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Published May 5, 2022 | Published + Supplemental Material
Journal Article Open

Role of Atomic Structure on Exciton Dynamics and Photoluminescence in NIR Emissive InAs/InP/ZnSe Quantum Dots


The development of bright, near-infrared-emissive quantum dots (QDs) is a necessary requirement for the realization of important new classes of technology. Specifically, there exist significant needs for brighter, heavy metal-free, near-infrared (NIR) QDs for applications with high radiative efficiency that span diverse applications, including down-conversion emitters for high-performance luminescent solar concentrators. We use a combination of theoretical and experimental approaches to synthesize bright, NIR luminescent InAs/InP/ZnSe QDs and elucidate fundamental material attributes that remain obstacles for development of near-unity NIR QD luminophores. First, using Monte Carlo ray tracing, we identify the atomic and electronic structural attributes of InAs core/shell, NIR emitters, whose luminescence properties can be tailored by synthetic design to match most beneficially those of high-performance, single-band-gap photovoltaic devices based on important semiconductor materials, such Si or GaAs. Second, we synthesize InAs/InP/ZnSe QDs based on the optical attributes found to maximize LSC performance and develop methods to improve the emissive qualities of NIR emitters with large, tunable Stokes ratios, narrow emission linewidths, and high luminescence quantum yields (here reaching 60 ± 2%). Third, we employ atomistic electronic structure calculations to explore charge carrier behavior at the nanoscale affected by interfacial atomic structures and find that significant exciton occupation of the InP shell occurs in most cases despite the InAs/InP type I bulk band alignment. Furthermore, the density of the valence band maximum state extends anisotropically through the (111) crystal planes to the terminal InP surfaces/interfaces, indicating that surface defects, such as unpassivated phosphorus dangling bonds, located on the (111) facets play an outsized role in disrupting the valence band maximum and quenching photoluminescence.

Additional Information

© 2022 The Authors. Published by American Chemical Society - Attribution 4.0 International (CC BY 4.0). Received 2 March 2022. Revised 21 March 2022. Published online 26 April 2022. Published in issue 5 May 2022. This work (material synthesis, modeling, and characterization) has been primarily supported by the Photonics at Thermodynamic Limits Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences under Award Number DE-SC0019140. Synthesis and characterization of materials was carried out in part in the Illinois Materials Research Laboratory Central Research Facilities, University of Illinois. The authors would like to thank Julio Soares for assistance with time-resolved photoluminescence measurements and analysis and Danielle Gray for fruitful discussions on sample digestion for ICP–OES. D.J. acknowledges the support of the Computational Science Graduate Fellowship from the U.S. Department of Energy under Grant No. DE-SC0019323. Author Contributions. Conceptualization: M.J.E., D.J., D.R.N., M.E.P., M.M.P., H.A.A., E.R., and R.G.N; methodology: M.J.E., D.J., D.R.N., and D.W; investigation: M.J.E., D.J., M.M.H., D.R.N., D.W., B.E.M., H.-W.H., and M.K.; resources: H.A.A., E.R., and R.G.N; writing: M.J.E. and D.J.; review and editing: M.E.P., H.A., M.M.P., and J.W; supervision: M.J.E., J.-M.Z., H.A.A., E.R., and R.G.N.; and funding acquisition: H.A.A., E.R., and R.G.N. The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. The authors declare no competing financial interest.

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Published - acs.jpcc.2c01499.pdf

Supplemental Material - jp2c01499_si_001.pdf


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August 22, 2023
October 24, 2023