The Experts below are selected from a list of 19635 Experts worldwide ranked by ideXlab platform
Jamie D. Phillips - One of the best experts on this subject based on the ideXlab platform.
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resolving Spectral Overlap issue of intermediate band solar cells using non uniform sub bandgap state filling
Progress in Photovoltaics, 2014Co-Authors: Albert Lin, Jamie D. PhillipsAbstract:Intermediate band solar cell provides novel alternative to multi-junction solar cell, but its efficiency is significantly degraded when Spectral Overlap exists between different absorption bands. Here, a scheme using non-uniform sub-bandgap state filling together with intermediate band transport is proposed to resolve the Spectral Overlap issue. On the basis of detailed balance calculation, Spectrally decoupled devices using low–high state filling is shown to achieve 52.8% conversion efficiency when 4eV Spectral Overlap is present between absorption coefficients of different bands, compared with baseline efficiency equal to 35.1% for conventional half-filled intermediate band devices. If a base material without intermediate band is added to the two section low–high state filling devices, the efficiency is further increased to 61.5%, which approaches efficiency of 63.2% for intermediate band devices with no Spectral Overlap and 63.8% for unconstrained triple-junction tandem cells. The junction thermalization loss associated with proposed new structures is shown to be equal to conventional half-filled intermediate band devices. Copyright © 2013 John Wiley & Sons, Ltd.
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Resolving Spectral Overlap issue of intermediate band solar cells using non‐uniform sub‐bandgap state filling
Progress in Photovoltaics: Research and Applications, 2013Co-Authors: Albert Lin, Jamie D. PhillipsAbstract:Intermediate band solar cell provides novel alternative to multi-junction solar cell, but its efficiency is significantly degraded when Spectral Overlap exists between different absorption bands. Here, a scheme using non-uniform sub-bandgap state filling together with intermediate band transport is proposed to resolve the Spectral Overlap issue. On the basis of detailed balance calculation, Spectrally decoupled devices using low–high state filling is shown to achieve 52.8% conversion efficiency when 4eV Spectral Overlap is present between absorption coefficients of different bands, compared with baseline efficiency equal to 35.1% for conventional half-filled intermediate band devices. If a base material without intermediate band is added to the two section low–high state filling devices, the efficiency is further increased to 61.5%, which approaches efficiency of 63.2% for intermediate band devices with no Spectral Overlap and 63.8% for unconstrained triple-junction tandem cells. The junction thermalization loss associated with proposed new structures is shown to be equal to conventional half-filled intermediate band devices. Copyright © 2013 John Wiley & Sons, Ltd.
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Decoupling Spectral Overlap of intermediate band solar cells using low-high state filling
2012 38th IEEE Photovoltaic Specialists Conference, 2012Co-Authors: Albert Lin, Jamie D. PhillipsAbstract:The high efficiency predicted for solar cells based on multi-photon processes relies on the assumption of optical transitions with non-Overlapping Spectral bands. Spectral Overlap reduces the conversion efficiency due to energy loss associated with improper usage of higher energy photons for lower energy optical transitions. In this study, device structures with non-uniform occupation of intermediate electronic states are proposed to reduce the dependence of conversion efficiency on Spectral Overlap. Solar cell conversion efficiencies are calculated for structures where absorption bands are spatially decoupled due to defined occupation of intermediate states. Conversion efficiencies for a two section and three section device with Spectral Overlap of 4 eV are determined to be 52.8 % and 61.5 %, respectively, and are significantly larger than the calculated efficiency of 35.1% for the case of a standard multi-photon cell with uniform half-filled intermediate states The Spectrally-decoupled device provides a means to achieve high theoretical efficiency independent of Spectral Overlap that approaches the detailed balance efficiency limit of 63.2 % for intermediate state devices without Spectral Overlap and 63.8 % for unconstrained triple—junction tandem cells.
Albert Lin - One of the best experts on this subject based on the ideXlab platform.
