Summary:
Researchers in UCLA’s Department of Chemistry and Biochemistry have developed an innovative synthesis technique to create ultrasmall Mercury Telluride (HgTe) quantum dots, offering tunable optoelectronic properties and high photoluminescent quantum yields across the infrared spectrum.
Background:
HgTe quantum dots are gaining popularity for research and integration into infrared and light-emitting technologies due to their unique ability to exhibit narrow energy transitions across the entire infrared spectrum. Additionally, HgTe quantum dots offer exceptional band gap tunability, making them promising candidates for low-cost infrared photodetection alternatives. However, significant challenges remain in this field, including instability in process development and nonuniform synthesis, which can hinder scalability. Furthermore, there has been little research exploration of the ultrasmall scale of HgTe quantum dots within the near-infrared spectral window. Thus, there is a need for uniform synthesis methods of HgTe quantum dots that yield consistent particles with high photoluminescent quantum yield, enabling broad applications across all infrared wavelength technologies.
Innovation:
Professor Justin Caram and his research team have developed an innovative technique for synthesizing ultrasmall, colloidally stable HgTe quantum dots with near-unity performance in the near-infrared (NIR) range. These quantum dots exhibit remarkable photoluminescence quantum yields of up to 95%, outperforming current research yields by 20-45%. Additionally, the team’s sample retained this high yield in the solid state, enabling the first-ever photoluminescence imaging and blinking studies of HgTe quantum dots. In other experiments, the quantum dots demonstrated exceptional photostability, maintaining photostability for over six minutes under 405 nm excitation. Ultimately, the HgTe quantum dots produced feature tunable size, reaction time, and optical properties, alongside outstanding photostability and photoluminescence quantum yield across a wide infrared spectrum.
Potential Applications:
● Imaging systems
● Light-emitting devices
● Short-wave infrared cameras
● Photodetection
● Infrared fluorophores
Advantages:
● High photoluminescence quantum yields
● Exceptional photostability (particle and solid state)
● Broad infrared spectrum range, near-unity at NIR
● Colloidally stable
● Tunable optical properties and size
State of Development:
The proposed synthesis technique has been demonstrated, and the resulting ultrasmall HgTe quantum dots were tested in FWHM range and photoluminescent experiments using a home-built microscope. These experiments successfully characterized their behavior, supported infrared spectrum range, and bright photoluminescent quantum yield.
Related Papers:
Coffey B, Skytte E, Ahmed T, Vasileiadou E, Lin EY, Sueh Hua A, et al. Ultrasmall HgTe quantum dots with high photoluminescent quantum yields in the near and shortwave infrared . ChemRxiv. 2024; doi:10.26434/chemrxiv-2024-lnwsb.
Reference:
UCLA Case No. 2024-256
Lead Inventor:
Justin Caram, Associate Professor of Chemistry and Biochemistry