Theoretical and experimental investigations on the temperature dependence of the refractive index of amorphous silica

Guo, Yujia; Wang, Zhiyong; Qiu, Qi; Su, Jun; Wang, Yunxiang; Shi, Sheng‐Cai; Yu, Zhenning

doi:10.1016/j.jnoncrysol.2015.09.008

Cited by 18 publications

(4 citation statements)

References 20 publications

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“…In the silica–AuNP heterostructure, the thermal expansion and increasing electron–phonon scattering is the dominant mechanism that causes shifting and broadening of SPR in the AuNP core when compared to the change in dielectric permittivity of the surrounding silica matrix . Therefore, an approach with additional intraband (Drude model) and interband model from previous literature was used to fit Otter’s experimental data (Supporting Information S1.2). − Similarly, since the rise in temperature positively affects refractive index of silica matrix at core–shell interface, , a simultaneous hyperchromic effect on absorption of AuNP as well as an increase in the particle temperature may occur (Supporting Information section S1.1).…”

Section: Results and Discussionmentioning

confidence: 99%

“…32 Therefore, an approach with additional intraband (Drude model) and interband model from previous literature was used to fit Otter's experimental data (Supporting Information S1.2). 33−36 Similarly, since the rise in temperature positively affects refractive index of silica matrix at core−shell interface, 37,38 a simultaneous hyperchromic effect on absorption of AuNP as well as an increase in the particle temperature may occur (Supporting Information section S1.1). The optical excitation of silica−AuNPs at a given pulse initially transfers energy to surface electrons (e − ) of the Au core followed by attenuation within a few hundreds of femtoseconds by e−e collision.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Optically Induced Structural Instability in Gold–Silica Nanostructures: A Case Study

Thomas¹,

Sreejith

Joshi

et al. 2016

J. Phys. Chem. C

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Optical excitation of plasmonic nanoparticles that generate heat or induce photoacoustic signals is gathering immense attention in biomedical applications such as imaging, photothermal therapy, and drug delivery. Generally, these nanoparticles are encompassed by a silica coating that enhances their overall activity and that imparts stability. Intuitively, only an extreme high pressure and temperature can lead to the morphological rupture of these heterogeneous composites; however, herein, we report a study which shows that these drastic structural defects can also be mimicked by simple optical pulse irradiation. This happens because of the heat and pressure waves generated in these hybrids. The structural differential expansion of constituent materials induces a thermal stress in the system which causes a structural instability and ultimately ruptures the coating. To demonstrate this phenomenon, a comprehensive theoretical and experimental study has been conducted on silica-coated gold nanoparticles, with diameter ca. 80 nm. The heat and pressure waves generated because of the irradiation initiate a crack in the silica coating and rupture the structure eventually. The mechanism of this phenomenon has also been elucidated in this paper via theoretical and experimental means.

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Section: Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Optically Induced Structural Instability in Gold–Silica Nanostructures: A Case Study

Thomas¹,

Sreejith

Joshi

et al. 2016

J. Phys. Chem. C

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“…The third relation derives the temperature dependence of refractive index of silica n silica whereby the refractive index of fused silica was reported to increase with temperature. However, the expected change in refractive index of silica near 1000 K is only up to1% [104,105]. Additionally, absorption cross section α abs of AuNP for 526 nm excitation increases when a temperature dependent variation of local refractive index of silica occurs.…”

Section: Temperature Dependence Of Variablesmentioning

confidence: 99%

“…Therefore, an approach with additional intra-band (Drude model) and inter-band model from previous literature were used to fit Otter's experimental data (section 2.2.2) [10,15,16,30]. Similarly, since the rise in temperature positively affects refractive index of silica matrix at core-shell interface [104,105], a simultaneous hyperchromic effect on absorption of AuNP as well as increase in the particle temperature may occur (section 2.2.1). The maximum temperature estimated using Equation Eq.…”

Section: Simulation and Analyticalmentioning

confidence: 99%

Modeling and analysis of post plasmonic effects in optically excited metal nanosystems

Thomas¹

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Correlating Heterogeneities in Support Fragmentation to Polymer Morphology in Metallocene‐Based Propylene Polymerization Catalysis

Dorresteijn,

Valadian,

et al. 2024

ChemCatChem

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In the field of olefin polymerization catalysis, metallocenes are heterogenized with methylaluminoxane onto silica supports to yield active catalysts. During olefin polymerization, these silica supports act as a framework to control the fragmentation stage, thereby influencing the final polymer product and preventing reactor fouling and fines formation. This study investigates the influence of different silica supports induced on the final polymer product. To study a broad range of silica supports from an industrial silica database, we utilize a hierarchical clustering method to cluster the supports based on their physical properties. From the clustering method, five supports representing the clusters and an industrial benchmark were analyzed at different polymerization stages using Focused Ion Beam Scanning Electron Microscopy (FIB‐SEM) and Micro‐computed Tomography (MicroCT). This combined FIB‐SEM/MicroCT methodology revealed differences in both fragmentation behavior and polymer morphologies based on structural features, including macropores, mesopores, spray‐dried shells, spray‐dried spheres, and denser shells. The heterogeneity and ideal fragmentation behavior was further assessed by calculating the replication factor of each support, indicating that silica materials containing macropores and spray‐dried shells have an almost ideal replication phenomenon. This multi‐scale analysis revealed new understanding of catalyst fragmentation for different supports.

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Theoretical and experimental investigations on the temperature dependence of the refractive index of amorphous silica

Cited by 18 publications

References 20 publications

Optically Induced Structural Instability in Gold–Silica Nanostructures: A Case Study

Optically Induced Structural Instability in Gold–Silica Nanostructures: A Case Study

Modeling and analysis of post plasmonic effects in optically excited metal nanosystems

Correlating Heterogeneities in Support Fragmentation to Polymer Morphology in Metallocene‐Based Propylene Polymerization Catalysis

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