Browsing by Author "Chuang, Ming-Kai"

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Accumulated plasmonic effects of gold nanoparticle-decorated PEGylated graphene oxides in organic light-emitting diodes
(2020-09-01)
Chuang, Ming-Kai
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Lin, Chun-Hao
;
Chen, Fang-Chung
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交大名義發表
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光電工程學系
Amphiphilic Au nanoparticle-decorated PEGylated graphene oxides (Au@PEG-GO) are used to construct multiple plasmonic nanostructures for enhancing the performance of organic light-emitting diodes (OLEDs). Because of the long side-chains of the Au@PEG-GO nanocomposites, the nanoparticles can be well dispersed both in organic and aqueous solvents, allowing them to be incorporated readily into the buffer layers, such as poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT:PSS) and the organic photoactive layers within OLEDs during the soultion processes. Herein, the Au@PEG-GO nanocomposites are blended into either the PEDOT:PSS or the emissive layer of OLEDs to trigger surface plasmonic effects, thereby improving the device efficiencies. The current efficiencies are improved by ca. 20% for both cases. More importantly, the simultaneous addition of the Au@PEG-GO nanocomposites into both layers leads to even pronounced plasmonic effects. Under the optimized condition, the current efficiency is enhanced by up to 38%, suggesting the plasmonic fields from both layers attributed to the device enhancement. We anticipate that the accumulated plasmonic effects originating from the multiple plasmonic nanostructures will open up new avenues for improving the performance of various solution-processed optoelectronic devices involving organic dyes.
Efficient and stable polymer solar cells prepared using plasmonic graphene oxides as anode buffers
(2015-08-01)
Chen, Chung-Lei
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Chuang, Ming-Kai
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Chen, Chyong-Hua
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Chu, Chih-Wei
;
Keshtov, Muchamed L.
Gold nanoparticle-decorated graphene oxides (AuNP-GOs) have been incorporated into inverted organic photovoltaic devices (OPVs) as anode interlayers. The OPVs fabricated with AuNP-GOs exhibited significant improvement in both the short-circuit current and fill factor compared to a reference device fabricated with neat GOs. We attribute the improvement in the efficiency of the device to the plasmonic effects of the AuNP-GO nanocomposites, which induced local enhancement of the electromagnetic field. More importantly, the inverted OPVs also exhibited better reliability after the use of AuNP-GO nanocomposites.
Flexible polymer solar cells prepared using hard stamps for the direct transfer printing of polymer blends with self-organized interfaces
(2011)
Chen, Fang-Chung
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Chuang, Ming-Kai
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Chien, Shang-Chieh
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Fang, Jheng-Hao
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Chu, Chih-Wei
A transfer printing technique allows the development of flexible photovoltaic devices. Blending poly (ethylene glycol) (PEG) in the photoactive layer causes the PEG molecules to migrate spontaneously to and weaken the bonding at the interface between the polymer film and the Si wafer, thereby facilitating the transfer process from a hard stamp to the receiving flexible substrate. The device fabricated using this transfer printing process had characteristics similar to those of the corresponding device prepared using a spin-coating process. Using hard stamps should help to realize the low-cost, high-throughput roll-to-roll fabrication of flexible solar cells.
Gold nanoparticle-decorated graphene oxides for plasmonic-enhanced polymer photovoltaic devices
(2014)
Chuang, Ming-Kai
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Lin, Shih-Wei
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Chen, Fang-Chung
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Chu, Chih-Wei
;
Hsu, Chain-Shu
In this work, gold nanoparticle/graphene oxide (AuNP/GO) nanocomposites are synthesized and used as anodic buffer layers in organic photovoltaic devices (OPVs). The application of thiol-terminated polyethylene glycol as a capping agent prevents the aggregation of AuNPs on the GO surface and further improves the solubility and stability of these nanomaterials in solutions. When AuNP/GO nanomaterials served as the buffer layers, they introduced localized surface plasmon resonance (LSPR) in the OPVs, leading to noticeable enhancements in the photocurrent and the efficiencies of the OPVs. We attribute the primary origin of the improvement in device performance to local field enhancement induced by the LSPR. We anticipate that this study might open up new avenues for constructing plasmon-enhancing layers on the nanoscale to improve the performance of solar cells.
