The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Manfred Eich - One of the best experts on this subject based on the ideXlab platform.
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transparency induced in opals via nanometer thick Conformal Coating
Scientific Reports, 2019Co-Authors: Guoliang Shang, Kaline Pagnan Furlan, Robert Zierold, Robert H Blick, Rolf Jansen, Alexander Yu Petrov, Manfred EichAbstract:Self-assembled periodic structures out of monodisperse spherical particles, so-called opals, are a versatile approach to obtain 3D photonic crystals. We show that a thin Conformal Coating of only several nanometers can completely alter the reflection properties of such an opal. Specifically, a Coating with a refractive index larger than that of the spherical particles can eliminate the first photonic band gap of opals. To explain this non-intuitive effect, where a nm-scaled Coating results in a drastic change of optical properties at wavelengths a hundred times bigger, we split the permittivity distribution of the opal into a lattice function convoluted with that of core-shell particles as a motif. In reciprocal space, the Bragg peaks that define the first Brillouin zone can be eliminated if the motif function, which is multiplied, assumes zero at the Bragg peak positions. Therefore, we designed a non-monotonic refractive index distribution from the center of the particle through the shell into the background and adjusted the Coating thickness. The theory is supported by simulations and experiments that a nanometer thin TiO2 Coating via atomic layer deposition (ALD) on synthetic opals made from polystyrene particles induces nearly full transparency at a wavelength range where the uncoated opal strongly reflects. This effect paves the way for sensing applications such as monitoring the thicknesses growth in ALD in-situ and in real time as well as measuring a refractive index change without spectral interrogation.
Alexander Yu Petrov - One of the best experts on this subject based on the ideXlab platform.
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transparency induced in opals via nanometer thick Conformal Coating
Scientific Reports, 2019Co-Authors: Guoliang Shang, Kaline Pagnan Furlan, Robert Zierold, Robert H Blick, Rolf Jansen, Alexander Yu Petrov, Manfred EichAbstract:Self-assembled periodic structures out of monodisperse spherical particles, so-called opals, are a versatile approach to obtain 3D photonic crystals. We show that a thin Conformal Coating of only several nanometers can completely alter the reflection properties of such an opal. Specifically, a Coating with a refractive index larger than that of the spherical particles can eliminate the first photonic band gap of opals. To explain this non-intuitive effect, where a nm-scaled Coating results in a drastic change of optical properties at wavelengths a hundred times bigger, we split the permittivity distribution of the opal into a lattice function convoluted with that of core-shell particles as a motif. In reciprocal space, the Bragg peaks that define the first Brillouin zone can be eliminated if the motif function, which is multiplied, assumes zero at the Bragg peak positions. Therefore, we designed a non-monotonic refractive index distribution from the center of the particle through the shell into the background and adjusted the Coating thickness. The theory is supported by simulations and experiments that a nanometer thin TiO2 Coating via atomic layer deposition (ALD) on synthetic opals made from polystyrene particles induces nearly full transparency at a wavelength range where the uncoated opal strongly reflects. This effect paves the way for sensing applications such as monitoring the thicknesses growth in ALD in-situ and in real time as well as measuring a refractive index change without spectral interrogation.
Kaline Pagnan Furlan - One of the best experts on this subject based on the ideXlab platform.
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transparency induced in opals via nanometer thick Conformal Coating
Scientific Reports, 2019Co-Authors: Guoliang Shang, Kaline Pagnan Furlan, Robert Zierold, Robert H Blick, Rolf Jansen, Alexander Yu Petrov, Manfred EichAbstract:Self-assembled periodic structures out of monodisperse spherical particles, so-called opals, are a versatile approach to obtain 3D photonic crystals. We show that a thin Conformal Coating of only several nanometers can completely alter the reflection properties of such an opal. Specifically, a Coating with a refractive index larger than that of the spherical particles can eliminate the first photonic band gap of opals. To explain this non-intuitive effect, where a nm-scaled Coating results in a drastic change of optical properties at wavelengths a hundred times bigger, we split the permittivity distribution of the opal into a lattice function convoluted with that of core-shell particles as a motif. In reciprocal space, the Bragg peaks that define the first Brillouin zone can be eliminated if the motif function, which is multiplied, assumes zero at the Bragg peak positions. Therefore, we designed a non-monotonic refractive index distribution from the center of the particle through the shell into the background and adjusted the Coating thickness. The theory is supported by simulations and experiments that a nanometer thin TiO2 Coating via atomic layer deposition (ALD) on synthetic opals made from polystyrene particles induces nearly full transparency at a wavelength range where the uncoated opal strongly reflects. This effect paves the way for sensing applications such as monitoring the thicknesses growth in ALD in-situ and in real time as well as measuring a refractive index change without spectral interrogation.
