化學系
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國立臺灣師範大學化學系座落於公館校區理學院大樓。本系成立於民國五十一年，最初僅設大學部。之後於民國六十三年、七十八年陸續成立化學研究所碩士班和博士班。本系教育目標旨在培養化學專業人才與中等學校自然及化學專業師資，授課著重理論及應用性。本系所現有師資為專任教授25人，另外尚有與中央研究院合聘教授3位，在分析、有機、無機及物理化學四個學門的基礎上發展跨領域之教學研究合作計畫。此外，本系另有助教13位，職技員工1位，協助處理一般學生實驗及行政事務。學生方面，大學部現實際共322人，碩士班現實際就學研究生共174人，博士班現實際就學共55人。
本系一向秉持著教學與研究並重，近年來為配合許多研究計畫的需求，研究設備亦不斷的更新。本系所的研究計畫大部分來自國科會的經費補助。此外，本系提供研究生獎助學金，研究生可支領助教獎學金（TA）、研究獎學金（RA）和部分的個別教授所提供的博士班學生獎學金（fellowships）。成績優良的大學部學生也可以申請獎學金。
本校圖書館藏書豐富，除了本部圖書館外，分部理學院圖書館西文藏書現有13萬餘冊，西文期刊合訂本有911餘種期刊，將近約3萬冊。此外，西文現期期刊約450種，涵蓋化學、生化、生物科技、材料及其他科學類等領域。目前本系各研究室連接校園網路，將館藏查詢、圖書流通、期刊目錄轉載等功能，納入圖書館資訊系統中，並提供多種光碟資料庫之檢索及線上資料庫如Science Citation Index，Chemical Citation Index，Chemical Abstracts，Beilstein，MDL資料庫與STICNET全國科技資訊網路之查詢。
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Item Low-Frequency Contact Noise of GaN Nanowire Device Detected by Cross-Spectrum Technique.(Japan Society of Applied Physics, 2011-06-01) L.-C. Li; K.-H. Huang; J.-A. Wei; Y.-W. Suen; T.-W. Liu; Chia-Chun Chen; L.-C. Chen; K.-H. ChenWe report the properties of low-frequency contact noise of multielectrode GaN nanowire (NW) devices. A two-port cross-spectrum technique is used to discriminate the noise of the ohmic contact from that of the NW section. The diameter of the GaN NW is around 100 nm. The Ti/Al electrodes of the NWs are defined by e-beam lithography. The typical resistance of a NW section with a length of 800 nm is about 5.5 kΩ and the two-wire resistance is below 100 kΩ. The results show that the low-frequency excess noise of the GaN NW is much smaller than that of the current-flowing contact, indicating that the contact noise dominates the noise behavior in our GaN NW devices. A careful study of the noise amplitude (A) of the 1/f noise of different types of NW and carbon nanotube devices, both in our work and in the literature, yields an empirical formula for estimating A from the two-wire resistance of the device.Item Vitalizing fuel cells with vitamins: pyrolyzed vitamin B12 as a non-precious catalyst for enhanced oxygen reduction reaction of polymer electrolyte fuel cells(Royal Society of Chemistry, 2012-01-01) S.-T. Chang; C.-H. Wang; H.-Y. Du; H.-C.Hsu; C.-M. Kang; Chia-Chun Chen; J.C.-S. Wu; S.-C. Yen; W.-F. Huang; L.-C. Chen; M.-C. Lin; K.-H. ChenThe limited natural abundance and high cost of Pt has been a major barrier in its applications for hydrogen or methanol fuel cells. In this work, based on the pyrolyzed corrin structure of vitamin B12 (py-B12/C), it is reported to produce superior catalytic activity in the oxygen reduction reaction (ORR) with an electron transfer number of 3.90, which is very close to the ideal case of 4. The H2–O2fuel cell using py-B12/C provides a maximum power density of 370 mW cm−2 and a current density of 0.720 A cm−2 at 0.5 V at 70 °C. Calculations based on density functional theory suggests that the corrin complex with a low-symmetric structure offers a much preferable path for the ORR, which is not applicable to the porphyrin with a high-symmetric structure. The long-term stability and high ORR activity of py-B12/C make it a viable candidate as a Pt-substitute in the ORR.Item Flexible supercapacitor based on polyaniline nanowires/carbon cloth with both high gravimetric and area-normalized capacitance(Elsevier, 2010-07-01) Y.-Y. Horng; Y.-C. Lu; Y.-K. Hsu; Chia-Chun Chen; L.-C. Chen; K.-H. ChenFlexible supercapacitor is successfully fabricated using polyaniline nanowires/carbon cloth (PANI-NWs/CC) nanocomposite. High gravimetric capacitance of 1079 F g−1 at a specific energy of 100.9 Wh kg−1 and a specific power of 12.1 kW kg−1 is obtained. Moreover, this approach also offers an exceptionally high area-normalized capacitance of 1.8 F cm−2. The diffusion length of protons within the PANI-NWs is estimated to be about 60 nm by electrochemical impedance analysis, which indicates that the electrochemical performance of the electrode is not limited by the thickness of PANI-NWs. The electrochemical performance of PANI-NWS/CC remains without any deterioration, even when the cell is bent under high curvature. These results clearly present a cost-effective and simple method of fabrication of the nanostructured polymers with enormous potential in flexible energy storage device applications.Item Controlled growth of aligned alpha-helical-polypeptide brushes for tunable electrical conductivity(American Institute of Physics, 2011-03-28) J.