Gold Nanoparticle-Graphene Oxide Nanocomposites That Enhance the Device Performance of Polymer Solar Cells
(2014-01-01)
Chuang, Ming-Kai
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Chen, Fang-Chung
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Hsu, Chain-Shu
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應用化學系
;
光電工程學系
Metal nanoparticle-decorated graphene oxides are promising materials for use in various optoelectronic applications because of their unique plasmonic properties. In this paper, a simple, environmentally friendly method for the synthesis of gold nanoparticle-decorated graphene oxide that can be used to improve the efficiency of organic photovoltaic devices (OPVs) is reported. Here, the amino acid glycine is employed as an environmentally friendly reducing reagent for the reduction of gold ions in the graphene oxide solutions. Transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, UV-Vis spectroscopy, and Raman spectroscopy are used to characterize the material properties of the resulting nanomaterials. Furthermore, these nanocomposites are employed as the anode buffer layer in OPVs to trigger surface plasmonic resonance, which improved the efficiency of the OPVs. The results indicate that such nanomaterials appear to have great potential for application in OPVs.
Metal Nanoparticle-Decorated Two-Dimensional Molybdenum Sulfide for Plasmonic-Enhanced Polymer Photovoltaic Devices
(2015-08-01)
Chuang, Ming-Kai
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Yang, Shun-Shing
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Chen, Fang-Chung
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光電工程學系
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Department of Photonics
Atomically thin two-dimensional (2D) transition metal dichalcogenides have also attracted immense interest because they exhibit appealing electronic, optical and mechanical properties. In this work, we prepared gold nanoparticle-decorated molybdenum sulfide (AuNP@MoS2) through a simple spontaneous redox reaction. Transmission electron microscopy, UV-Vis spectroscopy, and Raman spectroscopy were used to characterize the properties of the AuNP@MoS2 nanomaterials. Then we employed such nanocomposites as the cathode buffer layers of organic photovoltaic devices (OPVs) to trigger surface plasmonic resonance, leading to noticeable enhancements in overall device efficiencies. We attribute the primary origin of the improvement in device performance to local field enhancement induced by the effects of localized surface plasmonic resonance. Our results suggest that the metal nanoparticle-decorated two-dimensional materials appear to have great potential for use in high-performance OPVs.
Near-infrared laser-driven polymer photovoltaic devices and their biomedical applications
(2011-09-01)
Wu, Jyh-Lih
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Chen, Fang-Chung
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Chuang, Ming-Kai
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Tan, Kim-Shih
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光電工程學系
We demonstrate near-infrared laser-driven (NIRLD) organic photovoltaic devices (OPVs), which can directly convert 980 nm light into electrical power. We attribute the NIR photovoltaic response to the long-wavelength absorption of charge transfer (CT) states. Direct excitation through CT states might open up new avenues for harvesting the long-wavelength spectrum of solar irradiation. Further, because of the high transparency of biological tissue toward 980 nm light, these NIRLD OPVs might be a promising wireless electrical source for biological nanodevices.
Photoexfoliation of two-dimensional materials through continuous UV irradiation
(2017-03-24)
Lin, Wai-Chen
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Chuang, Ming-Kai
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Keshtov, Muchamed L.
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Sharma, Ganesh D.
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Chen, Fang-Chung
This paper describes the preparation of fluorinated graphene nanosheets (FGNs) through photoexfoliation of fluorinated graphite (FG) in the liquid phase. We discovered that UV irradiation of FG dispersions in N-methyl-2-pyrolidone facilitated exfoliation to give FGNs. Transmission electron microscopy and atomic force microscopy revealed that the average thickness of the FGNs was approximately 3 nm; they were considerably thinner than the nanosheets prepared using a conventional sonication approach. Furthermore, when the FGNs were deposited uniformly onto substrates (through spin coating), they formed effective cathode interlayers for polymer solar cells (PSCs), the efficiency of which was 60% greater than that of PSCs containing FGNs prepared through ultrasonication.
Plasmonic Effects of Amphiphilic Gold Nanoparticles in Polymer Optoelectronic Devices
(2016)
Chuang, Ming-Kai
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Lin, Chun-Hao
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Chen, Fang-Chung
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光電工程學系
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Department of Photonics
Amphiphilic gold nanoparticles have been synthesized and employed for improving the performance of polymer optoelectronics devices. Such nanocomposites could be readily incoporated into the buffer and/or photoactive layers, resulting in obvious enhancements in device efficiencies.
