Behrang Hamadani (Fed)

Dr. Behrang H. Hamadani is a Project Leader in the Heat Transfer and Alternative Energy Systems (HTAES) Group of the Engineering Laboratory (EL) at the National Institute of Standards and Technology (NIST). Behrang joined the HTAES Group in November of 2010 following his postdoctoral work at the Center for Nanoscale Science and Technology at NIST. His graduate research work was focused on studying the physics of electronic charge transport and injection in organic thin film devices and his postdoctoral work was on charge transport in organic electronic devices and also on photoconductive scanning probe microscopy of thin film solar cells. He currently leads a project centered on electronic and electro-optical measurements and characterization of photovoltaic materials, solar cells and modules. To this end, certain key electrical output and optical parameters must be accurately evaluated. These include external quantum efficiency measurements of solar cells, the external luminescence yield measurements, spectral irradiance measurements of the incident light, linearity of device response with light intensity, angular effects, solar simulator characteristics etc. The ultimate objective of this research is to accurately predict device performance under standard reporting conditions and also understand the photovoltaic losses that hinder achievement of high efficiency cells and a reliable performance either in the field or under other special illumination conditions. Behrang also leads smaller research projects focused on special related topics and more advanced measurement areas, including spectral-dependent charge carrier lifetime measurements utilizing the non-contact photoconductance sensing methods, modulated photocurrent spectroscopy for studying charge carrier recombination phenomena, electroluminescence and photoluminescence measurements, and voltage and light bias dependent spectral response measurements on multi-junction solar cells.

Dr. Hamadani received a B.S. in physics from University of Texas at Dallas (summa cum laude) in 2001, and a Ph.D. also in physics from Rice University (2007) under the guidance of Prof. Douglas Natelson. His dissertation work was titled, “Electronic Charge Injection and Transport in Organic Field-Effect Transistors”. Behrang has published over 45 journal articles, 2 book chapters, 2 patents and has given over 40 invited and contributed presentations on his research at national and international conferences, universities and industrial research labs. He is currently a member of the American Physical Society, and the ASTM International and regularly participates in Standards committee meetings, proposal review panels and advisory boards. He also occasionally teaches fundamental physics courses to college students.

Current Programs/Projects:

• Reference solar cell calibrations based on the absolute irradiance spectral responsivity method
• Nonlinearity of PV photocurrent response with irradiance
• Optical and electro-optical measurements of multi-junction solar cells
• Hyperspectral imaging techniques for solar cell measurements
• Photovoltaic measurements under low irradiance conditions
• Charge carrier lifetimes in silicon using an LED-based photoconductance sensing method

Facilities:

NIST PV Characterization Laboratory

2015 Engineering Laboratory Mentoring Award

Presidential Early Career Award for Scientists and Engineers (PECASE), 2019