Principle Investigator


Shuang Fang Lim, PhD

Assistant Professor

Physics Department

North Carolina State University

Mailing Address: Physics Department
North Carolina State University
2401 Stinson Drive, Riddick Hall 421
Raleigh, North Carolina 27695-8202

Office: Riddick Hall 258D

Lab: Riddick Hall 235, 237, 238, 264

Tel: 919-513-4827
Fax: 217-515-6538



  • 2004, Ph.D. in Physics, University of Cambridge, UK (Advisor: Sir Richard Friend, Franco Cacialli)
  • 1998, M.Sc. in Physics, National University of Singapore, Singapore (Advisor: Andrew Wee Thye Sen)
  • 1996, B.Sc. in Materials Science, National University of Singapore, Singapore


  • 08/2012 – present: Assistant Professor, Department of Physics, North Carolina State University.
  • 2010-2012: Research Assistant Professor, Department of Physics, North Carolina State University.
  • 2008-2010: Postdoctoral Research Associate, Department of Physics, North Carolina State University.
  • 2004-2008: Postdoctoral Research Associate, Department of Physics, Princeton University.

Positions Available

Postdoctoral Researchers

We are seeking 1 postdoc with experience in

1) Time-resolved spectroscopy

2) Biomedical applications

Graduate Students

We are seeking graduate students from all departments (engineering grad students are welcome!) interested in simulations, biomedical applications, time-resolved spectroscopy and nanofabrication.

Undergraduate Students

We welcome all undergraduate students interested in developing latent research skills in nano- bio- photonics.

Please send all queries to Dr. Shuang Fang Lim, email:
Shuang Fang Lim
Shuang Fang Lim Faculty


