%

Synthesis of ascorbic acid enhanced TiO2 photocatalyst: its characterization and catalytic activity in CO2 photoreduction

2018

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To date, the development of solar environmental remediation has shifted more emphasis on the green and simple synthesis of catalyst for CO2 photocatalysis process. Herein, TiO2 photocatalyst was successfully synthesized via hydrothermal method. The effects of the different molar ratio of ascorbic acid C6H8O6, (AA) added during the preparation of TiO2 nanoparticles were comprehensively studied. The characterization of TiO2 nanocrystals was performed via XRD, XPS, DRUV-vis, and FTIR. The results show the AA loading into TiO2 nanoparticles significantly intensified the XRD spectra of anatase structure. In fact, this feature had signified a reactivity of the photocatalyst in the visible region. In an instance, BET surface area was also enhanced with the highest recorded value of 135.14 m2/g for 0.8AA. Meanwhile, the CO2 photoreduction over synthesized TiO2 had produced the highest amount of HCOOH at 39.3 μmol/g cat for 0.8AA within 6 hours of reaction time. Furthermore, the DRUV-vis analysis had illustrated better light absorption ability of 0.8AA. This profound finding is attributed to the correlation between large surface area, pure anatase phase, and high adsorbed water molecules. Therefore, this study had significantly demonstrated the potential of modified TiO2 with AA in CO2 photocatalysis area while simultaneously presents a green and simple method for TiO2 synthesis.

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“…To determine the bandgap of a powder sample using the diffuse reflectance spectrophotometer is a common technique [56]. So, in this study the band-gap energy is calculated using a Kubelka-Munk method [57] based on the equation below:…”

Section: Analysis Of Diffuse Reflectance Uv-vis Spectroscopymentioning

confidence: 99%

Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis of Nano-LaCrO₃

Situmeang¹

2020

Pectins - Extraction, Purification, Characterization and Applications

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The use of environmentally friendly chemicals as the emulsifying agent in the preparation of the advanced materials is a focus and is very interesting to do. Although the focus is important, the advanced material that is made remains a top priority regarding characterization and its activity. One of the chemicals for making advanced and environmentally friendly materials such as LaCrO 3 perovskite is pectin functioning as the emulsifying agent. In general, perovskite compounds are materials with very wide applications such as fuel cells, electronic equipment, sensors, magnetic materials, photoluminescent materials, thermic catalysts, and photocatalysts. Furthermore, the use of various solvents to produce perovskite compounds with the aim of getting good applications has been done a lot such as water, alcohols, or other organic solvents, respectively, in mixing precursors directly, precipitation and coprecipitation, microwave, auto-combustion, sol-gel, and hydrothermal methods. In this chapter, preparation of LaCrO 3 using pectin as an emulsifying agent will be discussed in advance together with characterization and application of LaCrO 3 in the photocatalytic reaction of dyes and cellulose conversion.

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Spectrophotometric method for optical band gap and electronic transitions determination of semiconductor materials

Cited by 128 publications

References 40 publications

Modification of Layered Double Hydroxides Using First-Row Transition Metals for Superior UV-Vis-NIR Absorption and the Influence of the Synthesis Method Used

Modification of Layered Double Hydroxides Using First-Row Transition Metals for Superior UV-Vis-NIR Absorption and the Influence of the Synthesis Method Used

Synthesis of ascorbic acid enhanced TiO2 photocatalyst: its characterization and catalytic activity in CO2 photoreduction

Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis of Nano-LaCrO₃

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Spectrophotometric method for optical band gap and electronic transitions determination of semiconductor materials

Cited by 128 publications

References 40 publications

Modification of Layered Double Hydroxides Using First-Row Transition Metals for Superior UV-Vis-NIR Absorption and the Influence of the Synthesis Method Used

Modification of Layered Double Hydroxides Using First-Row Transition Metals for Superior UV-Vis-NIR Absorption and the Influence of the Synthesis Method Used

Synthesis of ascorbic acid enhanced TiO2 photocatalyst: its characterization and catalytic activity in CO2 photoreduction

Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis of Nano-LaCrO3

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Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis of Nano-LaCrO₃