Synthesis of Core/Shell/Shell Quantum Dots with Improved Luminescent and Semi-Conducting Properties

Technology #31141

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structural model of a CdS/Cd,Zn1_xS:Mn!ZnS core/shell/shell of the present invention
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Researchers
Swadeshmukul Santra, Ph.D.
Soumitra Kar
Managed By
Andrea Adkins
Assistant Director 407.823.0138
Patent Protection

Excitation band-gap tuning of dopant based quantum dots with core-inner shell-outer shell

US Patent 7,687,800 B1

Excitation band-gap tuning of dopant based quantum dots with core-inner shell outer shell

US Patent 7,776,630 B1

Excitation band-gap tuning of dopant based quantum dots with core-inner shell-outer shell

US Patent 7,855,091 B1
Publications
GdIII-Functionalized Fluorescent Quantum Dots as Multimodal Imaging Probes
Advanced Materials, 2006, 18, 2890

The technology represents methods for the synthesis of quantum dots with a core/shell/shell structure and compositions which allow one to customize the particles excitation band-gaps. It also provides a variety of semi conducting alloys for creating the core of the quantum dots as well as several metal dopants for the shell.

Quantum dots (semiconductor nanoparticles) exhibit both strong semi-conducting properties and the ability to absorb light in the ultraviolet region. They are currently used for bio-imaging applications, in electronics, solar cells and in optoelectronics. While quantum dots make great fluorescent probes for bio-imaging and disease detection, the downside to the current art is that they can only absorb light in the ultraviolet (UV) region, a range which is extremely harmful to living tissue; while the rest of the electromagnetic spectrum is not absorbed for solar applications. The semi-conducting and electronic properties of the dots are heavily reliant upon their outer shell and structure. Consistency in the outer shell provides more uniform quantum dots with less defects and more desirable properties. When quantum dots are doped with various metals and/or protected by a semiconductor shell their electronic and light absorbing properties are significantly improved.

Technical Details

Researchers at UCF have created a new method of synthesizing quantum dots with a core/shell/shell structure. These quantum dots consist of a semi-conducting alloy core with a metal doped shell and an additional metal sulfide shell. Due to the unique core/shell/shell structure there is a vast improvement over previously synthesized quantum dots. Combining two semiconductor materials in the core allows for overlap of their excitation spectra (range of light absorbed). This allows for selection of a specific wavelength range based on the core alloy and the ratio between the two materials. This wavelength range is much greater than previously created quantum dots, allowing for better excitation using less harmful, non-UV light or for capturing a wider range of the solar light spectrum. Also, by altering the metal dopant present in the semi-conductor lattice, different wavelengths of bright visible light are emitted upon excitation. This property makes these quantum dots ideal as fluorescent probes and possible electroluminescent materials. The design allows for better bio-imaging, with less damage to living tissue and a wider range of biological applications. The synthesis provided herein is simple, easily scalable, customizable, inexpensive and produces extremely small (3 nm) nanocrystals.

Benefits

  • Simple and inexpensive synthesis at room-temperature
  • Large scale production
  • Ultra small and highly reproducible nanocrystals
  • Surface can easily be modified to functionalize particles for any task
  • Extremely bright phosphor-makes a better electroluminescent material
  • Large separation between excitation and emitted light for bio-imaging applications

Applications

  • High performance solar cells
  • Ultra small bio-imaging probes
  • Electroluminescent material
  • Optics
  • Displays
  • Solid state devices


Additional Technology Numbers: 31680, 31847