Papers - NISHIOKA Kensuke
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Evaluating the Output of a Car-Mounted Photovoltaic Module under Driving Conditions Reviewed
Ota Y., Araki K., Nagaoka A., Nishioka K.
IEEE Journal of Photovoltaics 11 ( 5 ) 1299 - 1304 2021.9
Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE Journal of Photovoltaics
In this article, we measured and estimated the outputs of car-mounted PV panels under actual driving conditions and different effective shading angles. On a sunny day, the performance ratio (PR) decreased to 0.99, despite the decrease in module temperature caused by the increased wind speed when driving. The PR decreased because of the effect of partial shading over the PV module. Public infrastructure could have led to dynamic partial shading passing across the PV module at high speeds. Furthermore, the effective shading angle being close to the sun's altitude could also have led to static partial shading. In contrast, on an overcast day the PR value was almost the same ($>$1) under both driving and parking conditions; this was because of the low module temperature and the spectrum effect.
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Wai S.H., Ota Y., Nishioka K.
International Journal of Hydrogen Energy 46 ( 53 ) 26801 - 26808 2021.8
Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Hydrogen Energy
Synthetic methane is a major energy carrier having high energy density and can potentially replace fossil fuels. In this study, a solar-to-gas conversion system was developed using CO2 and solar-based hydrogen to meet the present energy demands. However, high reaction temperature induced by the inlet reactant gases can affect catalyst performance and cost of investment. Thus, we investigated power consumption of the reactor operating temperature for the system. The influence of hydrogen generation rates (GRH2) on the Sabatier reaction was analyzed, and the concentration of methane and total power consumption of the methanation system was highlighted. The highest methane concentrations were observed at 0.337 and 0.449 NL/min of GRH2. Subsequently, high methane composition (98.4%) was observed at 220 °C and 0.449 NL/min of GRH2. Therefore, methanation system with solar-based hydrogen can effectively distribute synthetic methane to the gas grid.
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Nagaoka A., Ota Y., Sakai K., Araki K., Matsuo H., Kadota N., Maeda K., Nakajima A., Nishioka K.
Renewable Energy 174 147 - 156 2021.8
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Renewable Energy
The concept of zero-energy building (ZEB) has attracted global attention in recent years as it involves offsetting the primary energy usage of a building on an annual base by the energy generated from renewable resources. The performance of wall-mounted photovoltaics (PV) for building applications has great potential for ZEB. In this study, we compared wall-mounted and common roof-mounted PV systems using a combination of experimental and theoretical studies. The wall-mounted PV system exhibited an unusual performance behavior depending on the season. Winter is a suitable season for energy production from the wall-mounted PV system because of the low solar altitude and resulting lower incident angle of the sun. However, the performance ratio (PR) had twin peaks throughout the day that could not be explained by the classical model that uses irradiance and temperature variation. In summer, there was less irradiance on the vertical wall and the PR had triple peaks that were also hard to explain using the conventional model. We established a detailed output power model of the wall-mounted PV using spectrum variation on a vertical plane. Our approach is the development of spectrum model that can be applied to all-climate and computed the performance variation according to the sun's orientation and incident angle. Our model quantitatively explains unique seasonal and daily efficiency variations for the wall-mounted PV system (twin peaks in winter and triple peaks in summer). Our validated model can be utilized to map a suitable location for a wall-mounted PV system.
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Nagaoka A., Yoshino K., Masuda T., Sparks T.D., Scarpulla M.A., Nishioka K.
Journal of Materials Chemistry A 9 ( 28 ) 15595 - 15604 2021.7
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Materials Chemistry A
Thermoelectrics (TEs) are an important class of technology that harvest electric power directly from heat sources. When designing both high performance and environmentally friendly TE materials, the pseudo-cubic structure has great theoretical potential to maximize the dimensionless figure of meritZT. The TE multinary single crystal with a pseudo-cubic structure paves a new path toward manipulating valley degeneracy and anisotropy with low thermal conductivity caused by short-range lattice distortion. Here, we report a record highZT= 1.6 around 800 K realized in a totally environmentally benign p-type Na-doped Cu2ZnSnS4(CZTS) single crystal. The exceptional performance comes from a high power factor while maintaining intrinsically low thermal conductivity. The combination of the pseudo-cubic structure and intrinsic properties of the CZTS single crystal takes advantage of simple material tuning without complex techniques.
