APPLICATIONS OF TECHNOLOGY:
- Solar Cells
- Semiconductor emitters and detectors
- Quantum yield enhancement to near-unit values
- Surface recombination velocity reduction
- Improved Voc in solar cells
- PL peak intensity increase
Berkeley Lab researchers led by Ali Javey used chemical treatments utilizing an organic super acid molecule to passivate and / or repair surface defects in semiconductor systems. Surface defects dominate the behavior of minority carriers in semiconductors and optoelectronic devices. Photoluminescence quantum yield (QY), which dictates efficiency of optoelectrics such as LEDs, lasers, and solar cells, is extremely low in materials with a large number of surface defects.
The team developed a bis(trifluoromethane) sulfonamide (TFSI) solution for passivation/repair of surface defects in 2D transition metal dichalcogenide (TMDC). This air-stable solution-based chemical treatment provides unmatched photoluminescence QY enhancement to values near 100% without changing the surface morphology. The treatment eliminates defect-mediated non-radiative recombination, which eliminates the low performance limit of TMDC and enhances its minority carrier lifetime.
This novel development can address surface passivation in numerous semiconductors which will lead to highly efficient light emitting diodes, lasers and solar cells based on 2D materials.
FOR MORE INFORMATION:
M. Amani, D.-H. Lien, D. Kiriya, J. Xiao, A. Azcatl, J. Noh, S. R. Madhvapathy, R. Addou, S. K. C., M. Dubey, K. Cho, R. M. Wallace, S.-C. Lee, J.-H. He, J. W. Ager III, X. Zhang, E. Yablonovitch, A. Javey, “Near-Unity Photoluminescence Quantum Yield in MoS2”, Science, 350, 1065-1068, 2015.
M. Amani, P. Taheri, R. Addou, G. H. Ahn, D. Kiriya, D.-H. Lien, J. W. Ager III, R. M. Wallace, A. Javey. “Recombination kinetics and effects of superacid treatment in sulfur and selenium based transition metal dichalcogenides”, Nano Letters, DOI: 10.1021/acs.nanolett.6b00536.
DEVELOPMENT STAGE: Proven principle. MoS2, the prototypical 2D material, had an increase in QY from 0.6% to values greater than 95%. Its longest recorded lifetime was 10.8 +/- 0.6 nanoseconds, and the PL peak intensity had a 190-fold increase in intensity post-treatment.
STATUS: Issued U. S. Patent #9,852,927. Available for licensing or collaborative research.
REFERENCE NUMBER: 2015-159
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