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resolving Spectral Overlap issue of intermediate band solar cells using non uniform sub bandgap state filling
Progress in Photovoltaics, 2014Co-Authors: Albert Lin, Jamie D. PhillipsAbstract:Intermediate band solar cell provides novel alternative to multi-junction solar cell, but its efficiency is significantly degraded when Spectral Overlap exists between different absorption bands. Here, a scheme using non-uniform sub-bandgap state filling together with intermediate band transport is proposed to resolve the Spectral Overlap issue. On the basis of detailed balance calculation, Spectrally decoupled devices using low–high state filling is shown to achieve 52.8% conversion efficiency when 4eV Spectral Overlap is present between absorption coefficients of different bands, compared with baseline efficiency equal to 35.1% for conventional half-filled intermediate band devices. If a base material without intermediate band is added to the two section low–high state filling devices, the efficiency is further increased to 61.5%, which approaches efficiency of 63.2% for intermediate band devices with no Spectral Overlap and 63.8% for unconstrained triple-junction tandem cells. The junction thermalization loss associated with proposed new structures is shown to be equal to conventional half-filled intermediate band devices. Copyright © 2013 John Wiley & Sons, Ltd.
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Resolving Spectral Overlap issue of intermediate band solar cells using non‐uniform sub‐bandgap state filling
Progress in Photovoltaics: Research and Applications, 2013Co-Authors: Albert Lin, Jamie D. PhillipsAbstract:Intermediate band solar cell provides novel alternative to multi-junction solar cell, but its efficiency is significantly degraded when Spectral Overlap exists between different absorption bands. Here, a scheme using non-uniform sub-bandgap state filling together with intermediate band transport is proposed to resolve the Spectral Overlap issue. On the basis of detailed balance calculation, Spectrally decoupled devices using low–high state filling is shown to achieve 52.8% conversion efficiency when 4eV Spectral Overlap is present between absorption coefficients of different bands, compared with baseline efficiency equal to 35.1% for conventional half-filled intermediate band devices. If a base material without intermediate band is added to the two section low–high state filling devices, the efficiency is further increased to 61.5%, which approaches efficiency of 63.2% for intermediate band devices with no Spectral Overlap and 63.8% for unconstrained triple-junction tandem cells. The junction thermalization loss associated with proposed new structures is shown to be equal to conventional half-filled intermediate band devices. Copyright © 2013 John Wiley & Sons, Ltd.
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Decoupling Spectral Overlap of intermediate band solar cells using low-high state filling
2012 38th IEEE Photovoltaic Specialists Conference, 2012Co-Authors: Albert Lin, Jamie D. PhillipsAbstract:The high efficiency predicted for solar cells based on multi-photon processes relies on the assumption of optical transitions with non-Overlapping Spectral bands. Spectral Overlap reduces the conversion efficiency due to energy loss associated with improper usage of higher energy photons for lower energy optical transitions. In this study, device structures with non-uniform occupation of intermediate electronic states are proposed to reduce the dependence of conversion efficiency on Spectral Overlap. Solar cell conversion efficiencies are calculated for structures where absorption bands are spatially decoupled due to defined occupation of intermediate states. Conversion efficiencies for a two section and three section device with Spectral Overlap of 4 eV are determined to be 52.8 % and 61.5 %, respectively, and are significantly larger than the calculated efficiency of 35.1% for the case of a standard multi-photon cell with uniform half-filled intermediate states The Spectrally-decoupled device provides a means to achieve high theoretical efficiency independent of Spectral Overlap that approaches the detailed balance efficiency limit of 63.2 % for intermediate state devices without Spectral Overlap and 63.8 % for unconstrained triple—junction tandem cells.
Chun-kit Chan - One of the best experts on this subject based on the ideXlab platform.
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Channel interference study and power ratio optimization on two optical Nyquist-PM-QPSK signals with Spectral Overlap.