DOI： 10.1039/d1ta02978a
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Importance of Developing Photovoltaics-Powered Vehicles Reviewed
Masafumi Yamaguchi, Taizo Masuda, Takashi Nakado, Yusuke Zushi, Kenji Araki, Tatsuya Takamoto, Kenichi Okumura, Akinori Satou, Kazumi Yamada, Yasuyuki Ota, Kensuke Nishioka, Tsutomu Tanimoto, Kyotaro Nakamura, Ryo Ozaki, Nobuaki Kojima, Yoshio Ohshita
Energy and Power Engineering 13 147 - 162 2021.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Physics and Chemistry of Solids
Chimney-ladder sulfide Sr9Ti8S24 (STS) has potential as a thermoelectric (TE) material because of its intrinsic low thermal conductivity. We studied the growth of a polycrystalline STS sample and its fundamental TE properties. The resistivity of n-type polycrystalline STS can be described as thermal activation and the potential barrier at grain boundary. Regarding the TE properties, n-type STS polycrystalline samples exhibit a low thermal conductivity <1 W/mK between 323 and 673 K caused by a large unit cell with an axis = 12.15 Å, c axis = 42.32 Å, and Umklapp scattering. Consequently, the figure of merit for the STS sample reaches 3.0 × 10−4 at 673 K.
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Phase diagram of the Ag2SnS3–ZnS pseudobinary system for Ag2ZnSnS4 crystal growth Reviewed
Nagaoka A., Yoshino K., Kakimoto K., Nishioka K.
Journal of Crystal Growth 555 125967 2021.2
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Crystal Growth
The phase equilibrium of the Ag SnS –ZnS pseudobinary system for the growth of Ag ZnSnS (AZTS) crystals was investigated using the equilibration-quenching technique. The growth mechanism of AZTS follows the peritectic reaction liquid phase + ZnS phase ↔ AZTS phase, which occurs at a composition of ~20 mol% ZnS and a temperature of approximately 700 °C. The AZTS polycrystalline sample was obtained from the stoichiometric melt growth. The kesterite structure of the AZTS sample without secondary phases was identified by a combination of X-ray diffraction and Raman spectroscopy measurements. The electron carrier concentration and conductivity, determined by the Hall effect measurement, were (3.0–6.3) × 10 cm and (5.6–9.2) × 10 S/cm, respectively. The slightly Zn-rich and S-poor composition led to n-type conduction in the AZTS because of the dominant Zn antisites on Ag (Zn ) and S vacancy (V ) defects. Therefore, this study can make a significant contribution to the research and application of AZTS materials. 2 3 2 4 Ag S 15 −3 −4
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Development of High-Efficiency Solar Cell Modules for Photovoltaic-Powered Vehicles Reviewed
Yamaguchi M., Ozaki R., Nakamura K., Lee K.H., Kojima N., Ohshita Y., Masuda T., Okumura K., Satou A., Nakado T., Yamada K., Araki K., Ota Y., Nishioka K., Takamoto T., Zushi Y., Tanimoto T., Thiel C., Tsakalidis A., Jäger-Waldau A.
Solar RRL 2021
Language：English Publishing type：Research paper (scientific journal) Publisher：Solar RRL
Photovoltaic (PV)-powered vehicles are expected to play a critical role in a future carbon neutral society because it has been reported that the onboard PVs have great ability to reduce CO2 emission from the transport sector. Although the demonstration car with a III−V-based solar cell module has shown the PV-powered driving range of 36.6 km day−1 at solar irradiance of 6.2 kWh m−2 day−1, practical driving ranges of PV-powered vehicles are shown to be lower than estimated values due to some losses such as nonradiative recombination and resistance losses of solar cell modules under sunshine condition. This article presents analytical results for the effects of illumination intensity properties of various solar cell modules on the PV-powered driving range to develop highly efficient solar cell modules for vehicle-integrated applications. The analysis shows that improvements in shunt resistance and saturation current density of solar cell modules are necessary to improve illumination intensity properties of solar cell modules under low intensity sunshine condition. The calculations show that the III−V-based 3-junction solar cell modules with an efficiency of more than 30% have a potential PV-powered driving range of 30 km/day average and more than 50 km day−1 on a clear day.
