Franky So

Walter and Ida Freeman Distinguished Professor

  • Engineering Building I (EB1) 3070B

Franky So started his career as a research scientist working on polymer optical modulators at Hoechst Celanese Research Division. In 1993, he joined Motorola and then became the Head of the OLED research group. In 2001, and he joined OSRAM Opto Semiconductors and became the Head of OLED Research. He joined the University of Florida in 2005 and became the Rolf E. Hummel Professor in Electronic Materials in the Department of Materials Science and Engineering at the University of Florida. In 2015, he joined the Department of Materials Science and Engineering at the North Carolina State University where he is currently the Walter and Ida Freeman Distinguished Professor. While at Motorola, he was named the Distinguished Innovator and Master Innovator. He was the recipient of the DOE Solid State Lighting Program Significant Achievement Awards. Dr. So holds 80 issued patents and has published more than 160 peer-reviewed articles with a Google H-index of 63. He is the Editor-in-Chief of the journal Materials Science and Engineering Reports and serves as an Associate Editor for IEEE Journal of Photovoltaics, IEEE Journal of Display Technology, SPIE Journal of Photonic Technology and Organic Electronics. So is a Distinguished Lecturer of the IEEE Photonics Society, a Charter Fellow of the National Academy of Inventors, a Fellow of IEEE, OSA and SPIE.

So’s current research focus is on electronics properties and photophysics of organic semiconductors and quantum dots used for OLEDs, solar cells, photodetectors, sensors and transistors. His recent works include: use of corrugated structures to fabricate OLEDs and perovskite solar cells, charge transport, injection and charge transfer excitons in organic semiconductors, dielectric properties of polymer-fullerene blends for photovoltaics, vertical permeable metal base transistors, vertical field effect transistors, PbS quantum dots photodetectors and phototransistors, and ferroelectric transistors.



