Related Experiment Video
Updated: Sep 14, 2025
12:57
Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection
Published on: October 13, 2017
9.3K
Stimulated Emission from Below the Bandgap in Giant Quantum Shells
Amelia D Waters1,2, Mykhailo V Bondarchuk1,3, Christopher M Hicks1,3
1The Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States.
Journal of the American Chemical Society
|July 24, 2025
Summary
Giant colloidal quantum shells overcome limitations in semiconductor nanocrystals for optical gain media. This breakthrough enables broader spectral ranges and longer lifetimes, paving the way for advanced light sources.
Area of Science:
- Materials Science
- Nanoscience
- Optoelectronics
Background:
- Colloidal semiconductor nanocrystals (NCs) are promising for solution-processable optical gain media.
- Nonradiative Auger recombination in NCs limits optical gain lifetime and spectral range.
Purpose of the Study:
- To overcome limitations of NCs in optical gain media by suppressing Auger recombination.
- To achieve broad spectral gain, including sub-bandgap energies, using novel NC architectures.
Main Methods:
- Fabrication of giant colloidal quantum shells (g-QSs) with a CdSe shell on a CdS core.
- Ultrafast transient absorption and photoluminescence spectroscopy to analyze optical gain.
Main Results:
- g-QSs architecture minimizes exciton-exciton interactions, suppressing Auger recombination.
- Achieved one of the broadest optical gain bandwidths for colloidal nanomaterials.
- Demonstrated unusual sub-bandgap gain via Auger-assisted radiative recombination.
Conclusions:
- Giant colloidal quantum shells offer a unique gain regime in bulk-nanocrystal hybrid systems.
- This approach overcomes key limitations for NC-based optical gain media.
- Presents a promising pathway for developing solution-processable light sources.
Related Concept Videos
01:01Energy Bands in Solids
1.3K
Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels.
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
1.3K
01:23Photoluminescence: Fluorescence and Phosphorescence
2.3K
Photoluminescence is a process where a molecule absorbs light energy and re-emits it in the form of light. This phenomenon occurs when a substance absorbs photons, promoting its electrons to higher energy level excited states, followed by a relaxation process in which the electrons return to their original ground state energy levels and emit light. Photoluminescence is widely observed in various materials, including semiconductors, and organic and inorganic compounds.
A pair of electrons in a...
A pair of electrons in a...
2.3K
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
1.8K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
1.8K
01:14Molecular Spectroscopy: Absorption and Emission
3.4K
Molecules possess discrete energy levels called quantum states. Unlike atoms, which have simpler energy levels, molecules possess additional rotational and vibrational energy levels. Each energy level is separated by an energy gap, with the gaps between adjacent electronic, vibrational, and rotational levels varying significantly. The three types of energy levels in a diatomic molecule are shown in Figure 1.
3.4K
02:39Emission Spectra
65.3K
When solids, liquids, or condensed gases are heated sufficiently, they radiate some of the excess energy as light. Photons produced in this manner have a range of energies, and thereby produce a continuous spectrum in which an unbroken series of wavelengths is present.
65.3K
01:25Deactivation Processes: Jablonski Diagram
891
Luminescence, the emission of light by a substance that has absorbed energy, is a process that involves the interaction of molecules with light. The energy-level diagram, or Jablonski diagram, is a graphical representation of these interactions, illustrating the various states and transitions a molecule can undergo. In a typical Jablonski diagram, the lowest horizontal line represents the ground-state energy of the molecule, which is usually a singlet state. This state represents the energies...
891