Penner Group, all dressed up for the E.K.C. Lee Dinner, May 21 2015.

Catalytically Activated Palladium@Platinum Nanowires for Accelerated Hydrogen Gas Detection

Xiaowei Li, Yu Liu, John C. Hemminger, and Reginald M. Penner*
ACS Nano, 9 (2015) 3215.

The response/recovery speed of nanoscale chemical sensors is prone to retardation by rate-limiting surfacechemical kinetics because as the critical dimension of the sensor is reduced, the diffusional flux of molecules to sensor surfaces is increased. The performance of nanoscale sensors should therefore be hypersensitive to catalysts. Here Xiaowei has demonstrated that H2 response and recovery kinetics for a highly optimized H2 sensor consisting of a Joule-heated Pd nanowire can be significantly accelerated by the addition of minute quantities (e.g., 1 ML) of a Pt metal catalyst to the nanowire surface..

Gold Nanowire Thermophones

Rajen Dutta, Brian Albee, Wytze E. van der Veer, Keith C. Donovan, Dimitri Papamoschou, Reginald M. Penner*
J. Phys. Chem. C, 118 (2014) 29101.

Ultra-long (mm scale) polycrystalline gold nanowires can function as loud speakers. Raj fabricated arrays of 4000 linear gold nanowires at 5 micron pitch on glass surfaces using lithographically patterned nanowire electrodeposition (LPNE). Then he evaluated the properties of these nanowire arrays for generating sound as a function of frequency (from 5 - 120 kHz), angle from the plane of the nanowires, input power (from 0.30 - 2.5 W) and the width of the nanowires in the array (from 270 to 500 nm.)

Electrodeposited Nanophotonics

Reginald M. Penner*
J. Phys. Chem. C, 118 (2014) 17179.

We review the use of electrodeposited, polycrystalline (pc), cadmium selenide (CdSe) in nanowires and nanogap device structures for photonics. The photodetectors and photon emitters we describe are symmetrical metal-semiconductor-metal (M-S-M) devices prepared either by the evaporation of two gold contacts onto linear arrays of pc-CdSe nanowires prepared using lithographically patterned nanowires electrodeposition (LPNE), or by the electrodeposition of pc-CdSe directly onto gold nanogaps.

A Lithographically Patterned Capacitor With Horizontal Nanowires of Length 2.5 mm Wenbo Yan, Mya Le Thai, Rajen Dutta, Xiaowei Li, Wendong Xing, and Reginald M. Penner*
ACS App. Mat. Interf., 6 (2014) 5018.

Wenbo prepared a symmetrical hybrid capacitor consisting of interdigitated, horizontal nanowires. Each of the 750 nanowires within the capacitor is 2.5 mm in lengt - yes that's right - 1 cm! Each nanowire consisted of a gold nanowire core (40 x 200 nm) encapsulated within a hemicylindrical shell of delta-phase MnO2 (thickness = 60--220 nm). Wenbo patterned these Au@MnO2 nanowires on a planar glass surface using lithographically patterned nanowire electrodeposition (LPNE). She measured a power density of 165 kW/kg and an energy density of 24 Wh/kg for a nanowire array in which the MnO2 shell thickness was 68 nm.

Reduction of Spectral Interferences Using Ultraclean Gold Nanowire Array in the LDI-MS Analysis of Peptides L. Colaianni; S.C. Kung, D.K. Taggart; R.A. Picca, J. Greaves, R.M. Penner, and N. Cioffi*
Analytical and Bioanalytical Chemistry, 406 (2014) 4571.

Lorenzo and Nicola assessed the utility of gold nanowire arrays (AuNWAs) as anchors in the matrix-free laser desorption ionization mass spectrometry (LDI-MS) analysis of the low molecular weight peptide leucine enkephalin. Then, Lorenzo subjected these AuNWAs to a series of cleaning procedures. Iinterference-free, intense, mass spectrometra were obtained for leucine enkephalin characterized by limits of detection as low as 0.5 and 2.5 pmol for the positive and negative analysis modes, respectively.

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