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Chalcostibite Single-Crystal CuSbS<sub>2</sub> as High-Performance Thermoelectric Material Reviewed
Nagaoka Akira, Takeuchi Manato, Shigeeda Yusuke, Kamimizutaru Koki, Yoshino Kenji, Nishioka Kensuke
MATERIALS TRANSACTIONS 61 2407 - 2411 2020.12
Language：English Publishing type：Research paper (scientific journal) Publisher：公益社団法人 日本金属学会
Chalcostibite CuSbS<sub>2</sub> has attracted attention as an environmentally friendly material in thermoelectric (TE) field. Our investigations into the TE properties of high-quality p-type CuSbS<sub>2</sub> single crystals revealed that they exhibit a uniquely low thermal conductivity caused by the active lone-pair electrons in Sb<sup>3+</sup> ions. The electrical conductivity was improved by the high density of shallow acceptor Cu vacancies and the absence of potential barriers to carrier transport. Consequently, the figure of merit for the Cu-poor CuSbS<sub>2</sub> single crystal reached 0.5 at 700 K, which is 25 times higher than that of the reported polycrystalline sample.
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Hishikawa Y., Higa M., Takenouchi T., Ueda Y., Nishioka K., Kobayashi T., Minemoto T., Taniguchi H., Wakabayashi H., Yoshita M.
Solar Energy 211 82 - 89 2020.11
Language：English Publishing type：Research paper (scientific journal) Publisher：Solar Energy
© 2020 Highly precise outdoor current-voltage (I-V) curve measurement of crystalline silicon photovoltaic (PV) modules has been achieved, by monitoring the solar irradiance with a PV module irradiance sensor (PVMS), measuring the curves in 0.2–0.5 s, and filtering out the data affected by spatial nonuniformity of irradiance. The I-V curves were corrected for temperature by using a recently developed translation formula. Good reproducibility in the short circuit current ISC, open circuit voltage VOC, and maximum power Pmax measurements was confirmed, based on repeated measurements for one week. Small values of relative standard deviation σ, i.e., 0.1–0.23% and 0.24–0.42% for the ISC/GPVMS and Pmax/GPVMS, respectively, were confirmed even on partially sunny days and cloudy days when the solar irradiance is very unstable. Here, GPVMS denotes the irradiance measured by using a PVMS. The values of σ for various kinds of commercial crystalline silicon modules, including the p-type BSF, p-type PERC, n-type backside contact and silicon heterojunction, were also investigated in longer periods including different seasons of the year, which were 0.1–0.5% and 0.5–1.3% in the irradiance ranges of 0.9–1.1 kW/m2 and 0.3–0.5 kW/m2, respectively. The results have demonstrated that precise outdoor I-V curve measurements are possible in wide range of irradiance under various weather conditions. They are useful for improving the throughput and accuracy of onsite I-V measurements in operation and maintenance. Possible sources of residual measurement error and methods to further improve the precision are also discussed.
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How did the knowledge of CPV contribute to the standardization activity of VIPV? Reviewed
Araki K., Ji L., Kelly G., van der Ham A., Agudo E., Antón I., Baudrit M., Carr A., Herrero R., Kurtz S., Liu Z., Pravettoni M., Ota Y., Tobita H., Yoon S., Yoshita M., Yamaguchi M., Nishioka K.
AIP Conference Proceedings 2298 2020.11
Language：English Publishing type：Research paper (scientific journal) Publisher：AIP Conference Proceedings
The standardization of VIPV (Vehicle-integrated photovoltaic) has been driven by the international discussion among scientists and engineers, from photovoltaic research, photovoltaic industries, automobile and other industries, and testing laboratories. Since the VIPV is not flat and fixed installation, as well as a wide variety of designs, the knowledge of CPV (Concentrator Photovoltaic) technology, has been useful for developing testing technologies. This paper took two examples in the performance testing and the test for the tolerance for the partial/dynamic shading, utilizing various techniques exclusively used in CPV technologies.
DOI： 10.1063/5.0032997
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Araki K., Ota Y., Saiki H., Tawa H., Nishioka K., Sato D., Yamaguchi M.
