Browsing by Author "Huang, Bo-Yu"

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Characteristics of large-scale nanohole arrays for thin-silicon photovoltaics
(2014-04-01)
Chen, Ting-Gang
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Yu, Peichen
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Chen, Shih-Wei
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Chang, Feng-Yu
;
Huang, Bo-Yu
Nanostructured crystalline silicon is promising for thin-silicon photovoltaic devices because of reduced material usage and wafer quality constraint. This paper presents the optical and photovoltaic characteristics of silicon nanohole (SiNH) arrays fabricated using polystyrene nanosphere lithography and reactive-ion etching (RIE) techniques for large-area processes. A post-RIE damage removal etching is subsequently introduced to mitigate the surface recombination issues and also suppress the surface reflection due to modifications in the nanohole sidewall profile, resulting in a 19% increase in the power conversion efficiency. We show that the damage removal etching treatment can effectively recover the carrier lifetime and dark current-voltage characteristics of SiNH solar cells to resemble the planar counterpart without RIE damages. Furthermore, the reflectance spectra exhibit broadband and omnidirectional anti-reflective properties, where an AM1.5 G spectrum-weighted reflectance achieves 4.7% for SiNH arrays. Finally, a three-dimensional optical modeling has also been established to investigate the dimension and wafer thickness dependence of light absorption. We conclude that the SiNH arrays reveal great potential for efficient light harvesting in thin-silicon photovoltaics with a 95% material reduction compared to a typical cell thickness of 200 mu m. Copyright (c) 2012 John Wiley & Sons, Ltd.
Fabrication and Device Modeling of Micro-textured Conductive Polymer/Silicon Heterojunction Solar Cells
(2012)
Chen, Ting-Gang
;
Huang, Bo-Yu
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Huang, Yang-Yue
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Chen, En-Chen
;
Yu, Peichen
In this paper, hybrid heterojunction solar cells are demonstrated based on a highly conductive polymer PEDOT:PSS directly spun-cast on an n-type crystalline silicon with microscale surface textures. The fabrication conditions suggest that the organic coverage on the micro-textured surface is excellent and key to achieve high efficiency. The simple solution-based fabrication processes achieved a cell power conversion efficiency of 10.2%. Device modeling had been performed to investigate the interface defect density dependence of cell performances. A power conversion efficiency of above 20% is projected for the hybrid heterojunction cells, showing promises for low-cost photovoltaics.
FABRICATION AND MODELING OF LARGE-SCALE SILICON NANOWIRE SOLAR CELLS FOR THIN-FILM PHOTOVOLTAICS
(2012)
Cheng, Yu-Chih
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Chen, Ting-Gang
;
Chang, Feng-Yu
;
Huang, Bo-Yu
;
Pan, Huai-Te
Nanostructured crystalline silicon is promising for thin photovoltaic devices due to reduced material usage and wafer quality constraint. In this study, a simple and cost-effective method is presented for producing large-area silicon nanowire (SiNW) arrays with various lengths by employing the polystyrene nanosphere lithography and the metal-assisted chemical etching (MACE). The nanowire structure exhibits broadband and omnidirectional antireflection properties, where the lowest AM1.5G-spectrum-weighted reflectance of SiNW arrays is 4.38%, compared to 8.84% of the conventional single layer antireflection coating (SLARC). Next, we made SiNW array structures into solar cells and its power efficiency achieved 10.8%. Afterward, the SiNW array solar cells were analyzed by external and internal quantum efficiency measurement which shows the device performance primarily limited by direct and indirect interfacial recombination of charge carriers. We further develop a modeling technique based on three-dimensional (3) optical and two-dimensional (20) electrical simulations which are tailored for the nanostructured silicon photovoltaic devices. The optical simulation employs a rigorous couple wave analysis (RCWA) technique to calculate the distribution of electromagnetic field in order to obtain the generation rate within the nanostructure. Next, an electrical calculation is based on a 20 self-consistent drift-diffusion and Poisson solver using a finite element method (FEM). We investigate the influence to the device performance of carrier diffusion length with three different structures. The simulation results show that a short diffusion length does not seriously deteriorate the short-circuit current density and power conversion efficiency of a core-shell PN junction solar cell compared to the conventional planar structure. Our work suggests that SiNW solar cells can achieve efficient light harvesting and photoelectric conversion with less and lower-grade materials than the conventional technology, which is promising for thin silicon photovoltaics.
Flexible Silver Nanowire Meshes for High-Efficiency Microtextured Organic-Silicon Hybrid Photovoltaics
(2012-12-01)
Chen, Ting-Gang
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Huang, Bo-Yu
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Liu, Hsiao-Wei
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Huang, Yang-Yue
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Pan, Huai-Te
Hybrid organic-silicon heterojunction solar cells promise a significant reduction on fabrication costs by avoiding energy-intensive processes. However, their scalability remains challenging without a low-cost transparent electrode. In this work, we present solution-processed silver-nanowire meshes that uniformly cover the microtextured surface of hybrid heterojunction solar cells to enable efficient carrier collection for large device area. We systematically compare the characteristics and device performance with long and short nanowires with an average length/diameter of 30 mu m/115 nm and 15 mu m/45 nm, respectively, to those with silver metal grids. A remarkable power conversion efficiency of 10.1% is achieved with a device area of 1 x 1 cm(2) under 100 mW/cm(2) of AM1.5G illumination for the hybrid solar cells employing long wires, which represents an enhancement factor of up to 36.5% compared to the metal grid counterpart. The high-quality nanowire network displays an excellent spatial uniformity of photocurrent generation via distributed nanowire meshes and low dependence on efficient charge transport under a high light-injection condition with increased device area. The capability of silver nanowires as flexible transparent electrodes presents a great opportunity to accelerate the mass deployment of high-efficiency hybrid silicon photovoltaics via simple and rapid soluble processes.
