Browsing by Author "Peng, Cheng-Hsiung"

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Annealing Effect on Photovoltaic Performance of Hybrid P3HT/In-Situ Grown CdS Nanocrystal Solar Cells
(2011)
Liao, Hung-Chou
;
Chantarat, Naratip
;
Chen, San-Yuan
;
Peng, Cheng-Hsiung
;
材料科學與工程學系
The CdS nanocrystals with different aspect ratios (ARs) can be synthesized directly in the presence of conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT). The UV-vis spectra of the composite films show a blue shift of the pi-pi* transition band with an increasing aspect ratio (AR) of the CdS nanocrystals, which was attributed to the destruction of the ordered structure of polymer chains as supported by PL measurements. Atomic force microscope measurements on P3HT/CdS film also demonstrate the aggregation of CdS nanocrystal in the P3HT matrix is more apparent for the CdS nanocrystals of AR 4 than that of AR 16, indicating a stronger interaction between P3HT and CdS for a larger AR (16), which is favorable for the network structure and formation of percolation paths to increase the transport properties of the P3HT/CdS solar cells. Therefore, a higher power conversion efficiencies (PCE) up to 2.95% can be obtained for the in-situ-grown P3HT/CdS with AR 16 upon annealing treatment at 160 degrees C for 60 min. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3585668] All rights reserved.
Fabrication and Characterization of Mg-Doped ZnO Nanorod Arrays
(2010-07-01)
Liao, Hung-Chou
;
Chen, San-Yuan
;
Peng, Cheng-Hsiung
;
Lin, Chin-Ching
;
Cheng, Syh-Yuh
Photoelectronic characteristics are investigated in well-aligned MgO-coated ZnO nanorods (MgO/ZnO nanocables) grown on Si substrates buffered with ZnO film at a low temperature by solution techniques. Transmission electron microscopy shows that a rough surface was observed for the MgO-coated ZnO nanorods due to deposition of MgO nanoparticles on the surface of the ZnO nanorods. However, after annealed at high temperatures, the surface of the MgO-coated ZnO nanorods was flattened to form Mg-doped ZnO nanorods. Photoluminescence spectra of Mg-doped ZnO nanorods displayed a blue shift of the near-band-edge emission with increasing annealing temperature indicative of an increase in the band gap of the MgZnO alloy due to diffusion of the Mg atoms into the ZnO nanorods. In contrast, no blue shift was detected for the samples annealed in H(2)/N(2) (5%/95%) reduction atmosphere but a blue emission was detected at 800 degrees C, indicating that MgO diffusion process may produce a new luminescent center to emit the blue emission in H(2)/N(2) reduction atmosphere.
Improved Current Density with Al(2)O(3) Coated ZnO Nanorod in Hybrid Solar Cell
(2010-07-01)
Lin, Shih-Chin
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Chen, San-Yuan
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Peng, Cheng-Hsiung
;
材料科學與工程學系
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Department of Materials Science and Engineering
Heterojunction photovoltaic devices consisting of hybrid p-type organic Cu-phthalocyanine and inorganic n-type Al(2)O(3) nanoparticle-coated aligned ZnO nanorods were fabricated. With microwave treatment, an interaction occurred between the Al(2)O(3) and ZnO, as evidenced from TEM image. This interaction shifts the absorption peak of the aligned nanorods from the UV region to visible light and subsequently causes more charge generation. For 5 mol% Al(2)O(3) nanoparticle-coated aligned ZnO nanorods treated with microwaves of 600 W for 300 sec, the maximum incident photon to electron conversion and energy conversion efficiencies under simulated sunlight of AM1.5G (10 mW/cm(2)) are 0.036 mA and 1.32%, respectively.
Improved Current Density with Al2O3 Coated ZnO Nanorod in Hybrid Solar Cell
(2010-07-01)
Lin, Shih-Chin
;
Chen, San-Yuan
;
Peng, Cheng-Hsiung
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Heterojunction photovoltaic devices consisting of hybrid p-type organic Cu-phthalocyanine and inorganic n-type Al2O3 nanoparticle-coated aligned ZnO nanorods were fabricated. With microwave treatment, an interaction occurred between the Al2O3 and ZnO, as evidenced from TEM image. This interaction shifts the absorption peak of the aligned nanorods from the UV region to visible light and subsequently causes more charge generation. For 5 mol% Al2O3 nanoparticle-coated aligned ZnO nanorods treated with microwaves of 600 W for 300 sec, the maximum incident photon to electron conversion and energy conversion efficiencies under simulated sunlight of AM1.5G (10 mW/cm(2)) are 0.036 mA and 1.32%, respectively.
Multi-Metals CaMgAl Metal-Organic Framework as CaO-based Sorbent to Achieve Highly CO2 Capture Capacity and Cyclic Performance
(2020-05-01)
Wu, Szu-Chen
;
Chang, Po-Hsueh
;
Lin, Chieh-Yen
;
Peng, Cheng-Hsiung
;
材料科學與工程學系
In this study, Ca-based multi-metals metal-organic framework (CaMgAl-MOF) has been designed as precursor material for carbon dioxide (CO2) capture to enhance the CO2 capture capacity and stability during multiple carbonation-calcination cycles. The CaMgAl-MOFs were constructed from self-assembly of metal ions and organic ligands through hydrothermal process to make metal ions uniformly distributed through the whole structure. Upon heat treatment at 600 degrees C, the Ca-based multi-metals CaMgAl-MOF would gradually transform to CaO and MgO nanoparticles along with the amorphous aluminum oxide distributed in the CaO matrix. XRD, Fourier transform infrared (FTIR), and SEM were used to identify the structure and characterize the morphology. The CO2 capture capacity and multiple carbonation-calcination cyclic tests of calcined Ca-based metal-organic framework (MOF) (attached with O and indicated as Ca-MOF-O) were performed by thermal gravimetric analysis (TGA). The single metal component calcined Ca-MOF sorbent have the highest CO2 capture capacity up to 72 wt.%, but a lower stability of 61% due to severe particle aggregation. In contrast, a higher Ca-rich MOF oxide sorbent with tailoring the Mg/Al ratios, Ca0.97Mg0.025Al0.005-MOF-O, showed the best performance, not only having the high stability of similar to 97%, but also maintaining the highest capacity of 71 wt.%. The concept of using Ca-based MOF materials combined with mixed-metal ions for CO2 capture showed a potential route for achieving efficient multiple carbonation-calcination CO2 cycles.
Structure and photoluminescence properties of strong blue-emitting alumina film developed from a liquid sol at low temperature
(2010-02-18)
Peng, Cheng-Hsiung
;
Hwang, Chyi-Ching
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Hsiao, Chi-Sheng
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材料科學與工程學系
;
Department of Materials Science and Engineering
Strong blue photoluminescence emission at 450 nm from alumina films prepared from an alumina precursor was observed. Photo luminescence measurements indicate that the peak intensity of the blue emission changes with the pH value of the peptizing solution, the annealing temperature and the atmosphere. The blue emission appears at a low temperature of 50 degrees C and reaches a maximum strength at 400 degrees C in an oxygen atmosphere and 600 degrees C in a nitrogen atmosphere. HRTEM images show that the alumina films are composed of nanoparticles with a diameter of <= 10 nm. it is believed that the observed strong photoluminescence is associated with inherent defect centers in the material, where these are related to the structure transition and transformation from the boehmite phase to the gamma-alumina phase and bond cleavage. (C) 2009 Elsevier B.V. All rights reserved.