AIP Conference Proceedings 2298 2020.11
Language：English Publishing type：Research paper (scientific journal) Publisher：AIP Conference Proceedings
The performance of CPV is sensitive to the spectrum change. Several previous works have been published on the sensitivity of multi-junction cells to airmass variations as well as works on band gap tuning and optimization of multi-junction stacks under concentrated radiation in various locations. Such a variety of atmospheric conditions, airmass as well as climate (quality of direct sunlight) are dynamic and cannot be controlled by the product design. All we can do is to customize the design by locations (not capable of dynamic variation) or inventing a robust device configuration against a dynamic change of atmospheric conditions (also effective to regional variation). Enhancing a luminescent coupling is useful to suppress the spectrum mismatching loss inherent to outdoor CPV installation. The configuration of the solar cell with 100 % of the recycling of the surplus photon energy for compensating spectrum mismatching is called an SMJ solar cell (super-multi-junction solar cell). The advantage of the SMJ solar cells in non-concentrating fixed sloped angle installation was intensively analyzed in the previous works. However, that of CPV was only investigated under the combination of the worst-case atmospheric parameter distributions, and not under the realistic spectrum variations, so that the calculation result was too extreme. This paper intended to fill the missing stone, by updating a previous result on CPV modeled under the combination of the worst-case variations of atmospheric conditions in the worst locations for CPV, by the realistic fluctuation pattern of meteorological parameters and climate using the intensive analysis that was done to the non-concentration installation (fixed installation). The SMJ was also confirmed valid to CPV under the dynamic fluctuation of the direct solar resources. Different from the non-concentrating operation, the normal CPV was found raising annual average outdoor efficiency under realistic atmospheric conditions simulated by the regional states in Miyazaki, Japan, up to six-junctions. This analysis also implies the bandgap design guideline for the robustness of the spectrum variation, trying to place the bandgap energy of the some of the sub-cells close to the water-absorption band (1.3 eV, 1.1 eV, and 0.89 eV).
DOI： 10.1063/5.0032996
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Nagaoka A., Nishioka K., Yoshino K., Kuciauskas D., Scarpulla M.A.
Journal of Electronic Materials 2020.8
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Electronic Materials
© 2020, The Minerals, Metals & Materials Society. The photovoltaic performance of CdTe solar cells is mainly limited by low doping and short minority carrier lifetime. Group-V element doping and Se-alloying have a significant impact on tuning these fundamental CdTe properties. In this paper, we report the growth of p-type As-doped, Cd-rich CdTe1−xSex single crystals using metallic Cd as the solvent in the traveling-heater method. The structural and electrical properties of CdTe1−xSex are examined for different Se concentrations. CdTe1−xSex single crystals (0 ≤ x ≤ 0.5) with zincblende structure indicate homogeneous composition. The 1017 cm−3 As-doping activation efficiency can be maintained at close to 50% for x ≤ 0.2. Se alloying leads to bulk minority carrier lifetime exceeding 30 ns for samples doped near 1017 cm−3. These results help us to overcome the current roadblocks in device performance.
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Wai S., Ota Y., Sugiyama M., Nishioka K.
Applied Sciences (Switzerland) 10 ( 9 ) 3144-1 - 3144-11 2020.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Sciences (Switzerland)
© 2020 by the authors. Power to gas (P2G) process chains have tremendous potential to enhance energy systems because of the capability of solar energy to convert solar radiation into electrical energy as well as the increasing use of specific gases as a means to store the resulting energy. Utilizing sunlight, photovoltaic systems are capable of producing useful gases such as hydrogen (H2) and methane (CH4). These gases are utilized in gas grids, transportation, and heavy industry. In employing a sunlight-derived gas, H2 production, by water disbanding, needs to be cost-effective with tremendous adaptability. New powerful solar to gas conversion system modules have been successfully carried out in the University of Miyazaki, Japan. These systems contain DC/DC converters and electrolyzer sets linked in parallel with efficient three concentrator photovoltaics (CPV). The performance of the solar to methane conversion process and power consumption analysis will be the focus of the current research. Efficiencies of 97.6% of CO2 to CH4 conversion and 13.8% for solar to methane on a clear sunny day were obtained by utilizing highly efficient CPV modules connected with multiple converters, electrochemical cells, and reactors fixed with Ni-based catalysts.