Plasmonic Effects on Bulk Heterojunction Polymer Solar Cells: A Transient Photovoltage and Differential Charging Study
(2017-08-01)
Kok, Soon Yie
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Hsieh, Zong-Chun
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Chou, Chun-Hsien
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Yang, Shun-Shing
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Chuang, Ming-Kai
Transient photovoltage and differential charging experiments have been carried out to investigate the plasmonic effects in organic photovoltaic devices (OPVs). We observed that the carrier lifetimes became longer after the Au nanoparticles were blended into the OPVs. Additionally, the charge carrier densities also became higher in the bulk of the device. The carrier lifetime, however, usually follows an inverse power relationship with the increasing charge density in OPVs fabricated base on the concept of bulk heterojunctions. Therefore, we conclude that one of the limitations for the plasmonic approaches could be the strong bimolecular recombination.
Solution-Processed Nanocomposites Containing Molybdenum Oxide and Gold Nanoparticles as Anode Buffer Layers in Plasmonic-Enhanced Organic Photovoltaic Devices
(2013-12-11)
Tan, Kim-Shih
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Chuang, Ming-Kai
;
Chen, Fang-Chung
;
Hsu, Chain-Shu
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應用化學系
Solution-processed nanocomposites containing molybdenum oxide (MoO3) and gold nanoparticles (Au NPs) have been used as anode buffer layers in organic photovoltaic devices (OPVs). The resulting devices exhibit a remarkable enhancement in power conversion efficiency after Au NPs were incorporated into the device. Such enhancements can be attributed to the localized surface plasmon resonance induced by the metallic nanostructures. We have also found that the rate of exciton generation and the probability of exciton dissociation were increased. Furthermore, the devices made of the MoO3 buffer layer containing Au NPs exhibited superior stability. This work opens up the possibility of fabricating OPVs with both high efficiency and a prolonged lifetime.
Surface Plasmonic Effects of Nanostructures on the Performance of Polymer Solar Cells
(2015)
Chuang, Ming-Kai
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Wu, Jyh-Lih
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Chien, Shang-Chieh
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Chen, Fang-Chung
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光電工程學系
In this chapter, we review recent progress related to the incorporation of plasmonic nanostructures in organic photovoltaic devices (OPVs) as a means of enhancing power conversion efficiencies. We begin by describing the fundamental properties of surface plasmons (SPs). We then outline the two primary schemes that are commonly employed for excitation of the SPs: the use of noble metal particles to trigger the SPs and the creation of propagating surface plasmon polaritons (SPP) through approaches that can overcome the problem of momentum mismatch (e. g., periodic corrugation at the metal-dielectric interface). Next, we discuss some recent remarkable approaches toward increasing the light absorption efficiency of OPVs, highlighting three categories of plasmonic structures that enhance the performance of OPVs. Finally, we provide a brief outlook regarding the future use of SPs in high-efficiency OPVs.
Synergistic Plasmonic Effects of Metal Nanoparticle-Decorated PEGylated Graphene Oxides in Polymer Solar Cells
(2015-04-08)
Chuang, Ming-Kai
;
Chen, Fang-Chung
;
光電工程學系
;
Department of Photonics
Metal nanostructures that trigger plasmonic near-field effects are often incorporated in organic photovoltaic devices (OPVs) to improve their light-harvesting ability. These nanostructures usually can be positioned in two different locations in a device: (i) within the photon absorption layers and (ii) at the interfaces between the active layer and the metal electrodes. In this study, we developed amphiphilic gold nanoparticles (Au NPs) for use in dual plasmonic nanostructures within OPVs. We employed graphene oxide as the template to anchor the Au NPs, thereby avoiding their aggregation. Furthermore, we added poly(ethylene glycol) (PEG) bis(amine) to the synthesis medium to improve the solubility of the nanocomposites, such that they could be dispersed well in water and in several organic solvents. Accordingly, we could incorporate the PEGylated Au NP/graphene oxides readily into both the buffer layer and photoactive layer of OPVs, which, as a result, exhibited obvious enhancements in their photocurrents and overall device efficiencies. Moreover, we observed different spectral enhancement regions when we positioned the nanocomposites at different locations, reflecting the different dielectric environments surrounding the NPs; this unexpected behavior should assist in enhancing the broadband absorption of solar irradiation.