High-Throughput Screening of Sulfated Proteins by Using a Genome-Wide Proteome Microarray and Protein Tyrosine Sulfation System
(2017-03-21)
Huang, Bo-Yu
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Chen, Po-Chung
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Chen, Bo-Han
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Wang, Chen-Chu
;
Liu, Hsuan-Fu
Protein tyrosine sulfation (PTS) is a widespread posttranslational modification that induces intercellular and extracellular responses by regulating protein protein interactions and enzymatic activity. Although PTS affects numerous physiological and pathological processes, only a small fraction of the total predicted sulfated proteins has been identified to date. Here, we localized the potential sulfation sites of Escherichia coli proteins on a proteome microarray by using a 3'-phosphoadenosine 5'-phosphosulfate (PAPS) synthase-coupled tyrosylprotein sulfotransferase (TPST) catalysis system that involves in situ PAPS generation and TPST catalysis. Among the 4256 E. coil K12 proteins, 875 sulfated proteins were identified using antisulfotyrosine primary and Cy3-labeled antimouse secondary antibodies. Our findings add considerably to the list of potential proteins subjected to tyrosine sulfation. Similar procedures can be applied to identify sulfated proteins in yeast and human proteome microarrays, and we expect such approaches to contribute substantially to the understanding of important human diseases.
Micro-textured conductive polymer/silicon heterojunction photovoltaic devices with high efficiency
(1970-01-01)
Chen, Ting-Gang
;
Huang, Bo-Yu
;
Chen, En-Chen
;
Yu, Peichen
;
Meng, Hsin-Fei
"In this work, hybrid heterojunction solar cells are demonstrated based on a conjugate polymer poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) directly spun-cast on micro-textured n-type crystalline silicon wafers. The fabrication conditions suggest that the organic coverage on the micro-textured surface is excellent and key to achieve high efficiency, leading to an average power conversion efficiency of 9.84%. A one-dimensional drift-diffusion model is then developed based on fitting the device characteristics with experimentally determined PEDOT: PSS parameters and projects an ultimate efficiency above 20% for organic/inorganic hybrid photovoltaics. The simulation results reveal the impacts of defect densities, back surface recombination, doping concentration, and band alignment. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4734240]"
Solution-processed Silicon Hybrid Heterojunction Photovoltaics with Silver Nanowires
(2012-01-01)
Huang, Bo-Yu
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Liu, Hsiao-Wei
;
Chen, Ting-Gang
;
Chen, En-Chen
;
Chen, Bo-han
An Organic/inorganic hybrid solar cells are cheap alternatives to conventional silicon-based solar cells. The devices take the advantages of high optical absorption and carrier mobility of inorganic semiconductors, while maintaining the easy processing attributes of polymers or other soft materials. However, the conduction of holes has been a major technical barrier for the advance of such novel devices. In this study, we propose the use of silver nanowires (AgNWs) to improve the series resistance of the hybrid solar cells and further to realize solution-processed silicon-based photovoltaics. The hybrid silicon heterojunction solar cells are demonstrated based on the composite of conductive polymer PEDOT:PSS directly spun-cast on a micro-textured n-type crystalline silicon wafer, followed by the Meyer rod coating of AgNWs as the frontal metal contacts. The cross linked AgNWs offer high transparency and low sheet resistance, which can be easily fabricated using low-cost and non-toxic materials. Moreover, the industrial-standard microscale surface textures improve the antireflection and carrier collection without increasing much surface recombination. As a result, the device current density-voltage characteristics reveals a high power conversion efficiency of 6.8% under a calibrated illumination intensity of 1000 W/m(2) of the AM1.5G solar spectrum, shedding light into the attainment of rapid solution processed silicon hybrid heterojunction solar cells.
Surface composition and interactions of mobile charges with immobilized molecules on polycrystalline silicon nanowires
(2015-05-01)
Lin, Chih-Heng
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Feng, Mei-Huei
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Hwang, Chi-Hung
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Wu, Jennifer Yun-Shin
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Su, Ping-Chia
The polycrystalline silicon nanowire field-effect transistor (poly-SiNW FET) is one of the most sensitive sensors used in real-time and label-free biosensing applications. Its low power requirement, mass production potential, and integrability with electronic components make it a highly attractive device in the rapidly growing diagnostic research field. From the viewpoint of device physics, the charges in the vicinity of a nanowire (NW) surface modulate the electrical characteristics of the NW device. The charges can originate from surface molecules or an ionic solution, and their role in NW biosensing systems remains to be clarified. Determining their role is crucial for understanding the physical interactions of charges in a biosensing event and for the realization of NW-based biosensors. Therefore, using poly-SiNW FET, we investigated the interactions of the immobilized molecules on the NW surface with the mobile charges in solutions. We also investigated the interactions between the mobile charged polymers and the immobilized molecules on the NW surface, and we observed the effect of charge neutrality, originating from Coulomb charge-charge interactions, on the NW conductance. Finally, the isoelectric points between native and sulfated PSGL-1 peptides on the NW surface were identified. This study provides a physical understanding of the charge-charge interaction of mobile charges with immobilized charged molecules on a nanoscale surface and presents new opportunities for using charge-based detection in biological and chemical sensing applications. (C) 2015 Elsevier B.V. All rights reserved.