PGS Lab – Exploring the Infrared Quantum Dots

Welcome to the PGS Lab!

Please use the navigation on the top to find information about our research, people, and publications.

Photovoltaic Devices

We demonstrate sensitive thermal imaging with HgTe colloidal quantum dot (CQD) photovoltaic detectors by integrating the HgTe CQDs with plasmonic structures. A detectivity of 4 E 11 Jones is achieved at 80 K.

Mid-Wave Infrared Photodetectors

Using a modified PV device architecture, we report up to 2 orders of magnitude improvement in the sensitivity of the HgTe CQD photodetectors

Slow Auger Relaxation in HgTe CQDs

The biexciton lifetimes in HgTe colloidal quantum dots are measured as a function of particle size.

Synthesis of HgTe CQDs

Nonaggregating HgTe colloidal quantum dots are synthesized without thiols as stabilizing ligands. The dots are spherical with a size tunability from 4.8 to 11.5 nm.

Electrochemistry of Colloidal Quantum Dot Films

The absolute positions of the energy levels of colloidal quantum dots of Hg(S, Se, Te), which are of interest as mid-infrared materials, are determined by electrochemistry.

Xingyu won the graduate student silver award and the best student presentation award for EL02 at MRS spring 2024!

Welcome to Jinlei Feng and Shraman Saha, who join the group as first-year students!

Xingyu and Ananth’s paper on intraband cascade electroluminescence is published in Nature Photonics!

Looking for PhD students and Postdocs

We are looking for strongly motivated PhD students and Postdocs interested in our current experimental projects:

Synthesis and characterization of “low toxicity” colloidal quantum dots, core/shells, films and inorganic matrix, with the characterization of the mid-infrared absorption and photoluminescence.
Simulation and microfabrication of optically enhancing structures in the mid-infrared
Studies of electronic, thermal, and thermoelectric transport of small gap quantum dot solids. Exploring the noise and the limits of the mobility in the state-resolved transport regime.
HgTe and HgSe colloidal quantum dot state of the art mid-infrared photodetector and emitter, using basic considerations to drive synthesis, processing and device architecture.
Laser spectroscopy, time resolved recombination dynamics, Auger and stimulated emission studies, using a 1kHz, 1054nm, 6 ps laser system, with nonlinear crystal for mid-infrared wavelength conversion and mid-infrared up conversion.

Please contact Professor Philippe Guyot-Sionnest by email pgs@uchicago.edu, include a CV, and a brief but specific description of why you are interested in our research topics.

Congrats to PGS for being elected AAAS fellow!

Congrats to Philippe Guyot-Sionnest (aka PGS) for being elected a fellow of the American Association for the Advancement of Science (AAAS). Philippe thanks the friends who nominated him, the AAAS fellows who supported the nomination, and all the students and postdocs who made the contributions that led to the group’s recognition.

Lab contributions include bright core/shell quantum dots that led to their use in bioimaging and TV displays, intraband quantum dot spectroscopy that may lead to mid-infrared detectors and emitters, and electronic doping and ligand exchange strategies that impart ohmic electrical conductivity to films of quantum dots. Prior to joining UChicago, PGS developed nonlinear optical probes for molecular spectroscopy and ultrafast studies of liquid and solid interfaces.

Philippe’s AAAS citation is for distinguished contributions to the physics and chemistry of nanomaterials, particularly fluorescent core-shell nanoparticles”. This was a seminal contribution by Margaret Hines, who was the first Chemistry PhD student in the group, and it started with a stunningly green looking solution of CdSe/ZnS quantum dots that Margaret synthesized one late evening in the lab.

Xingyu receives the Olshansky Graduate Student Travel Award for presenting her work at MRS fall 2022!

Congratulations to John, who won Best Poster at the ACS conference!

Xingyu and John’s paper demonstrating the first mid-infrared quantum dot LED is published in ACS Nano! Congratulations!

Chris’s article on thermodynamic limits to HgTe quantum dot detectors is published in Journal of Electronic Materials!

Ananth receives the Windt Graduate Student Travel Award 2022! He will be presenting his work at the MRS Spring 2022 Conference

Welcome to Xingyu Shen, who joins the group as a first year student!

Chris’s review article on many-body dynamics is published in Chemical Reviews!

Matt receives the William E. Spicer – Thomas N. Casselman Award

Congratulations to Matt for his award for best student paper at the U.S. Workshop on the Physics and Chemistry of II-VI Materials (a.k.a. the II-VI workshop)!

Xin and Matt’s paper highlighted as a “breakthrough for infrared camera technology”

Xin and Matt devised a detector using quantum dots tuned to detect different parts of the infrared spectrum, allowing dual-band infrared imaging. You can read more about it in this UChicago News article, and the technical paper was published in Nature Photonics.

Menglu Receives The Yodh Prize

Congratulations to Menglu! She has been awarded the Yodh Prize for outstanding graduate work in experimental physics.

Matt Receives The Elizabeth R. Norton Prize

Congratulations to Matt! He has received the Elizabeth R. Norton Prize for excellence in chemistry research.