Publications

Dec, 2013

Journal

Bilayer self-assembly on a hydrophilic, deterministically nano-patterned surface

We present measurements of the in-situ, microscopic architecture of a self-assembled bilayer at the interface between a regularly nano-patterned surface and an aqueous sub-phase using neutron reflectometry. The substrate is patterned with a rectangular array of nano-scaled holes. Because of the high quality of the pattern, using neutron reflectometry, we are able to map th…

Nov, 2013

Journal

Morphological origin for the stratification of P3HT:PCBM blend film studied by neutron reflectometry

Understanding the origin for the film stratification of electron donor/acceptor blend is crucial for high efficiency organic photovoltaic cell. In this study, P3HT:PCBM blend is deposited onto hydrophilic and hydrophobic substrate to examine the film stratifications. The neutron reflectivity results show that, on the different surfaces, PCBM diffuses toward the two interfa…

Sep, 2013

Journal

High-Performance Organic Field-Effect Transistors with Dielectric and Active Layers Printed Sequentially by Ultrasonic Spraying

High-performance, flexible organic field-effect transistors (OFETs) are reported with PVP dielectric and TIPS-PEN active layers sequentially deposited by ultrasonic spray-coating on plastic substrate. OFETs fabricated in ambient air with a bottom-gate/top-contact geometry are shown to achieve on/off ratios of >104 and mobilities as high as 0.35 cm2/Vs. These rival the char…

Jun, 2013

Journal

Germanium as negative electrode material for sodium-ion batteries

Germanium electrodes show a reversible Na-ion reaction at potentials of 0.15 and 0.6 V during discharge and charge, respectively. The reaction is accompanied with a reversible capacity close to 350 mAh g-1, which matches the value expected for the formation of NaGe. The electrode capacity retention is stable over 15 cycles but declines somewhat rapidly afterwards. This dec…

Mar, 2013

Journal

Surface-Induced Orientation Control of CuPc Molecules for the Epitaxial Growth of Highly Ordered Organic Crystals on Graphene

The epitaxial growth and preferred molecular orientation of copper phthalocyanine (CuPc) molecules on graphene has been systematically investigated and compared with growth on Si substrates, demonstrating the role of surface-mediated interactions in determining molecular orientation. X-ray scattering and diffraction, scanning tunneling microscopy, scanning electron microsc…

Jan, 2013

Journal

Solvent Quality-Induced Nucleation and Growth of Parallelepiped Nanorods in Dilute Poly(3-Hexylthiophene) (P3HT) Solution and the Impact on the Crystalline Morphology of Solution-Cast Thin Film

Dec, 2011

Journal

P3HT-b-PS Copolymers as P3HT/PCBM Interfacial Compatibilizers for High Efficiency Photovoltaics

To control the donor-acceptor phase separation for more efficient organic bulk heterojunction photovoltaic cells, poly(3-hexylthiophene)-block-polystyrene (P3HT-b-PS) diblock copolymer was added to serve as a compatibilizer in a P3HT/ [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PCBM) blend. An addition of 5 wt% of P3HT-b-PS copolymer in the P3HT/PCBM b…