Ph.D. 1991

Electrical Engineering

University of Southern California

M.S. 1982

Materials Science

Massachusetts Institute of Technology

B.A. 1979


Hamilton College


Donor Conjugated Polymers with Polar Side Chain Groups: The Role of Dielectric Constant and Energetic Disorder on Photovoltaic Performance
Xu, B., Yi, X., Huang, T.-Y., Zheng, Z., Zhang, J., Salehi, A., … Reynolds, J. R. (2018), ADVANCED FUNCTIONAL MATERIALS, 28(46).
Every atom counts: Elucidating the fundamental impact of structural change in conjugated polymers for organic photovoltaics
Lo, C. K., Gautam, B. R., Selter, P., Zheng, Z. L., Oosterhout, S. D., Constantinou, I., … Reynolds, J. R. (2018), Chemistry of Materials, 39(9), 2995–3009.
Flexoelectricity in a metal/ferroelectric/semiconductor heterostructure
Huang, S. J., Yau, H. M., Yu, H., Qi, L., So, F., Dai, J. Y., & Jiang, X. N. (2018), AIP Advances, 8(6).
Manipulating refractive index in organic light-emitting diodes
Salehi, A., Chen, Y., Fu, X. Y., Peng, C., & So, F. (2018), ACS Applied Materials & Interfaces, 10(11), 9595–9601.
Sub-band gap turn-on near-infrared-to-visible up-conversion device enabled by an organic-inorganic hybrid perovskite photovoltaic absorber
Yu, H., Cheng, Y. H., Li, M. L., Tsang, S. W., & So, F. (2018), ACS Applied Materials & Interfaces, 10(18), 15920–15925.
langmuir-blodgett thin films of diketopyrrolopyrrole-based amphiphiles
Lo, C. K., Wang, C. Y., Oosterhout, S. D., Zheng, Z. L., Yi, X. P., Fuentes-Hernandez, C., … Reynolds, J. R. (2018), ACS Applied Materials & Interfaces, 10(14), 11995–12004.
18% high-efficiency air-processed perovskite solar cells made in a humid atmosphere of 70% RH
Cheng, Y. H., Xu, X. W., Xie, Y. M., Li, H. W., Qing, J., Ma, C. Q., … Tsang, S. W. (2017), Solar RRL, 1(9).
Comparing non-fullerene acceptors with fullerene in polymer solar cells: a case study with FTAZ and PyNCTAZ
Bauer, N., Zhang, Q. Q., Zhao, J. B., Ye, L., Kim, J. H., Constantinou, I., … You, W. (2017), Journal of Materials Chemistry A, 5(10), 4886–4893.
Flexible inorganic ferroelectric thin films for nonvolatile memory devices
Yu, H., Chung, C. C., Shewmon, N., Ho, S., Carpenter, J. H., Larrabee, R., … So, F. (2017), Advanced Functional Materials, 27(21).
Highly efficient organic light-emitting diode using a low refractive index electron transport layer
Salehi, A., Ho, S., Chen, Y., Peng, C., Yersin, H., & So, F. (2017), Advanced Optical Materials, 5(11).
In search of deeper blues: Trans-N-heterocyclic carbene platinum phenylacetylide as a dopant for phosphorescent OLEDS
Bullock, J. D., Salehi, A., Zeman, C. J., Abboud, K. A., So, F., & Schanze, K. S. (2017), ACS Applied Materials & Interfaces, 9(47), 41111–41114.
Organic molecular light-emitting materials and devices
So, F., & Shi, J. M. (2017), Introduction to Organic Electronic and Optoelectronic Materials and Devices, 2nd Edition, 363–385.
Probing the emission zone length in organic light emitting diodes via photoluminescence and electroluminescence degradation analysis
Peng, C., Salehi, A., Chen, Y., Danz, M., Liaptsis, G., & So, F. (2017), ACS Applied Materials & Interfaces, 9(47), 41421–41427.
Strong polymer molecular weight-dependent material interactions: Impact on the formation of the polymer/fullerene bulk heterojunction morphology
Kim, J. H., Gadisa, A., Schaefer, C., Yao, H. F., Gautam, B. R., Balar, N., … Ade, H. (2017), Journal of Materials Chemistry A, 5(25), 13176–13188.
Transparent indium-tin oxide/indium-gallium-zinc oxide Schottky diodes formed by gradient oxygen doping
Ho, S., Yu, H., & So, F. (2017), Applied Physics Letters, 111(21).
Ultraviolet-ozone surface modification for non-wetting hole transport materials based inverted planar perovskite solar cells with efficiency exceeding 18%
Xu, X. W., Ma, C. Q., Cheng, Y. H., Xie, Y. M., Yi, X. P., Gautam, B., … Tsang, S. W. (2017), Journal of Power Sources, 360, 157–165.
Using ultralow dosages of electron acceptor to reveal the early stage donor-acceptor electronic interactions in bulk heterojunction blends
Ho, C. H. Y., Cheung, S. H., Li, H. W., Chiu, K. L., Cheng, Y. H., Yin, H., … So, S. K. (2017), Advanced Energy Materials, 7(12).