1. ‘Optical investigation of gold shell enhanced 25 nm diameter upconverted fluorescence emission’ K. Green, J. Wirth, S. F. Lim, Nanotechnology 27(13): 135201, FEB 2016.(
2.‘Multifunctional diagnostic, nanothermometer, and photothermal nano-devices’, K. Green, J. Wirth, M. O’Connor and S. F. Lim, 26 August 2015, Proc. SPIE 9584, Ultrafast Nonlinear Imaging and Spectroscopy III, 95840D.doi:10.1117/12.2188604.
3.‘Effective photothermal treatments for cancer’, K. Green and S. F. Lim, 25 August 2015, SPIE Newsroom. DOI: 10.1117/2.1201508.006064.
4. ‘Interference of ATP with the fluorescent probes YOYO-1 and YOYO-3 modifies the mechanical properties of intercalator-stained DNA confined in nanochannels’, M. Roushan, Z. Azad, S. F. Lim, H. Wang, R. Riehn, Microchimica Acta 182(7-8), 1561-1565, JUN 2015.
5. ‘Enhancement of single particle rare earth doped NaYF4: Yb, Er emission with a gold shell’, L. Li, K. Green, H. Hallen, S. F. Lim, Nanotechnology 26(2): 025101/1-9, JAN 2015.
6. ‘Probing transient protein-mediated DNA linkages using nanoconfinement’, M. Roushan, P. Kaur, A. Karpusenko, P. J. Countryman, C. P. Ortiz, S. F. Lim, H. Wang, R. Riehn, Biomicrofluidics 8(3): 034113/1-15, JUN 2014.(Feature Article)
7. ‘Chromatin modification mapping in nanochannels’, S. F. Lim, A. Karpusenko, D.E. Streng, R. Riehn, Biomicrofluidics 7(6): 064105/1-8, NOV 2013.( top 10 most downloaded articles from the journal from Jan-March, 2014)
8. ‘Near-field enhanced ultraviolet resonance Raman spectroscopy using aluminum bow-tie nano-antenna’, L. Li, S. F. Lim, A. A. Puretzky, R. Riehn, H. D. Hallen, Applied Physics Letters 101(11): 113116/1-4, SEP 2012.
9. ‘Fluctuation modes of nanoconfined DNA’. A. Karpusenko, J. H. Carpenter, C. , S. F. Lim, J. Pan, R. Riehn, Journal of Applied Physics 111(2): 024701-024708, JAN 2012.
10. ‘DNA Methylation Profiling in Nanochannels’. S. F. Lim, A. Karpusenko, J. J. Sakon, J. A. Hook, T. A. Lamar, R. Riehn, Biomicrofluidics 5(3): 034106-034114, JUL 2011.
11. ‘Density fluctuations dispersion relationship for a polymer confined to a nanotube’. J. H. Carpenter, A. Karpusenko, J. Pan, S. F. Lim, R. Riehn, Applied Physics Letters 98(25): 253704-253706, JUN 2011.
12. ‘Epigenetic Analysis of Chromatin in Nanochannels’, D. E. Streng, S. F. Lim, R. Riehn, Biophysical Journal, 98(3):600A-600A, JAN 2010.
13. ‘Particle size dependence of the dynamic photophysical properties of NaY4:Yb, Er nanocrystals’. S. F. Lim, W. S. Ryu, R. H. Austin, Optics Express 18(3): 2309-2316, FEB 2010.
14. ‘Nanofabricated upconversion nanoparticles for photodynamic therapy’. B. Ungun, R. K. Prud’homme, S. J. Budijono, J. Shan, S. F. Lim, Y. Ju, R. H. Austin, Optics Express 17(1): 80-86 JAN 2009.
15. ‘Stretching chromatin through confinement’. D. E. Streng, S. F. Lim , J. Pan , A. Karpusenka, R. Riehn, Lab Chip 9: 2772 – 2774 AUG 2009.
16. ‘Upconverting nanophosphors for bioimaging’. S. F. Lim, R. Riehn, C-K Tung, W. S. Ryu, R. Zhuo, J. Dalland, R. H. Austin, Nanotechnology 20(40): 405701 SEP 2009.
17. ‘The Sackler Colloqium on Promise and Perils In Nanotechnology for Medicine’. R. H. Austin, S. F. Lim, PNAS 105(45): 17217-1722 NOV 2008.
18. ‘In vivo and scanning electron microscopy imaging of upconverting nanophosphors in Caenorhabditis elegans’. S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. K. Tung, D. Tank, R.H. Austin, Nano Letters 6 (2): 169-174 FEB 2006. Article featured in Analytical Chemistry 78(7): 2082 APR 2006. (More than 450 citations.)(Feature article in Analytical Chemistry 78(7): 2082 APR 2006).
19. ‘Restriction mapping in nanofluidic devices’. R. Riehn, M. Lu, Y.M. Wang, S. F. Lim, E.C. Cox, R.H. Austin, PNAS 102 (29): 10012-10016 JULY 2005
