Blue Light Emitting Defective Nanocrystals Composed of Earth-Abundant Elements
Eric Hansen a, Yun Liu a, Hendrik Utzat a, Sophie Bertram a, Jeffrey Grossman a, Moungi Bawendi a
a Massachusetts Institute of Technology - USA, Cambridge, United States
nanoGe Fall Meeting
Proceedings of nanoGe Fall Meeting19 (NGFM19)
#NCFun19. Fundamental Processes in Semiconductor Nanocrystals
Berlin, Germany, 2019 November 3rd - 8th
Organizers: Ivan Infante and Jonathan Owen
Poster, Eric Hansen, 341
Publication date: 16th July 2019

Ternary (I-III-IV) nanocrystals (NCs) have been widely reported to contain optically-active defect states in the case of Cu-In-S compositions, which result in large Stokes shift and long photoluminescence (PL) lifetimes (~200 ns). However, there are minimal reports of In-free composition that exhibit efficient photoluminescence (PL). Here, we report a novel solution-phase synthesis of ~4 nm defective nanocrystals (DNCs) composed of Copper, Aluminum, Zinc, and Sulfur with ~20% quantum yield and an attractive PL maximum of 450 nm. Extensive spectroscopic characterization suggests the presence of highly-localized electronic states due to measurement of fast PL lifetimes (~1 ns), large vibrational energy spacing, and temperature-independent PL linewidth and PL lifetime (between room temperature and ~5K). Furthermore, computational calculations were performed to suggest that the observed optical properties arise from bound exciton transitions associated with Al3+ substitutional defects within a CuAl5S8 crystal lattice. The results reported here provide an important analog to previously-explored In-based ternary nanocrystals that exhibit unique optoelectronic characteristics.

This work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. 1541959. CNS is part of Harvard University.

© Fundació Scito
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