Browsing by Author "Lin, C. A. J."

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Distance dependence of energy transfer from InGaN quantum wells to graphene oxide
(2013-08-01)
Lin, T. N.
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Huang, L. T.
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Shu, G. W.
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Yuan, C. T.
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Shen, J. L.
We report the distance-dependent energy transfer from an InGaN quantum well to graphene oxide (GO) by time-resolved photoluminescence (PL). A pronounced shortening of the PL decay time in the InGaN quantum well was observed when interacting with GO. The nature of the energy-transfer process has been analyzed, and we find the energy-transfer efficiency depends on the 1/d(2) separation distance, which is dominated by the layer-to-layer dipole coupling. (C) 2013 Optical Society of America
Eco-friendly luminescent solar concentrators with low reabsorption losses and resistance to concentration quenching based on aqueous-solution-processed thiolate-gold nanoclusters
(2017-09-15)
Huang, H. Y.
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Cai, K. B.
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Chang, L. Y.
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Chen, P. W.
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Lin, T. N.
Heavy-metal-containing quantum dots (QDs) with engineered electronic states have been served as luminophores in luminescent solar concentrators (LSCs) with impressive optical efficiency. Unfortunately, those QDs involve toxic elements and need to be synthesized in a hazardous solvent. Recently, biocompatible, eco-friendly gold nanoclusters (AuNCs), which can be directly synthesized in an aqueous solution, have gained much attention for promising applications in 'green photonics'. Here, we explored the solid-state photophysical properties of aqueoussolution- processed, glutathione-stabilized gold nanoclusters (GSH-AuNCs) with a ligand-tometal charge-transfer (LMCT) state for developing 'green' LSCs. We found that such GSH-AuNCs exhibit a large Stokes shift with almost no spectral overlap between the optical absorption and PL emission due to the LMCT states, thus, suppressing reabsorption losses. Compared with GSH-AuNCs in solution, the photoluminescence quantum yields (PL-QYs) of the LSCs can be enhanced, accompanied with a lengthened PL lifetime owing to the suppression of non-radiative recombination rates. In addition, the LSCs do not suffer from severe concentration-induced PL quenching, which is a common weakness for conventional luminophores. As a result, a common trade-off between light-harvesting efficiency and solid-state PL-QYs can be bypassed due to nearly-zero spectral overlap integral between the optical absorption and PL emission. We expect that GSH-AuNCs hold great promise for serving as luminophores for 'green' LSCs by further enhancing solid-state PL-QYs.
Efficient energy transfer from InGaN quantum wells to Ag nanoparticles
(2013)
Shu, G. W.
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Chiu, C. H.
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Huang, L. T.
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Lin, T. N.
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Yang, C. C.
Nonradiative energy transfer from an InGaN quantum well to Ag nanoparticles is unambiguously demonstrated by the time-resolved photoluminescence. The distance dependence of the energy transfer rate is found to be proportional to 1/d(3), in good agreement with the prediction of the dipole interaction calculated from the Joule losses in acceptors. The maximum energy-transfer efficiency of this energy transfer system can be as high as 83%.
Energy transfer from InGaN quantum wells to Au nanoclusters via optical waveguiding
(2011-03-14)
Shu, G. W.
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Lin, C. C.
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Lin, H. T.
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Lin, T. N.
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Shen, J. L.
We present the first observation of resonance energy transfer from InGaN quantum wells to Au nanoclusters via optical waveguiding. Steady-state and time-resolved photoluminescence measurements provide conclusive evidence of resonance energy transfer and obtain an optimum transfer efficiency of similar to 72%. A set of rate equations is successfully used to model the kinetics of resonance energy transfer. (C) 2011 Optical Society of America
Improving Performance of InGaN/GaN Light-Emitting Diodes and GaAs Solar Cells Using Luminescent Gold Nanoclusters
(2009)
Yang, M. D.
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Wu, S. W.
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Shu, G. W.
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Wang, J. S.
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Shen, J. L.
We studied the optoelectronic properties of the InGaN/GaN multiple-quantum-well light emitting diodes (LEDs) and single-junction GaAs solar cells by introducing the luminescent Au nanoclusters. The electroluminescence intensity for InGaN/GaN LEDs increases after incorporation of the luminescent Au nanoclusters. An increase of 15.4% in energy conversion efficiency is obtained for the GaAs solar cells in which the luminescent Au nanoclusters have been incorporated. We suggest that the increased light coupling due to radiative scattering from nanoclusters is responsible for improving the performance of the LEDs and solar cells. Copyright (C) 2009 M. D. Yang et al.
Interrelation of transport and optical properties in gold nanoclusters
(2010-09-20)
Shu, G. W.
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Chen, T. Y.
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Shen, J. L.
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Lin, C. A. J.
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Chang, W. H.
Temperature dependence of the electrical conductivity and photoluminescence (PL) in Au nanoclusters (NCs) is investigated. The correlation of the conductivity and PL in Au NCs at different temperatures is evident: (i) for T < 50 K, both the conductivity and PL intensity decrease with temperature, which suggests thermal structural fluctuations; (ii) for 50 K < T < 90 K, conductivity and PL are explained by variable range hopping; (iii) for 90 K < T < 170 K, simple thermal activated hopping dominates in conductivity, with a rate-equation model proposed to analyze the carrier transfer in PL. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3491288]
Interrelation of transport and optical properties in gold nanoclusters
(2010-09-20)
Shu, G. W.
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Chen, T. Y.
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Shen, J. L.
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Lin, C. A. J.
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Chang, W. H.
Temperature dependence of the electrical conductivity and photoluminescence (PL) in Au nanoclusters (NCs) is investigated. The correlation of the conductivity and PL in Au NCs at different temperatures is evident: (i) for T < 50 K, both the conductivity and PL intensity decrease with temperature, which suggests thermal structural fluctuations; (ii) for 50 K < T < 90 K, conductivity and PL are explained by variable range hopping; (iii) for 90 K < T < 170 K, simple thermal activated hopping dominates in conductivity, with a rate-equation model proposed to analyze the carrier transfer in PL. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3491288]
Waveguide based energy transfer with gold nanoclusters for detection of hydrogen peroxide
(2014)
Lin, T. N.
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Chang, Y. L.
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Shu, G. W.
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Yuan, C. T.
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Shen, J. L.
H2O2 detection that uses fluorescence resonance energy transfer from InGaN quantum wells to Au nanoclusters via optical waveguiding has been developed. Steady and time-resolved photoluminescence studies have been used to demonstrate the waveguide-based energy transfer. H2O2 detection is achieved by the quenching of the red emission from Au nanoclusters. Advantages of the sensing technique include the capability of visual detection and large area analysis.