Time-Resolved and Temperature-Dependent Fractional Amplitude Contributions to the Broadband Emission of CdSe Quantum Dots
Abstract
The broadband spontaneous emission of excitons in CdSe quantum dots (QDs) is of great interest for the spectral imaging of living organisms or specific substances in the visible spectral region as well as in the biological optical window near the infrared spectral region. Semiconductor QDs that are near the bulk Bohr radius exhibit wide spectral tunability and high color purity due to quantum confinement of excitons within the dot boundary. However, with reducing dot size, the role of the surface-trapped state increases. The temperature-dependent photoluminescence (PL) confirms this with a ~3:1 emission intensity decrease from the surface-trapped state compared to the band edge. Large crystal irregularity, dangling ions, and foreign molecules can introduce new electronic transitions from surface-trapped states that provide broad spontaneous emission in the spectral region from visible to near IR in addition to the band edge emission. The time-resolved PL analyzed the fractional contributions of band edge, surface-trapped states, and possible intermediate trapped states to the broad spectral emission in order to characterize the CdSe QDs.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 22, 2021
- Source ID
- 10.3390/cryst11111284
Entities
People
- Bagher Tabibi
- Ignacy Gryczynski
- Jaetae Seo
- Kyle Burney
- Quinton Rice
- Sangram Raut
- William Yu
- Zygmunt Gryczynski
Organizations
- Army Research Office
- Hampton University
- Louisiana State University
- National Aeronautics and Space Administration
- National Institutes of Health
- National Science Foundation
- Texas Christian University
- University of North Carolina at Pembroke
- University of North Texas Health Science Center