DOI： 10.3390/app10093144
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Nagaoka A., Nishioka K., Yoshino K., Katsube R., Nose Y., Masuda T., Scarpulla M.A.
Applied Physics Letters 116 ( 13 ) 132102-1 - 132102-5 2020.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Physics Letters
© 2020 Author(s). Acceptor doping CdTe with group-V elements is promising for increasing the power conversion efficiency of CdTe photovoltaic devices via an increased hole concentration and open circuit voltage (VOC). In past work, we have investigated doping with As in Cd-rich CdTe single crystals grown using the Cd-solvent traveling heater method we have developed. In this study, we compare the doping parameters and stability of hole concentration in the light and dark for P, As, and Sb dopants in crystals cooled very slowly from the growth temperature to approximate thermal equilibrium. In contrast to older reports of a high acceptor ionization energy for Sb, our temperature dependent Hall effect experiments reveal an acceptor ionization energy slightly above 90 meV for Sb doping in the mid 1016 cm-3 range. Room temperature hole concentrations above 1016 cm-3 are observed for P, As, and Sb with each dopant type exhibiting only small changes in hole concentrations over 2 years' time at room temperature. Crystals doped with P, As, or Sb exhibit increased conductivity after above-gap illumination, which decays over periods of minutes to hours depending on temperature. Analysis of the photoconductivity decay reveals a barrier attributed to hole capture of 190-280 meV for the series P, As, and Sb.
DOI： 10.1063/5.0004883
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The outdoor field test and energy yield model of the four-terminal on si tandem PV module Reviewed
Araki K., Tawa H., Saiki H., Ota Y., Nishioka K., Yamaguchi M.
Applied Sciences (Switzerland) 10 ( 7 ) 2529-1 - 2529-17 2020.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Sciences (Switzerland)
© 2020 by the authors. The outdoor field test of the 4-terminal on Si tandem photovoltaic module (specifically, InGaP/GaAs on Si) was investigated and a performance model, considering spectrum change affected by fluctuation of atmospheric parameters, was developed and validated. The 4-terminal on Si tandem photovoltaic module had about 40% advantage in seasonal performance loss compared with standard InGaP/GaAs/InGaAs 2-terminal tandem photovoltaic module. This advantage increases (subarctic zone < temperate zone < subtropical zone). The developed and validated model used an all-climate spectrum model and considered fluctuation of atmospheric parameters. It can be applied every type of on-Si tandem solar cells.
DOI： 10.3390/app10072529
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Tawa H., Saiki H., Ota Y., Araki K., Takamoto T., Nishioka K.
Applied Sciences (Switzerland) 10 ( 2 ) 703-1 - 703-15 2020.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Sciences (Switzerland)
© 2020 by the authors. Because semiconductors absorb wavelengths dependent on the light absorption coefficient, photovoltaic (PV) energy output is affected by the solar spectrum. Therefore, it is necessary to consider the solar spectrum for highly accurate PV output estimation. Bird's model has been used as a general spectral model. However, atmospheric parameters such as aerosol optical depth and precipitable water have a constant value in the model that only applies to clear days. In this study, atmospheric parameters were extracted using the Bird's spectrum model from the measured global spectrum and the seasonal fluctuation of atmospheric parameters was examined. We propose an overcast spectrum model and calculate the all-weather solar spectrum from clear to overcast sky through linear combination. Three types of PV modules (fixed Si, two-axis tracking Si, and fixed InGaP/GaAs/InGaAs triple-junction solar cells) were installed at the University of Miyazaki. The estimated performance ratio (PR), which takes into account incident angle and spectral variations, was consistent with the measured PR. Finally, the energy yield of various PVs installed across Japan was successfully estimated.
DOI： 10.3390/app10020703
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Chantana J., Imai Y., Kawano Y., Hishikawa Y., Nishioka K., Minemoto T.
