Dr. Pauls Stradins is the principal scientist and a project leader of the Si PV in the Energy Sciences directorate at NREL. The project core lies within the High-Efficiency Crystalline Materials Photovoltaics group. In addition, it involves theory, analytical microscopy, and atomic layer deposition scientists. Stradins received his master of science degree from the Moscow Institute of Physics and Technology, his Ph.D. from the Latvian Institute of Physics, then spent five years in Professor Fritzche's group at the University of Chicago followed by another five years in the Thin-Film Si Solar Cells Superlab of AIST Tsukuba, Japan before joining NREL in 2002. His work has encompassed Si in applications to PV and beyond (such as electric memories and patented thin-film neutron detector). He has contributed to understanding amorphous Si (e.g., Staebler-Wronski effect at cryogenic temperatures), crystalline film Si for PV (e.g., epitaxial growth mechanisms by hot-wire CVD and solid-phase crystallization), nanoparticle Si (its potential for PV by both experiment and theory, attachment and role of surface ligands), and optical properties of black Si.

For the past two years, Stradins has led the effort to build a new Si program at NREL, focusing on:

• Passivated contacts science for industrially relevant, highly efficient single-junction wafer Si cells
• Tandem structures with Si bottom cell leading to cell/module efficiencies beyond the single-junction Si limit.

Stradins has published more than 55 papers, holds five patents, and won an R&D 100 award. He is a member of REMSEC at the Colorado School of Mines, holds a research professor appointment, and teaches a nanoscale physics and technology graduate course. He is also an organizer of the Symposium A (Emerging Si Science and Technology) of the MRS and a Foreign Member of the Latvian Academy of Sciences. Stradins leads the NREL effort in several DOE-funded, Si-related collaborative projects with Georgia Institute of Technology, Colorado School of Mines, and Fraunhofer Institute.

Patents

U.S. 8,239,165; 7,601,215; 8,389,422; 8,466,447; 8,569,708

Featured Work

Lee, B. G.; Hiller, D.; Luo, J. W.; Semonin, O. E.; Beard, M. C.; M.Zacharias, M.; Stradins, P. "Strained Interface Defects in Silicon Nanocrystals,"Adv. Funct. Mater. 22, 3223–3232 (2012), http://dx.doi.org/10.1002/adfm.201200572

Anderson, I. E.; Shircliff, R. A.; Macauley, C.; Smith, D. K.; Lee, B. G.; Agarwal, S.; Stradins, P.; and Collins, R. T. "Silanization of Low-Temperature-Plasma Synthesized Silicon Quantum Dots for Production of a Tunable, Stable, Colloidal Solution." The Journal of Physical Chemistry C, 2012 vol. 116 (6) pp. 3979-3987. http://dx.doi.org/10.1021/jp211569a

Luo, J. W.; Stradins, P.; Zunger, A.; "Matrix-Embedded Silicon Quantum Dots for Photovoltaic Applications: A Theoretical Study of Critical Factors," Energy and Environmental Science 4, 2546-2557 (2011), http://dx.doi.org/10.1039/C1EE01026C

Jariwala, B. N.; Kramer, N. J.; Petcu, M. C.; Bobela, D. C.; van de Sanden, M. C. M.; Stradins, P.; Ciobanu, C. V.; Agarwal, S. "Surface Hydride Composition of Plasma-Synthesized Si Nanoparticles," Journal of Physical Chemistry C115, 20375–20379 (2011), http://dx.doi.org/10.1021/jp2028005

Branz, H. M.; Yost, V. E.; Ward, S.; Jones, K. M.; To, B.; Stradins, P."Nanostructured Black Silicon and the Optical Reflectance of Graded-Density Surfaces,"Appl . Phys. Lett. 94, 231121 (2009), http://dx.doi.org/10.1063/1.3152244

Martin, I. T.; Teplin, C. W.; Branz, H. M.; Stradins, P. "Physics and Chemistry of Hot-Wire Chemical Vapor Deposition from Silane: Measuring and Modeling the Silicon Epitaxy Deposition Rate," J. Applied Physics 107 54906 (2010), http://dx.doi.org/10.1063/1.3298455