Utilizing Forster resonance energy transfer to extend spectral response of PCDTBT:PCBM solar cells
Klump, E., Constantinou, I., Lai, T. H., & So, F. (2017), Organic Electronics, 42, 87–92.
effect of polymer-fullerene interaction on the dielectric properties of the blend
Constantinou, I., Yi, X. P., Shewmon, N. T., Klump, E. D., Peng, C., Garakyaraghi, S., … So, F. (2017), Advanced Energy Materials, 7(13).
Charge photogeneration in organic photovoltaics: Role of hot versus cold charge-transfer excitons
Gautam, B. R., Younts, R., Li, W. T., Yan, L., Danilov, E., Klump, E., … Gundogdu, K. (2016), Advanced Energy Materials, 6(1).
Corrugated organic light emitting diodes using low T-g electron transporting materials
Peng, C., Liu, S. Y., Fu, X. Y., Pan, Z. X., Chen, Y., So, F., & Schanze, K. S. (2016), ACS Applied Materials & Interfaces, 8(25), 16192–16199.
Degradation study of organic light-emitting diodes with solution-processed small molecule phosphorescent emitting layers
Liu, S. Y., Peng, C., Cruz, A., Chen, Y., & So, F. (2016), Journal of Materials Chemistry C, 4(37), 8696–8703.
Efficiency roll-off in blue emitting phosphorescent organic light emitting diodes with carbazole host materials
Xiang, C. Y., Fu, X., Wei, W., Liu, R., Zhang, Y., Balema, V., … So, F. (2016), Advanced Functional Materials, 26(9), 1463–1469.
Evidence of molecular structure dependent charge transfer between isoindigo-based polymers and fullerene
Lai, T. H., Constantinou, I., Grand, C. M., Klump, E. D., Baek, S., Hsu, H. Y., … So, F. (2016), Chemistry of Materials, 28(7), 2433–2440.
Formation of perovskite heterostructures by ion exchange
Shewmon, N. T., Yu, H., Constantinou, I., Klump, E., & So, F. (2016), ACS Applied Materials & Interfaces, 8(48), 33273–33279.
High-gain infrared-to-visible upconversion light-emitting phototransistors
Yu, H., Kim, D., Lee, J., Baek, S., Lee, J., Singh, R., & So, F. (2016), Nature Photonics, 10(2), 129–.
Inorganic UV-visible-SWIR broadband photodetector based on monodisperse PbS nanocrystals
Lee, J. W., Kim, D. Y., Baek, S., Yu, H., & So, F. (2016), Small (Weinheim An Der Bergstrasse, Germany), 12(10), 1328–1333.
Interface effect on efficiency loss in organic light emitting diodes with solution processed emitting layers
Ho, S. H., Chen, Y., Liu, S. Y., Peng, C., Zhao, D. W., & So, F. (2016), Advanced Materials Interfaces, 3(19).
Perovskite solar cells on corrugated substrates with enhanced efficiency
Luo, Y., Liu, S. Y., Barange, N., Wang, L., & So, F. (2016), Small (Weinheim An Der Bergstrasse, Germany), 12(46), 6346–6352.
Photodegradation of metal oxide interlayers in polymer solar cells
Constantinou, I., Shewmon, N. T., Lo, C. K., Deininger, J. J., Reynolds, J. R., & So, F. (2016), Advanced Materials Interfaces, 3(23).
Solution-processed copper oxide interlayers for broadband PbS quantum-dot photodiodes
Yu, H., Liu, S., Baek, S., Kim, D. Y., Dong, C., & So, F. (2016), Journal of Materials Chemistry C, 4(47), 11205–11211.
Structure-property relationships directing transport and charge separation in isoindigo polymers
Grand, C., Baek, S., Lai, T. H., Deb, N., Zajaczkowski, W., Stalder, R., … Reynolds, J. R. (2016), Macromolecules, 49(11), 4008–4022.
Vertical organic field-effect transistors for integrated optoelectronic applications
Yu, H., Dong, Z. P., Guo, J., Kim, D., & So, F. (2016), ACS Applied Materials & Interfaces, 8(16), 10430–10435.
Effect of polymer side chains on charge generation and disorder in PBDTTPD solar cells
Constantinou, I., Lai, T. H., Klump, E. D., Goswami, S., Schanze, K. S., & So, F. (2015), ACS Applied Materials & Interfaces, 7(48), 26999–27005.
Origin of sub-bandgap electroluminescence in organic light-emitting diodes
Xiang, C. Y., Peng, C., Chen, Y., & So, F. (2015), Small (Weinheim An Der Bergstrasse, Germany), 11(40), 5439–5443.
Solid-state lighting: photonics and technologies
Tansu, N., & So, F. (2015), Journal of Photonics for Energy, 5.
The role of photonics in energy
Kafafi, Z. H., Martin-Palma, R. J., Nogueira, A. F., O’Carroll, D. M., Pietron, J. J., Samuel, I. D. W., … Tsakalakos, L. (2015), Journal of Photonics for Energy, 5.

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