20. ‘Suppression of green emission in a new class of blue-emitting polyfluorene copolymers with twisted biphenyl moieties’. S. F. Lim, F. Cacialli, R.H. Friend, I.D. Rees, J. Li, Y-G. Ma, K. Robinson, A.B. Holmes, D. Beljonne, E. Hennebicq, F. Cacialli, Advanced Functional Materials, 15 (6): 981-988 JUN 2005.
21. ‘Synthesis and luminescence properties of three novel polyfluorene copolymers’. A. Charas, J. Morgado, J. M. G. Martinho, L. Alcacer, S. F. Lim, R. H. Friend, F. Cacialli, Polymer, 44 (6): 1843-1850 MAR 2003
22. ‘Understanding dark spot formation and growth in organic light-emitting devices by controlling pinhole size and shape’. S. F. Lim, W. Wang, S. J. Chua, Advanced Functional Materials, 12 (8): 513-518 AUG 2002.
23. ‘Bubble formation and growth in organic light-emitting diodes composed of a polymeric emitter and a calcium cathode’. W. Wang, S. F. Lim, S. J. Chua, Journal of Applied Physics 91 (9): 5712-5715. MAY 2002.
24. ‘Design of luminescent polymers for LEDs’, A. B. Holmes, A. D. Bond, J. E. Davies, C. Fischmeister, J. Frey, U. Hennecke, J. Li, Y. Ma, R. E. Martin, I. D. Rees, K. Robinson, T. Sano, F. Cacialli, S. F. Lim, R. H. Friend, Mat. Res. Soc. Symp. Proc., 708: BB5.2.1-BB5.2.11 2002.
25. ‘A new family of polyfluorene copolymers for light emitting devices’, A. B. Holmes, T. Sano, C. Fischmeister, J. Frey, U. Hennecke, C. S. Tuan, B. S. Chuah, Y. G. Ma, R. E. Martin, I. D. Rees, L. Jian, N. R. Feeder, A. D. Bond, F. Cacialli, S. F. Lim, R. H. Friend, Proceedings of the Society of Photo-Optical Instrumentation Engineers (SPIE), 4464: 42-48 2002.
26. ‘Design of conjugated polymers for light emitting diodes’, A. B. Holmes, I. D. Rees, Y. Ma, R. E. Martin, C. Fischmeister, T. Sano, U. Hennecke, S. F. Lim, F. Cacialli, R. H. Friend, Abstracts of papers of the American Chemical Society 222: 270-POLY Part 2 AUG 2001.
27. ‘Morphological and electrical properties of indium tin oxide films prepared at a low processing temperature for flexible organic light-emitting devices’, F. R. Zhu, K. Zhang, B. L. Low, S. F. Lim, S. J. Chua, Materials Science and Engineering B-Solid State Materials for Advanced Technology 85 (2-3): 114-117 Sp. Iss. SI AUG 22 2001.
28. ‘Degradation of organic light-emitting devices due to formation and growth of dark spots’, S. F. Lim, W. Wang, S. J. Chua, Materials Science and Engineering B-Solid State Materials for Advanced Technology 85 (2-3): 154-159 Sp. Iss. SI AUG 22 2001.
29. ‘Influence of electrical stress voltage on cathode degradation of organic light-emitting devices’. L. Ke, S. J. Chua, S. F. Lim, Journal of Applied Physics, 90 (2): 976-979 JUL 15 2001.
28. ‘Organic light-emitting device dark spot growth behavior analysis by diffusion reaction theory’. L. Ke, S. F. Lim, S. J. Chua. Journal of Polymer Science Part B-Polymer Physics 39 (14): 1697-1703 JUL 15 2001.
30. ‘Correlation between dark spot growth and pinhole size in organic light emitting diodes’. S. F. Lim, L. Ke, W. Wang, S. J. Chua, Applied Physics Letters, 78 (15): 21162118 APR 9 2001.
31. ‘Growth of carbon nitride thin films by radio-frequency-plasma-enhanced chemical vapor deposition at low temperatures’. S. F. Lim, A. T. S. Wee, J. Lin, D. H. C. Chua, K. L. Tan, Journal of Materials Research, 14 (3): 1153-1159 MAR 1999.
32. ‘Crystalline carbon nitride deposition by r.f.-PECVD using a C2H4-NH3-H2 source gas mixture’. S. F. Lim, A. T. S. Wee, J. Lin, D. H. C. Chua, Surface and Interface Analysis, 28 (1): 212-216 AUG 1999.
33. ‘On the nature of carbon nitride nanocrystals formed by plasma enhanced chemical vapor deposition and rapid thermal annealing’. S. F. Lim, A. T. S. Wee, J. Lin, D. H. C. Chua, C. H. A. Huan, Chemical Physics Letters, 306 (1-2): 53-56 JUN 4 1999.
34. ‘Substrate influence on the formation of FeSi and FeSi2 films from cis-Fe(SiCl3)(2)(CO)(4) by LPCVD’. L. Luo, C. E. Zybill, H. G. Ang, S. F. Lim, D. H. C. Chua, J. Lin, A. T. S. Wee, K. L. Tan, Thin Solid Films, 325 (1-2): 87-91 JUL 18 1998.

