February 4th, 2013

Title: Role of Surfaces and Their Analysis in Photovoltaics, Robert L. Opila, Ph.D.
University of Delaware
Department of Materials Science and Engineering
3– 4 P.M.
Room A113 – CBE Seminar Room

Number of Attendees: 25
Number of IEEE Member Attendees: 3
Number of Non-Member Attendees: 22
Description:
Surface chemistry is intrinsically related to the performance of solar cells. In solar cells the generation and collection of charge carriers determines their efficiency. Effective transport of charge carriers across interfaces and minimization of their recombination at surfaces and interfaces is of utmost importance. Thus, the chemistry at the surfaces and interfaces of these devices must be determined, and related to their performance. In this talk we will discuss the role of two important interfaces. First, the role of surface passivation is very important in limiting the rate of carrier of recombination. We have been studying organic passivants on H-terminated Si surfaces, and establishing extremely low surface recombination rates. Here we are combining spectroscopic measurements of the surface of a Si device with electrical measurements to ascertain what factors determine the quality of a solar cell passivation. In addition, the quality of the heterojunction interface in a ZnSe/CdTe solar cell affects the output voltage of this device. X-ray photoelectron spectroscopy gives some insight into the composition of the interface, while ultraviolet photoemission yields the relative energy of the two materials’ valence bands at the junction, which controls the open circuit voltage of the solar cell. The relative energies of ZnSe and CdTe at the interface are directly affected by the material quality of the interface through processing.

February 15, 2013

Title: Li-air Batteries and Li-air Flow Batteries Presentation, Dr. Jim Zheng
Attendance:
Number of Attendees: 20
11 A.M.
Room A113, FAMU-FSU College of  Engineering
2525 Pottsdamer Street, Tallahassee, FL

Description:
Recently, the Li-air batteries have been attracted much attention because of possible of extremely high energy density. The theoretical energy density of the batteries can be over 3,000 Wh/kg which is more than 10 times greater than that of Li-ion batteries.

However, the practical energy density of Li-air batteries is much less than the theoretical predication. Furthermore, it was found that the energy density of Li-air batteries is mainly limited by the specific capacity of air cathode electrode which made with porous carbon. The specific capacity of the air electrode is dependent on many factors, particularly, the thickness of the electrode and the discharge current density. In addition to the energy density, Li-air batteries also suffered from other major deficiencies including extremely low power (or current), density and poor cyclability, and sensitivity to the moisture.

October 17, 2013

Title: Tour of the Hopkins Power Generation Plant
Description: A technical tour of the Hopkins Power Plant was conducted for IEEE members and other guests.

The IEEE Tallahassee Area Section has arranged for IEEE members and guests to take a tour of the  Arvah B. Hopkins Power Plant on Thursday, October 17th at 2:30 PM.

The  Arvah B. Hopkins Power Generating Station (http://www.talgov.com/you/you-learn-utilities-electric-hopkins.aspx) is a 504 MW power generation plant using primarily natural gas for fuel.  It is
located three miles west of Capital Circle SW on Geddie Road, between highways 20 and 90.

Guest Attendance 2
IEEE Member Attendance 11
Start Time 2013-10-17 14:30:00
End Time 2013-10-17 17:00:00
Time Zone America/New_York
Location
Region 3
Section TALLAHASSEE AREA
Organizational Unit PE31
City Tallahassee
State/Province Florida
Country United States

 

November 20, 2013

Title: IEEE MagLab Power Tour
Description:
IEEE “back lot” tour of the power system in the National High Magnetic Field Laboratory

A behind the scenes tour of the FSU’s National High Magnetic Field Laboratory.

This tour explains the power systems used to supply the magnets in the labs given by the Facility Management Engineer, John Kynoch.  After this tour you may actually believe the lab has the “power” to control the
weather.

LOCATION: National High Magnetic Field Lobby, 1800 E. Paul Dirac Drive, Tallahassee, FL
IEEE Member Attendance 16
Start Time 2013-11-20 17:30:00
End Time 2013-11-20 19:30:00
Time Zone America/New_York
Location
Region 3
Section TALLAHASSEE AREA
Organizational Unit PE31
City Tallahassee
State/Province Florida
Country United States