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Full-Text Articles in Engineering
Development Of Low Temperature, Aqueous Synthesis Method Of Lead Sulfide Quantum Dots, Albert Nakao, Colin Yee
Development Of Low Temperature, Aqueous Synthesis Method Of Lead Sulfide Quantum Dots, Albert Nakao, Colin Yee
Materials Engineering
Quantum dots have become an active area of research in the past decade due to their unique properties. Quantum confinement effects allow for efficient spectral conversion and size tunable fluorescence and absorption peaks. Near infrared spectral converting lead sulfide quantum dots have potential applications in solar power, biological imaging and communications technology. However at Cal Poly, lead sulfide dots have not been synthesized. The quantum dot synthesis currently adapted at Cal Poly encompasses organometallic precursors at high reaction temperatures, producing cadmium selenium dots. The organometallic approach has been found to produce nanocrystals with high quality photoluminescence, but due to its …
Fluorescence Characterization Of Quantum Dots For Use As Biomarkers, Logan M. Grimes
Fluorescence Characterization Of Quantum Dots For Use As Biomarkers, Logan M. Grimes
Materials Engineering
Fluorescence profiles of quantum dots (QDs) were characterized to select the ideal QDs for encapsulation in phospholipids for use as biomarkers to selectively adhere to cancer cells. QDs were synthesized and extracted 0, 30, 60, and 90 seconds after precursor compounds were mixed. These extractions were isolated by extraction time. Portions from each vial were coated in a zinc sulfide shelling procedure, leaving at least half of the QD solution unshelled. These samples were characterized over four days to monitor fluctuations in fluorescence. This was done utilizing an Ocean Optics spectrometer in conjunction with Spectra Suite software. The central wavelength, …
Development Of A High Precision Quantum Dot Synthysis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Cell, Harry Lafferty, Jonny Hoadley
Development Of A High Precision Quantum Dot Synthysis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Cell, Harry Lafferty, Jonny Hoadley
Materials Engineering
Quantum dots show great potential for use as spectral converters in solar cells, lighting applications and biological imaging. These applications require precise control of quantum dot size to maximize performance. The fluorescence profile of quantum dots in solution correlates directly with particle size. An alternative, high precision process was developed for the synthesis of cadmium-selenide quantum dots using a microfluidic reactor and fluorescence flow through cell. The process required creating separate cadmium and selenium precursors that were then mixed in a nitrogen environment at 17± 1°C. Using an NE-300® syringe pump, the solution was pumped through a microfluidic reactor …
Application Of Quantum Dots Onto Glass Wafers As A Feasibility Test For The Spectral Down Conversion Of Uv Light For Solar Cells, Anthony Fong
Materials Engineering
Quantum dots have the ability to convert high energy photons into multiple lower energy photons. Down conversion of such high energy photons from sources such as UV light can be beneficial for applications on solar cells which waste much of the energy in the form of thermalization. To test this theory, a solar cell was hooked up to an Amprobe Solar Analyzer and tests were run to compare power output with and without the presence of quantum dots. Additionally, quantum dots were spin coated onto a glass wafer to determine its adhesion ability. Spectrometer readings were taken of the wafer …
Improving Solar Cell Performance Using Cdse/Zns Core/Shell Quantum Dots In A Spectral Conversion System, Buddy Bump
Improving Solar Cell Performance Using Cdse/Zns Core/Shell Quantum Dots In A Spectral Conversion System, Buddy Bump
Materials Engineering
Solar cells have been found to absorb light more efficiently and effectively when the energy of incoming photons matches the electronic band gap of the solar cell. Spectral conversion of light from UV to lower energy wavelengths can improve solar cell efficiency an estimated 14.5%. Cadmium Selenium/Zinc Sulfide Core/Shell quantum dots have been successfully embedded in PDMS silicone elastomer. Using a Keithley 2400 Electrometer with Labview software, voltage and current characteristics have been recorded in steps of 10 mV with a wait time of 250 ms on a commercially available solar cell using an artificial solar spectrum created by a …
The Design And Manufacture Of A Microfluidic Reactor For Synthesis Of Cadmium Selenide Quantum Dots Using Silicon And Glass Substrates, Peter Gonsalves
The Design And Manufacture Of A Microfluidic Reactor For Synthesis Of Cadmium Selenide Quantum Dots Using Silicon And Glass Substrates, Peter Gonsalves
Materials Engineering
A microfluidic reactor for synthesizing cadmium selenide (CdSe) quantum dots (QDs) was synthesized out of silicon and Pyrex glass. Microfabrication techniques were used to etch the channels into the silicon wafer. Holes were wet-drilled into Pyrex glass using a diamond-tip drill bit. The Pyrex wafer was aligned to the etched silicon wafer and both were anodically bonded to complete the microfluidic reactor. Conditions for anodic bonding were created by exposing the stacked substrates to 300V at ~350oC under 5.46N of force. Bulk CdSe solution was mixed at room temperature and treated as a single injection. The syringe containing …
Characterization Of A Pdms Microfluidic Reactor For Synthesizing Quantum Dots, Brian Harley
Characterization Of A Pdms Microfluidic Reactor For Synthesizing Quantum Dots, Brian Harley
Materials Engineering
A PDMS microfluidic reactor was made in Cal Poly’s class 1000 clean room for the purpose of synthesizing quantum dots. The device master mold was made from a silicon substrate and SU-8 features 50μm tall. The PDMS reactor was cast from that mold. The flow rates of fluid through the channels, heating of the reactor and pressure in the reactor were measured in order to characterize the potential for synthesizing quantum dots. Flow rates of 20 mL/hr through 4 mL/hr were tested to characterize the consistency of amount of time the fluid remains in the reactor at a constant flow …