Book Chapters
1. ‘Nanochannels for Genomic DNA Analysis: The Long and the Short of It’.
R. Riehn, W. Reisner, J. O. Tegenfeldt, Y. M. Wang, C. –K. Tung, S. F. Lim, E. C. Cox, J. C. Sturm, K. Morton, S. Y. Chou, R. H. Austin. in Liu, R.H. and Lee, A.P. (eds.) “Integrated Biochips for DNA Analysis” , Landes Bioscience, Austin, TX and Springer Science+Business Media, New York, NY, 2007, pgs 151-186.
2. Upconverting nanoparticle based multi-functional nanoplatform for enhanced photodynamic therapy: Promises and Perils”, S.F. Lim and R. H. Austin. In M. R. Hamblin and P. Avci (eds.) “Applications of Nanoscience in Photomedicine”, Woodhead Publishing Series in Biomedicine, AUG 2014.

Invited Talks

1. ‘Upconverting sub-10 nm sized nanophosphors in bioimaging’ at the Nanomaterials in Medicine Sackler Colloquium, Washington D.C., Feb 2007.
2. ‘Upconversion nanophosphors as biosensors and biotherapeutic agents’ at the NCSU MSE Seminar series, 6 September 2011.
3. ‘Engineering upconverting nanophosphors as biosensors and biotherapeutic agents’ at the APS 2012 Spring Meeting.
4. ‘Upconversion nanophosphors as biosensors and biotherapeutic agents’ at the East Carolina University Physics Colloquium, 12 October 2012.
5. ‘Upconversion nanophosphors as biosensors and biotherapeutic agents’ at the South Dakota School of Mines & Technology Physics Colloquium, 14 March 2013.
6. ‘Upconversion nanophosphors as biosensors and biotherapeutic agents’ at the CC3DMR2014 conference in Seoul, South Korea, 24 June 2014.
7. ‘Upconversion nanophosphors as biosensors and biotherapeutic agents’ at the University of Tehran, Iran, Physics Colloquium, 13 Oct 2014.
8. ‘Upconversion nanophosphors as biosensors and biotherapeutic agents’ at Sharif University, Iran, Physics Colloquium, 15 Oct 2014.
9. ‘Upconversion nanophosphors as biosensors and biotherapeutic agents’ at IPM Institute for research in Fundamental Sciences, Iran, 14 Oct 2014.
10. ‘Upconversion nanophosphors as biosensors and biotherapeutic agents’ at the University of North Carolina at Wilmington Physics Colloquium, 20 March 2015.
11. ‘Upconversion nanophosphors as biosensors and biotherapeutic agents’ at Argonne National Labs at APS/CNM Users Meeting Nanophotonics Workshop, 12 May 2015.
12. ‘Multifunctional diagnostic, nanothermometer, and photothermal nanodevices’ at SPIE Optics and Photonics conference, San Diego, 9 August 2015.
13. ‘Nanophotonics – From Simulations, Photophysics, to Biomedical Devices’ at NC A&T State University, Physics Colloquium, 29 Feb 2016.


Postdoctoral Research Associate


Janina Wirth (Since Jan 2015)

Janina is working on nanofabrication and AFM, SEM, and dark field scattering measurements of plasmonic metallic nanostructures.

Graduate Students


Kory Green (Since 2013)

Kory is working on the synthesis and single particle optical and thermal characterization of upconverting nanoparticles.


Maedeh Heidarpouroushan (Graduated Dec 2015)

Maedeh has been working on integrating upconverting nanoparticle probes in a microfluidic array sensor.


Sara Jafaripazoki (Since Jan 2016)

Sara is working on real time DNA and aptamer sensing in a microfluidic device.

Undergraduate Students


Megan O’Connor (Electrical and Computer Engineering, NCSU)

Megan performs finite element calculations of the excitation and emission of upconverting nanoparticles and other plasmonic nanostructures.


Andrew Tong (Biomedical Engineering, NCSU)

Andrew is working on biological surface modification for microarrays.


Facilities & Equipment

The Lim lab has two wet labs, one large and one small, with two dedicated fume hoods, for nanoparticle synthesis and functionalization and also handling of biologicals. The wetlab is climate controlled for biological work, with ruby lights to discourage degradation of fluorescently tagged DNA/proteins. The labs have other supporting equipment such as fridges (-80oC, -20oC and 4oC), centrifuges (benchtop and refrigerated), ultrapure water system, autoclave, vortexes (single and multi-), ultrasonic bath and probe tip sonicator, thermo-mixers and pipettors.


Our optical lab is equipped with a high-end inverted microscope setup with accessories such as a PI Nano piezo stage, a half-meter monochromator, and an Andor Neo sCMOS camera, for single-molecule fluorescence, DIC, and dark field microscopy. A tunable Nd:YAG laser and a number of diode lasers are coupled into the microscope. Single particle spectra and time-resolved decay can be recorded using a series of photon detectors optimized for different wavelength ranges. We have photon detectors from Hamamatsu H7421 for green detection, an Excelitas single photon counting unit for red detection, and a Hamamatsu NIR- PMT Module (H10330A-75) for NIR detection.