-C. Wu; Chia-Chun Chen; K.-H. Chen; Y.-C. ChangPolypeptide based molecular diode with high rectification ratio (∼122 at ±0.422 V) is formed by controlling molecular order and orientation. A film of tethered poly(γ-benzyl-L-glutamate) (PBLG) with high degree of molecular orientation was formed by solvent pair (good/bad) treatment. I-V characterization of the well aligned polypeptides showed that the rectification ratio of PBLG was sufficiently large for potential diode and transistor applications.Item Low methanol-permeable polyaniline/Nafion composite membrane for direct methanol fuel cells(Elsevier, 2009-05-15) C.-H. Wang; Chia-Chun Chen; H.-C. Hsu; H.-Y. Du; C.-R. Chen; J.-Y. Hwang; L.-C. Chen; H.-C. Shih; J. Stejskal; K.-H. ChenProtonated polyaniline (PANI) is directly polymerized on Nafion 117 (N117), forming a composite membrane, to act as a methanol-blocking layer to reduce the methanol crossover in the direct methanol fuel cell (DMFC), which is beneficial for the DMFC operating at high methanol concentration. The PANI layer grown on the N117 with a thickness of 100 nm has an electrical conductivity of 13.2 S cm−1. The methanol permeability of the PANI/N117 membrane is reduced to 59% of that of the N117 alone, suggesting that the PANI/N117 can effectively reduce the methanol crossover in the DMFC. Comparison of membrane-electrode-assemblies (MEA) using the conventional N117 and the newly developed PANI/N117 composite shows that the PANI/N117-based MEA outputs higher power at high methanol concentration, while the output power of the N117-based MEA is reduced at high methanol concentration due to the methanol crossover. The maximum power density of the PANI/N117-based MEA at 60 °C is 70 mW cm−2 at 6 M methanol solution, which is double the N117-based MEA at the same methanol concentration. The resistance of PANI/N117 composite membrane is reduced at elevated methanol concentration, due to the hydrogen bonding between methanol and PANI pushes the polymer chains apart. It is concluded that the PANI/N117-based MEA performs well at elevated methanol concentration, which is suitable for the long-term operation of the DMFC.Item Silver-Nanoparticle-Conjugated Polypeptide Brushes for Surface-Enhanced Raman Scattering(American Chemical Society, 2009-08-06) D.-Y. Wang; T.-S Teng; Y.-C. Wu; Y.-C. Lee; K.-H. Chen; C.-H. Chen; Y.-C. Chang; Chia-Chun ChenA soft surface-enhanced Raman scattering (SERS) substrate was fabricated based on a three-dimensional (3D) structure of biocompatible end-tethered poly(l-lysine) (“t-PLL”) with a brushlike configuration conjugated with silver nanoparticles (Ag NPs) (Ag NP-t-PLL film). The conjugation procedures were carefully adjusted to generate the films with different interval widths (W) between Ag NPs and diameters (D) of Ag NPs. The resulting film was then characterized by zeta potential, CD spectropolarimeter, and scanning electron microscopy. Furthermore, the studies of SERS enhancements using Ag NP-t-PLL film as a substrate were performed. The significant increases of SERS enhancements have been obtained as W/D was decreased from 0.9 to 0.2. Our results not only afford a facile fabrication of a 3D soft substrate for SERS with high sensitivity and biocompatibility but also offer great potentials for the development of new biosensors.Item On-chip Fabrication of Well-aligned and Contact-barrier-free GaN Nanobridge Devices with Ultrahigh Photocurrent Responsivity(Wiley-VCH Verlag, 2008-07-01) R.-S. Chen; S.-W. Wang; Z.-H. Lan; J. T.-H. Tsai; C.-T. Wu; L.