Qibing Pei is
professor of materials science and engineering specializing in synthetic
polymers. He worked successively as a senior chemist at UNIAX Corporation,
Santa Barbara, CA, which was later merged into DuPont Display, a senior
chemist at Imation Corporation, Santa Paul, MN, and a senior research
engineer at SRI International, Menlo Park, CA. He has developed a number of
electronic and electroactive polymers for applications in electro-optic and
electro-mechanical devices, including light emitting diodes, polymer light
emitting electrochemical cells, electroactive polymer artificial muscles,
and biologically-inspired robots. His research interests cover a wide range
of soft materials and span from material synthesis, processing, to design of
functional devices. He applies organic synthesis, polymer synthesis,
solution-based processing and nanofabrication in the discovery of new
polymers and multifunctional composites.
Our Soft Materials
Research Laboratory studies electronic polymers and nanostructured hybrid
materials. The research focuses on molecular synthesis and nano-scale
engineering for the development of new polymers and nano-structures with
desired electronic, photonic, and/or mechanical properties. The applications
of these materials are many folds, including flexible electronics,
artificial muscles, photovoltaics, wind energy generation, radiation
detection and protection, and biologically-inspired systems to name a few.
Current projects include:
actuators and generators:
These are based on dielectric elastomers exhibiting electrically-induced
strains as high as 400%. The polymer transducers have such advantages as
high energy and power densities, quietness, mechanical compliancy (for shock
resistance and impedance matching), high efficiency, lightweight, and low
cost. To improve the device performance and reliability, interpenetrating
polymer networks are being studied as a new generation of electroelastomers.
Fault tolerance is being introduced as a means to prolong operation
lifetime. The project involves mechanical design, fabrication, and testing
of polymer actuators and generators.
We started a new effort in achieving electronic devices that are flexible or
even stretchable. Carbon nanotubes are deposited into ultrathin coatings
with modest surface conductivity and semi-transparency. Using a stretchable
substrate and polymer semiconductors, flexible polymer LEDs and solar cells
can be fabricated. The holy-grail is to achieve devices wherein the active
area is stretchable.
Composites of inorganic compounds and conjugated polymers are prepared with
controlled nanostructures for photovoltaics or radiation detection. We
synthesized CdS nanorod arrays by electrochemical self-assembly, and CdS
thin coating by chemical bath deposition. High-Z nanoparticle polymer
composites are studied for gamma and x-ray scintillation.
The band gap, band edges (electron affinity and ionization potential),
optical absorption, photoluminescence color and quantum efficiency, and
carrier mobility can be modulated through the conjugated backbone or side
chains, structural regularity, molecular weight, purity, and molecular
ordering. We can thus tailor conjugated polymers for different applications
such as light emitting diodes, solar cells, thin film transistors, and
sensors. We fabricate smiconductor devices (LEDs, solar cells) using the
Selected Recent Publications:
“A Facile Route to Bulk High-Z Polymer Composites for Gamma Ray
Scintillation,” Y.S. Zhao, Z. Yu, A. Douraghy, A.F. Chatziioannou, Y. Mo,
Q. Pei, Chem. Commun., 6008–6010 (2008).
"Electrochemical Synthesis and Photovoltaic Property of Cadmium
Sulfide-Polybithiophene Interdigitated Nanohybrid Thin Films," D. Xi, H.
Zhang, B. Chen, S. Furst, Q. Pei, J. Phys. Chem. C, 112,
“Fault-Tolerant Dielectric Elastomers using Single-Wall Carbon
Nanotube Electrodes.” W. Yuan, L. Hu, Z. Yu, T. Lam, J. Biggs, S.M. Ha ,
D. Xi, B. Chen, M.K. Senesky, G. Grűner, Q. Pei, Advanced Materials
20, 621–625 (2008).
“Operating Mechanism of Light-emitting Electrochemical Cells,” Q.
Pei, A.J. Heeger, Nature Materials 7, 167 (2008).
“Nanoporous Carbon Nanotube Electrode for Stable Polypyrrole
Actuator”, Z. Yu, D. Xi, T. Lam, Q. Pei. Proc. SPIE, Vol. 6524,
“In-situ Preparation of Free-standing Nanoporous Alumina Template for
Polybithiophene Nanotube Arrays with a Concourse Base”, D. Xi, Q. Pei.
Nanotechnology, Vol. 18, 095602 (2007).
“Raman Studies of Optical Phonons in Vertical Cadmium Sulfide Nanorod
Arrays”, D. Xi, J. Li, Q. Pei, B. Chen. J. Mater. Res. Vol. 21,
“Effects of C70 Derivative in Low Bandgap Polymer Photovoltaic
Devices: Spectral Complementation and Morphology Optimization”, Y. Yao, C.
Shi, G. Li, V. Shrotriya, Q. Pei, and Y. Yang. Appl. Phys. Lett. Vol.
“Regioregular Copolymers of 3-Alkoxythiophene and Their Photovoltaic
Application”, C. Shi, Y. Yao, Y. Yang, Q. Pei. J. Am. Chem. Soc. Vol.
“Interpenetrating Polymer Networks for High-Performance
Electroelastomer Artificial Muscles”, S.M. Ha, W. Yuan, Q. Pei, R. Pelrine,
and S. Stanford. Advanced Materials Vol. 18, 887–891(2006).
Prospective graduate students and postdoctoral researchers with the
following specialties are welcome to apply: synthesis of conjugated
polymers; solution-based nanofabrication; polymer composites; polymer
processing; organic synthesis; thin film electronic devices; actuators and