Optics express, 2019Co-Authors: Shuang Gao, Yang Qiu, Chun-kit ChanAbstract:Recent signal processing of optical signals has involved possible Overlapping of the spectra from the adjacent optical channels for channel multiplexing and improving system throughput. However, the incurred channel interference performance has not yet been carefully characterized. In this paper, we carry out simulations and experiments to investigate various system parameters that determine such adjacent channel interference performance and further optimize the channel power ratio when two optical channels, each carrying a Nyquist shaped and polarization multiplexed quadrature phase-shift keying (Nyquist-PM-QPSK) signal, are being multiplexed with optical Spectral Overlap. With a properly designed successive interference cancellation (SIC) algorithm, both channels can be successfully separated and decoded individually. The OSNR penalties due to possible time offset, polarization rotation, and frequency offset between the two adjacent optical channels are investigated. The power ratio between the two adjacent optical channels are further optimized with respect to the OSNR penalties.
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Spectral Overlap of two bandwidth variable Nyquist-WDM signals to resolve wavelength conflict in elastic optical networks
2016Co-Authors: Shuang Gao, Lingchen Huang, Chun-kit ChanAbstract:We investigate a simple Spectral Overlap method to resolve the wavelength conflict for two independent bandwidth variable Nyquist-WDM signals by relative power control. Individual signals can be separated and recovered by digital signal processing.
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Wavelength conflict resolution by Spectral Overlap of two Nyquist-WDM signals
CLEO: 2015, 2015Co-Authors: Lingchen Huang, Shuang Gao, Chun-kit ChanAbstract:Two Nyquist-WDM signals arc Spectrally Overlapped to resolve the possible wavelength conflict in network routing. Recovery of individual signals is realized by digital signal processing techniques and has been experimentally demonstrated and characterized.
Andrzej Ke¸dziorski - One of the best experts on this subject based on the ideXlab platform.
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Efficiency of the energy transfer in lanthanide-organic chelates; Spectral Overlap integral
Journal of Luminescence, 2010Co-Authors: Lidia Smentek, Andrzej Ke¸dziorskiAbstract:Abstract The present work is devoted to the evaluation of the efficiency of the sensitized luminescence of the lanthanide complexes. In particular the dependence of the quantum yield of the luminescence on the physical factors that determine the Spectral Overlap integral is analyzed in detail. The calculations are based on the model of the evaluation of the Spectral Overlap integral proposed by Malta. It is shown that the theoretical trend in the change of the quantum yield reproduces the general properties of the experimental behavior observed in particular for Tb 3+ complexes.
Shuang Gao - One of the best experts on this subject based on the ideXlab platform.
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Channel interference study and power ratio optimization on two optical Nyquist-PM-QPSK signals with Spectral Overlap.
Optics express, 2019Co-Authors: Shuang Gao, Yang Qiu, Chun-kit ChanAbstract:Recent signal processing of optical signals has involved possible Overlapping of the spectra from the adjacent optical channels for channel multiplexing and improving system throughput. However, the incurred channel interference performance has not yet been carefully characterized. In this paper, we carry out simulations and experiments to investigate various system parameters that determine such adjacent channel interference performance and further optimize the channel power ratio when two optical channels, each carrying a Nyquist shaped and polarization multiplexed quadrature phase-shift keying (Nyquist-PM-QPSK) signal, are being multiplexed with optical Spectral Overlap. With a properly designed successive interference cancellation (SIC) algorithm, both channels can be successfully separated and decoded individually. The OSNR penalties due to possible time offset, polarization rotation, and frequency offset between the two adjacent optical channels are investigated. The power ratio between the two adjacent optical channels are further optimized with respect to the OSNR penalties.
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Spectral Overlap of two bandwidth variable Nyquist-WDM signals to resolve wavelength conflict in elastic optical networks
2016Co-Authors: Shuang Gao, Lingchen Huang, Chun-kit ChanAbstract:We investigate a simple Spectral Overlap method to resolve the wavelength conflict for two independent bandwidth variable Nyquist-WDM signals by relative power control. Individual signals can be separated and recovered by digital signal processing.
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Wavelength conflict resolution by Spectral Overlap of two Nyquist-WDM signals
CLEO: 2015, 2015Co-Authors: Lingchen Huang, Shuang Gao, Chun-kit ChanAbstract:Two Nyquist-WDM signals arc Spectrally Overlapped to resolve the possible wavelength conflict in network routing. Recovery of individual signals is realized by digital signal processing techniques and has been experimentally demonstrated and characterized.