Jun Yeon Hwang - One of the best experts on this subject based on the ideXlab platform.
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nano carbon Conformal Coating strategy for enhanced photoelectrochemical responses and long term stability of zno quantum dots
Nano Energy, 2015Co-Authors: Jung Kyu Kim, Sukang Bae, Wanjung Kim, Myung Jin Jeong, Sang Hyun Lee, Changlyoul Lee, Won Kook Choi, Jun Yeon HwangAbstract:Abstract A Conformal Coating strategy with nanocarbon to enhance photoelectrochemical responses and the long-term stability of ZnO quantum dots is described. Strong anchoring bonds between a ZnO core and nanocarbon shell ameliorate the poor electrochemical stability of ZnO (such as photocorrosion) in liquid electrolyte. The conjugation of the graphene QD and C60 to the ZnO QDs leads to 71% and 99% quenching of the UV photoluminescence (PL) emission, respectively. Also, the decay time of the nanocomposites at UV wavelengths measured much faster than that for the reference of bare ZnO QDs. The moderate energy states and good charge conductance of the nanocarbons result in ultrafast charge transport from the ZnO core to the nanocarbon shell. Thereby, the ZnO core–nanocarbon shell quantum dots shows significantly improved light harvesting performance. The PEC cell test for water oxidation and conventional degradation test using organic dyes exhibited that the photoelectrochemical activities could be significantly improved. At 1.23 V (vs. RHE) in pH 6.9 electrolyte, 6 times enhanced photocurrent density was achieved by the Conformal Coating with C60 (0.235 mA/cm2 for ZnO–C60 photoanodes). In particular, the strong Zn–O–C bond structures on the ZnO surface prevented photoinduced holes from being consumed by the photocorrosion reaction of ZnO, thereby improving long-term stability.
Guoliang Shang - One of the best experts on this subject based on the ideXlab platform.
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transparency induced in opals via nanometer thick Conformal Coating
Scientific Reports, 2019Co-Authors: Guoliang Shang, Kaline Pagnan Furlan, Robert Zierold, Robert H Blick, Rolf Jansen, Alexander Yu Petrov, Manfred EichAbstract:Self-assembled periodic structures out of monodisperse spherical particles, so-called opals, are a versatile approach to obtain 3D photonic crystals. We show that a thin Conformal Coating of only several nanometers can completely alter the reflection properties of such an opal. Specifically, a Coating with a refractive index larger than that of the spherical particles can eliminate the first photonic band gap of opals. To explain this non-intuitive effect, where a nm-scaled Coating results in a drastic change of optical properties at wavelengths a hundred times bigger, we split the permittivity distribution of the opal into a lattice function convoluted with that of core-shell particles as a motif. In reciprocal space, the Bragg peaks that define the first Brillouin zone can be eliminated if the motif function, which is multiplied, assumes zero at the Bragg peak positions. Therefore, we designed a non-monotonic refractive index distribution from the center of the particle through the shell into the background and adjusted the Coating thickness. The theory is supported by simulations and experiments that a nanometer thin TiO2 Coating via atomic layer deposition (ALD) on synthetic opals made from polystyrene particles induces nearly full transparency at a wavelength range where the uncoated opal strongly reflects. This effect paves the way for sensing applications such as monitoring the thicknesses growth in ALD in-situ and in real time as well as measuring a refractive index change without spectral interrogation.