Renewable Energy 145 1317 - 1324 2020.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Renewable Energy
© 2019 Elsevier Ltd Spectral grain and loss (spectral gain&loss) of several-type PV technologies (amorphous silicon (a-Si), perovskite (perov), CdTe, CuInSe2 (CIS), multi-crystalline silicon (mc-Si), single-crystalline silicon back-contact (BC), single-crystalline silicon (sc-Si), and heterostructure-with-intrinsic-thin-layer (HIT)) was investigated in different places (Kusatsu city, Tsukuba city, and Miyazaki city in Japan) in a year. Spectral gain&loss is defined as a ratio of short-circuit current (ISC) corrected by solar irradiance (Irr) for PV module at an average photon energy (APE) to its ISC under standard test condition. The blue-rich spectra with APE over 1.88 eV yield spectral gain (spectral gain&loss over 1) for CdTe, perov, and a-Si PV technologies owing to large band-gap energy (Eg) values of 1.47, 1.60, and 1.80 eV, respectively. On the other hand, red-rich spectra with APE below 1.88 eV lead to spectral gain for CIS, mc-Si, BC, sc-Si, and HIT PV technologies with smaller Eg values of 1.21, 1.13, 1.17, 1.16, and 1.09 eV, respectively. Moreover, since average APE values in Kusatsu city, Tsukuba city, and Miyazaki city are 1.931, 1.900, and 1.899 eV, respectively, a-Si, perov, and CdTe PV technologies are suitable in term of spectral response. The spectral gain&loss of PV modules compared with sc-Si PV module is moreover discussed.
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Araki K., Ota Y., Saiki H., Tawa H., Nishioka K., Yamaguchi M.
Applied Sciences (Switzerland) 9 ( 21 ) 4598-1 - 4598-21 2019.11
Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Sciences (Switzerland)
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. The highest-efficiency solar cell in the efficiency race does not always give the best annual energy yield in real world solar conditions because the spectrum is always changing. The study of radiative coupling of concentrator solar cells implies that efficiency could increase by recycling the radiative recombination generated by the surplus current in the upper junction. Such a configuration is called a super-multi-junction cell. We expand the model in the concentrator solar cell to a non-concentrating installation. It is shown that this super-multi-junction cell configuration is robust and can keep maximum potential efficiency (50% in realistic spectrum fluctuation) for up to 10 junctions. The super-multi-junction cell is also robust in the bandgap engineering of each junction. Therefore, a future multi-junction may not be required for tuning the bandgap to match the standard solar spectrum, as well as relying upon artificial technologies such as epitaxial lift-off (ELO), wafer-bonding, mechanical-stacking, and reverse-growth, but merely uses upright and lattice-matching growth technologies. We present two challenging techniques; one is the optical cap layer that may be the directional photon coupling layer in the application of the photonics technologies, and another is the high-quality epitaxial growth with almost 100% radiative efficiency.
DOI： 10.3390/app9214598
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Reduction of Soiling on Photovoltaic Modules by a Tracker System with Downward-Facing Standby State Reviewed
Ota Y., Nagaoka A., Nishioka K.
International Journal of Photoenergy 2019 1296065-1 - 1296065-8 2019.10
Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Photoenergy
© 2019 Yasuyuki Ota et al. The radiation received by solar cells within photovoltaic modules is lower than that arriving at the module surface. One of the causes of this energy loss is soiling of the module surface. Therefore, the influence of dust adhesion on photovoltaic modules must be studied. In this study, we prepared two tracker systems: a new system and a typical system. During the night, the former can switch to a downward-facing standby state, while the latter assumes an upward-facing standby state. The soiling on the polymethylmethacrylate and glass set on the tracker systems with both standby states was evaluated for 20 months in Miyazaki, Japan. By adopting the tracker system with the downward-facing standby state, a direct transmittance that was more-than-5% higher than before was consistently obtained at 500 nm in both cases with polymethylmethacrylate and glass.
DOI： 10.1155/2019/1296065
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Araki K., Ota Y., Lee K., Nishioka K., Yamaguchi M.
AIP Conference Proceedings 2149 2019.8
Language：English Publishing type：Research paper (international conference proceedings) Publisher：AIP Conference Proceedings
© 2019 American Institute of Physics Inc.. All rights reserved. It is well known that CPV is sensitive to the spectrum change, and its high-performance is often discouraged by the spectrum mismatching loss by the seasonal change of the atmospheric parameters. We found multiple methods could improve the robustness to the spectrum sensitivity, including enhancing luminescence coupling and fine-tuning to the bottom-bandgap matched to local atmospheric conditions (water absorption).
DOI： 10.1063/1.5124194