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June 2013

Probing carrier dynamics below the surface of solar cells

Scientific Achievement

Optically probed the charge carrier lifetime below the surface of solar materials using two-photon (2P) time-resolved PL mapping, and demonstrated that the traditional one-photon (1P) technique can underestimate the bulk lifetime in CdTe by 10x.

Significance and Impact

Improving carrier lifetime is a critical component in boosting solar cell efficiencies, but accurately measuring the bulk carrier lifetime is one of the greatest challenges in evaluating solar materials. 2P tomography can non-destructively map bulk lifetime, surface recombination and other properties within photovoltaic materials to locate areas of reduced device performance.

Research Details

E. S. Barnard, E. T. Hoke, S. T. Connor, J. R. Groves, T. Kuykendall, Z. Yan, E. C. Samulon, E. D. Bourret-Courchesne, S. Aloni, P. J. Schuck, C. H. Peters & B. E. Hardin. Scientific Reports 2013 3, 2098.