Browsing by Author "Lin, T. N."

Now showing 1 - 9 of 9

Distance dependence of energy transfer from InGaN quantum wells to graphene oxide
(2013-08-01)
Lin, T. N.
;
Huang, L. T.
;
Shu, G. W.
;
Yuan, C. T.
;
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.
;
Cai, K. B.
;
Chang, L. Y.
;
Chen, P. W.
;
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.
;
Chiu, C. H.
;
Huang, L. T.
;
Lin, T. N.
;
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.
;
Lin, C. C.
;
Lin, H. T.
;
Lin, T. N.
;
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
Enhancement of light emission in GaAs epilayers with graphene quantum dots
(2015-01-01)
Lin, T. N.
;
Chih, K. H.
;
Cheng, M. C.
;
Yuan, C. T.
;
Hsu, C. L.
A green and one-step synthesis of graphene quantum dots (GQDs) has been implemented using pulsed laser ablation from aqueous graphene. The synthesized GQDs are able to enhance the photoluminescence (PL) of GaAs epilayers after depositing them on the GaAs surface. An enhancement of PL intensity of a factor of 2.8 has been reached at a GQD concentration of 1.12 mg ml(-1). On the basis of the PL dynamics, the PL enhancement in GaAs is interpreted by the carrier transfer from GQDs to GaAs due to the work function difference between them.
Hybrid Dendrimer/Semiconductor Nanostructures with Efficient Energy Transfer via Optical Waveguiding
(2015-03-05)
Lin, T. N.
;
Huang, J. C.
;
Shen, J. L.
;
Chu, C. M.
;
Yeh, J. M.
In this study, we demonstrated a nonradiative energy transfer between InGaN quantum wells (QWs) and polyamidoamine (PAMAM) dendrimers through optical waveguiding by detecting a reduction in the photoluminescence lifetime. The maximum energy transfer efficiency of this system is similar to 72%, which is promising for sensor applications. The energy transfer efficiency depends on the distance between the InGaN QWs and PAMAM dendrimers by a factor of 1/d(2), revealing layer-to-layer dipole interactions. Upon increasing the generation of PAMAM dendrimers, the transfer energy efficiency increases exponentially, which can be explained by the increased surface coverage for the higher generation.
Influence of pulsed laser annealing on the optical properties of ZnO nanorods
(2012-08-01)
Lin, T. N.
;
Huang, C. P.
;
Shu, G. W.
;
Shen, J. L.
;
Hsiao, C. S.
"The effect of pulsed laser annealing (PLA) on the photoluminescence (PL) properties of ZnO nanorods was investigated. As the fluence of pulsed laser increases, the UV PL in ZnO nanorods shows a general increasing trend, except at a range of fluences from 10 to 70?mJ/cm2. It is found that the treatment with the PLA at the fluence of 70?mJ/cm2 leads to a larger improvement of crystalline properties than that with rapid thermal annealing (RTA). The relationship between PL intensity and fluence of pulsed lasers can be well explained by a combination of the deterioration in surface crystallinity and the increased donor densities after PLA."
Photo-induced Doping in GaN Epilayers with Graphene Quantum Dots
(2016-03-18)
Lin, T. N.
;
Inciong, M. R.
;
Santiago, S. R. M. S.
;
Yeh, T. W.
;
Yang, W. Y.
We demonstrate a new doping scheme where photo-induced carriers from graphene quantum dots (GQDs) can be injected into GaN and greatly enhance photoluminescence (PL) in GaN epilayers. An 8.3-fold enhancement of PL in GaN is observed after the doping. On the basis of time-resolved PL studies, the PL enhancement is attributed to the carrier transfer from GQDs to GaN. Such a carrier transfer process is caused by the work function difference between GQDs and GaN, which is verified by Kelvin probe measurements. We have also observed that photocurrent in GaN can be enhanced by 23-fold due to photo-induced doping with GQDs. The improved optical and transport properties from photoinduced doping are promising for applications in GaN-based optoelectronic devices.
Waveguide based energy transfer with gold nanoclusters for detection of hydrogen peroxide
(2014)
Lin, T. N.
;
Chang, Y. L.
;
Shu, G. W.
;
Yuan, C. T.
;
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.