We are working on understanding the physics of nanophotonic materials and their applications in biosensing and solar cell devices. We optimize our proposed nanostructures with predictive finite element modeling, and perform correlated structural and optical single nanoparticle spectroscopy to explore the link between nanoparticle size/geometry/orientation and its corresponding optical property. As such, we use analytical tools (AFM, fluorescence microscopy, single particle time-resolved spectroscopy, SEM, TEM) and other experimental methods in order to elucidate the nanostructure effect on photophysical mechanisms.
Fig. 1 TEM image of fabricated upconverting nanoparticles.

We further develop these nanomaterials for biosensing in microfluidic systems, as single molecule nanoprobes, and potential enhancements to solar cell devices.


1) Enhancement of fluorescence with Coupling to Metallic Nanofeatures


Coupling of metallic nanostructures to fluorophores results in enhanced excitation absorption and fluorescence emission. We perform structurally correlated single particle upconverted fluorescent spectra measurements and time-resolved decay to investigate the influence of metallic nanostructures such as gold shells, gold nanorods and gold mirrors. The nanostructures are optimized with finite element modeling and nanofabricated. We corroborate our experimental results with further finite element calculations to develop a physical model. In the figure shown, the calculations show a spatial dependence of the electric field at four combinations of incident excitation light direction, excitation polarization and nanocrystal orientation. The most strongly enhanced configurations for fluorescence are the ones with light incident perpendicular to the top face of the hexagonal crystal shape and polarized either from apex to apex or the flat to flat sides (Fig. 2).

Fig. 2 Calculated electric field of a single upconverting nanoparticle coated with a gold shell. Four different relative configurations between the incident light direction, excitation polarization and nanocrystal orientation is shown. (a) The light is incident from above the plate with polarization apex-apex (the red ones). (b) The incident light is polarized vertically and enters towards the red apex. (c) The light incident from above is polarized face-face (perpendicular to the red faces). (d) The light incident towards the red face is polarized vertically.


2) Single Particle Thermal Sensing.


Thermal sensing at the cellular level has direct implications in inferring the metabolic status, pathology and physiology, especially of a cancer cell.

UCNPs have also been shown to not affect cellular processes, and are far less sensitive to physiological changes such as salt concentration, and pH, while monitoring cellular temperatures. The nanothermometer properties in UCNPs are attributed to the emission of the Er3+ rare earth ion, specifically the intensity ratio (RHS) of the 2H11/2 to 4I15/2 (525 nm) over 4S3/2 to 4I15/2 (545 nm) transitions. The relative intensity of the two green bands can be understood by considering the energy separation between the nearest excited states Er: 2H11/2 and Er: 4S3/2, which is only several hundred wavenumbers. Thus, the population distribution on Er: 2H11/2 and Er: 4S3/2 should be dominated both by thermal distribution and nonradiative relaxation. Therefore, the population of the Er: 2H11/2 level varies as a function of the Boltzmann’s distribution. This ratio is inversely proportional to the temperature range relevant to most biological systems.

We investigate the influence of gold nanorods (AuNRs) attachment on upconverted fluorescence and time-resolved decay (Fig. 3).

Fig. 3 (A) AFM of a single UCNP with attached gold AuNRs, (B) Corresponding time-resolved decay at 545 nm and 650 nm of UCNP-AuNRs nanostructure.

3) Biosensing


Our device (Fig. 4) uses printed capture DNA oligomer spots to immobilize target DNA and other diagnostic proteins on a microarray, and detect their presence by binding of probe DNA coupled UCNPs, referred to as a sandwich assay. The binding of target DNA will be detected on microarray spots with integrated photodetectors. The combination of photodetector, micro-fluidic
 handling, and NIR excited UCNP probes enables streamlined protocols that circumvents the need for a microarray reader, thus reducing costs and increasing portability. Furthermore, micro-fluidic handling and detection under flow, cuts the overall detection time to under 15 minutes as compared to the traditional flow process with hour-long hybridization time.


Fig. 4 Polydimethylsiloxane (PDMS) sealed microarray microfluidic chip.

4) Funding

Funding: National Science Foundation CBET (1067508, PI Lim) and NC State Startup Funds.


5) Collaborators

Dr. Hans Hallen, Physics, NCSU.


Dr. Robert Riehn, Physics, NCSU.


Dr. Hong Wang, Physics, NCSU.


Dr. Frank Scholle, Microbiology, NCSU.


Dr. Sergei Vinogradov, Perelman School of Medicine, University of Pennsylvania