-C. Chen; K.-H. Chen; Y.-S. Huang; Chia-Chun ChenBuilding nanobridges: Direct integration of an ensemble of GaN nanowires (n) onto a microchip produces a viable nanobridge (NB) device with good alignment and contact performance, the design of which demonstrates the potential of nanowires for sensor development. These GaN NBs have strong surface-enhanced photoconductivity with ultrahigh responsivityItem Direct-growth of Polyaniline Nanowires for Enzyme-immobilization and Glucose Detection(Elsevier, 2009-04-01) Y.-Y. Horng; Y.-K. Hsu; A. Ganguly; Chia-Chun Chen; L.-C. Chen; K.-H. ChenAmperometric enzyme biosensor based on the glucose oxidase (GOx) incorporated polyaniline nanowires (PANI-NWs) on carbon cloth (CC) electrode was demonstrated. The simple, direct-growth of PANI-NWs on CC, via electrochemical polymerization, provides free-standing, template-independent, hence almost (interfacial) defects-free nanostructures. The defect-free interfaces, along with the excellently sensitive organic nanostructured-surface, as evident from its significantly large effective surface area (24 times the geometric area) for redox-sensing, allows efficient entrapment/immobilization and sensing of biomolecules, via rapid electron-transfer at NWs-CC. The GOx-immobilized PANI-NWs/CC, even in initial unoptimized stage, exhibited an excellent sensitivity, ∼2.5 mA mM−1 cm−2, to glucose, over detection range 0–8 mM, adequate for clinical monitoring of human glucose levels. The report clearly reveals a cost-effective simple system possessing enormous potentiality for biosensors, bioenergy and bioelectronics applications.Item High-phase-purity zinc-blende InN on r-plane sapphire substrate with controlled nitridation pretreatment(American Institute of Physics (AIP), 2008-03-17) C.-L. Hsiao; T.-W. Liu; C.-T. Wu; H.-C. Hsu; G.-M. Hsu; L.-C. Chen; W.-Y. Shiao; C.-C. Yang; A. Gaellstroem; P.-O. Holtz; Chia-Chun Chen; K.-H. ChenHigh-phase-purity zinc-blende (zb) InN thin film has been grown by plasma-assisted molecular-beam epitaxy on r-plane sapphire substrate pretreated with nitridation. X-ray diffraction analysis shows that the phase of the InN films changes from wurtzite (w) InN to a mixture of w-InN and zb-InN, to zb-InN with increasing nitridation time. High-resolution transmission electron microscopy reveals an ultrathin crystallized interlayer produced by substrate nitridation, which plays an important role in controlling the InN phase. Photoluminescence emission of zb-InN measured at 20 K shows a peak at a very low energy, 0.636 eV, and an absorption edge at ∼0.62 eV is observed at 2 K, which is the lowest bandgap reported to date among the III-nitride semiconductors.Item Enhanced Emission of (In, Ga) Nitride Nanowires Embedded with Self-assembled Quantum Dots(Wiley-VCH Verlag, 2008-03-25) C.-W. Hsu; A. Ganguly; C.-H. Liang; Y.-T. Hung; C.-T. Wu; G.-M. Hsu; Y.-F. Chen; Chia-Chun Chen; K.-H. Chen; L.-C. ChenWe report the structure and emission properties of ternary (In,Ga)N nanowires (NWs) embedded with self-assembled quantum dots (SAQDs). InGaN NWs are fabricated by the reaction of In, Ga and NH3 via a vapor–liquid–solid (VLS) mechanism, using Au as the catalyst. By simply varying the growth temperature, In-rich or Ga-rich ternary NWs have been produced. X-ray diffraction, Raman studies and transmission electron microscopy reveal a phase-separated microstructure wherein the isovalent heteroatoms are self-aggregated, forming SAQDs embedded in NWs. The SAQDs are observed to dominate the emission behavior of both In-rich and Ga-rich NWs. Temperature-dependent photoluminescence (PL) measurements indicate relaxation of excited electrons from the matrix of the Ga-rich NWs to their embedded SAQDs. A multi-level band schema is proposed for the case of In-rich NWs, which showed an anomalous enhancement in the PL peak intensity with increasing temperature accompanies with red shift in its peak position.
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