• Ph.D., Physical Chemistry, University of Rochester, NY (1996)
• M.S., Physical Chemistry, University of Rochester, NY (1993)
• B.S., Chemistry, State University of New York at Geneseo (1991)

Areas of research:

• Chemical sensors
• All-optical sensor design
• Quantum dots
• Kelvin probe microanalysis
• Near field scanning optical microscopy

Research Web site: www.albany.edu/wwwres/sensors

Description of research:

Professor Carpenter's research engages in the integration of chemical sensors into system-on-a-chip technology platforms with the intent of enabling a cost effective and reliable solution for energy and environmental monitoring applications. A major research focus area for integrated chemical sensors is the development of materials with the required selectivity, specificity and reliability for the targeted sensing application. Carpenter's research group is utilizing a tailored design methodology using the unique properties of nanomaterials for the development of harsh environment compatible chemical sensors and also novel sensors for the sensitive and selective detection of hydrocarbons in groundwater, soil and ambient air monitoring applications.

Harsh Environment Chemical Sensors
Chemical sensors which are compatible with harsh environments (temperatures above 500°C in the presence of either oxidative or reductive atmospheres), are currently a barrier towards the development of control feedback and safety systems for combustion related applications that include: automotive, aerospace, gas turbines and solid oxide fuel cells. These sensing roadblocks are due to the degradation of the sensing system due to material incompatibilities and instabilities within the sensing environment. Carpenter's group is developing all-optical sensing techniques where the sensing component is exposed to the harsh environment and the optical characteristics of the material are interrogated remotely using standard optical techniques. The sensing elements are based on metal, bi-metallic, and metal-oxide nanoparticle doped metal-oxide nanocomposites. Currently, Carpenter's group has prototype materials that are able to reliably sense hydrogen for over 200 cycles at 650°C in an ambient air background carrier gas. Future work is aimed at developing a suite of tailored nanomaterials to sense methane, CO, NOx  and SOx.

All-Optical Hydrogen Sensor
The development of harsh environment compatible chemical sensors with sufficient reliability, sensitivity and selectivity requires the tailored design of the composition and  microstructure of the active sensing layer. Carpenter's research group has utilized this approach in the development of tailored chemical sensors for proton exchange membrane fuel cells. These efforts have led to the development of an intrinsically safe all-optical hydrogen sensor based on monitoring the optical properties of thin palladium alloy films. The tailored design process of the palladium alloy film including the alloying element and its composition will be detailed and correlated with the sensing properties. These tailor designed materials that were deposited in December 2002 continue to operate within 5% of their corresponding calibration curves and have response characteristics that are comparable or better than industrially available electronic based hydrogen sensors.

Semiconductor Quantum Dots: Hydrocarbon Sensors
Semiconductor nanocrystals (NCs) such as CdSe are ideal candidates for sensing applications due to their extremely high surface/volume ratio and sensitivity of their optical properties to the changes in their chemical environment. Carpenter's group focuses on exploring surface modification of CdSe nanocrystals by appropriate molecule anchoring. This approach will test the ability of donor-substituted aromatic ligands to form pi-complexes with electrophilic functionalities of molecules grafted to the surface of NCs by chemisorption or self-assembly. Due to their intrinsic sensitivity to their surrounding environment, modification of the surface environment of NCs significantly affects their photophysical and photochemical properties, which will be exploited for the development of sensing technologies. Experiments are underway to determine sensitivity of optical properties of the surface modified NCs toward the presence of various aromatic hydrocarbons.

Materials Characterization
Carpenter uses a wide range of analytical tools such as XRD, XPS, SEM-EDS, Auger spectroscopy, ellipsometry, Rutherford backscattering spectrometry, fluorescence, near field scanning optical microscopy, AFM, and SEPM to characterize, ex-situ, the material, optical and electrical properties of the tailored nanomaterials under development for sensor applications.

Chemical Sensor Test Stations
In-situ measurements of the sensing properties of the material under development at conditions that mimic the targeted environmental monitoring conditions are performed on several separate sensor test stations. Currently, Carpenter's group has two optical absorption sensor test stations that can operate up to 1000°C and up to 100°C with gas concentrations varied between ppb and % levels. A Kelvin probe sensor test station was installed in 2004 which will allow measurements of changes in work function as a function of changes in the operating temperature and the gas environment. Optical fluorescence based sensor test stations for single and up to 8 films was also installed in 2004.

Tailored Design
These measurements, while required to determine calibration tables outlining the sensitivity, reliability and response times of the sensor, are also used by Carpenter to determine the fundamental kinetics, thermodynamics and dynamics which provides a detailed understanding of the sensing mechanism. The sensing mechanism is then correlated with the material properties which through a material optimization process leads to the development of tailor-designed nanomaterials for chemical sensors.

Recent Publications:

G. Sirinakis, R. Siddique, P. H. Rogers, I. Manning, M. A. Carpenter
Development and Characterization of Au-YSZ Surface Plasmon Resonance Based Sensing Materials: High Temperature Detection of CO
Journal of Physical Chemistry B, 110, 13508 (2006)

Z. Zhao, M. A. Carpenter, D. Welch, H. Xia
All-Optical Hydrogen Sensor Based on a High Alloy Content Palladium Thin Film
Sensors and Actuators B, 113, 532 (2006)

George Sirinakis, Rezina Siddique, Kathleen A. Dunn, Harry Efstathiadis, Michael A. Carpenter, and Alain E. Kaloyeros
Spectro-ellipsometric Characterization of Au-Y₂O₃-stabilized ZrO₂ Nanocomposite Films
Journal of Materials Research, 20, 3320 (2005)

George Sirinakis, Rezina Siddique, Christos Monokroussos, Michael A. Carpenter, and Alain E. Kaloyeros
Microstructure and optical properties of Y₂O₃-stabilized ZrO₂-Au nanocomposite films
Journal of Materials Research, 20, 2516 (2005)

Z. Zhao, M. A. Carpenter
Annealing Enhanced Hydrogen Absorption in Nanocrystalline Pd/Au Sensing Films
Journal of Applied Physics, 97, 124301 (2005)

Z. Zhao, Y. Sevryugina, M. A. Carpenter, D. Welch, H. Xia
All-Optical Hydrogen Sensing Materials Based on Tailored Palladium Alloy Thin Films
Analytical Chemistry, 76, 6321 (2004)

M. A. Carpenter, E. Lifshin, R. Gauvin
SEM-EDS Quantitative Analysis of Aerosols = 80nm: Impacts on Atmospheric Aerosol Characterization Campaigns
Microscopy and Microanalysis 8 (Suppl. 2) (2002)

Patents:

Carpenter, Michael A.; Sirinakis, George
Optical methods and systems for detecting a constituent in a gas containing oxygen in harsh environments
PCT/US2007/64665, (2007).

Zhouying Zhao, Michael A. Carpenter
Methods for Forming Palladium Alloy Thin Films and Optical Hydrogen Sensors Employing Palladium Alloy Thin Films
Serial Number: 11/049,833, Filed: February 3, 2005