Electroluminescent, Polycrystalline, Cadmium Selenide Nanowire Arrays

Talin Ayvazian, Wytze E. van der Veer, Wendong Xing, Wenbo Yan, and Reginald M. Penner*
ACS Nano, 7 (2013) 9469.


Polycrystalline CdSe nanowires prepared by LPEN emit light when current flows through them. This process, called electroluminescence (or EL), is as efficient in these polycrystalline nanowires as it is in single crystalline CdSe nanowires studied previously - completely amazing. EL emission occurs at the 1.74 eV bandgap of the CdSe, and its intensity increases super-linearly with applied voltage.

Water Oxidation Using a Cobalt Monolayer Prepared by Underpotential Deposition

David A. Marsh , Wenbo Yan , Yu Liu , John C. Hemminger , Reginald M. Penner*, and A.S. Borovik*
Langmuir, 29 (2013) 14728.


One problem with the measurement of the catalytic activity of an electrocatalyst is the accurate determination of the AMOUNT of the catalyst on the electrode. In this work, Dave and Wenbo find that a highly active water oxidation catalyst can be prepared by electrodepositing a single atomic layer of cobalt onto a gold electrode surface. Their work also provides information on the chemical state of this cobalt under reaction conditions.

Laser Annealing of Nanocrystalline Gold Nanowires

Jungyun Kim, Chia-Yu Lin, Wendong Xing, Martha L. Mecartney, Eric O. Potma, and Reginald M. Penner*
ACS Appl. Mater. Interfaces 5 (2013) 6808.


Grain growth can be induced in gold nanowires using laser heating. This process is spatially selective, and fast. During laser annealing, the 4-contact electrical resistance of the nanowire is reduced by 30 - 65%. These resistance decreases are associated with an increase in the mean grain diameter within these nanowires, measured using transmission electron microscopy, of up to 300%.

Sub-nanomolar Detection of Prostate Specific Membrane Antigen in Synthetic Urine

Kritika Mohan, Keith C. Donavan, Jessica A. Arter, Reginald M. Penner*, and Gregory A. Weiss*
J. Am. Chem. Soc. 135 (2013) 7761.


The sensitive detection of cancer biomarkers in urine could revolutionize cancer diagnosis and treatment. Such detectors must be inexpensive, easy to interpret, and sensitive. This report describes a bioaffinity matrix of viruses integrated into PEDOT films for electrochemical sensing of prostate-specific membrane antigen (PSMA), a prostate cancer biomarker. High sensitivity to PSMA resulted from synergistic action by two different ligands to PSMA on the same phage particle.

Electrodeposited Light-Emitting Nanojunctions

Wendong Xing, Wenbo Yan, Talin Ayvazian, Yong Wang, Eric Potma, and Reginald M. Penner*
Chemistry of Materials 25 (2013) 623.


The use of prefabricated gold nanogaps provides an expedient way to study light emission from electrodeposited CdSe, Wendong discovered. Light is emitted from these junctions at energies close to the bandgap of CdSe - a first - but the quantum yield for emission is just 10-6. The challenge will be to uncover how this emission process can be made more efficient.

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