Quantum Nanomaterial & Device Laboratory(QNDL) specializes in the synthesis of colloidal semiconductor nanocrystals, commonly referred to as 'Quantum Dots.' Our research focuses on the structural engineering of quantum dots to enhance their performance in various optoelectronic applications, including light-emitting devices, lasers, and luminescent solar concentrators. We possess the capability to precisely control the dimensions, shapes, and compositions of these quantum dots according to specific requirements. 

Within our facility, we explore a diverse range of semiconductors comprised of binary compounds such as CdSe, ZnSe, ZnTe, InP, AgInS2, AgGaS2, as well as their alloys. Through collaborative efforts with spectroscopic analysts worldwide, we endeavor to unveil the underlying principles governing the behavior and properties of quantum dots. This interdisciplinary approach allows us to delve deeper into the secrets of these nanocrystals, paving the way for advancements in various technological fields.

Talos™ F200i is a flexible and compact 200 kV FEG Scanning Transmission Electron Microscope (S/TEM), which is designed for fast, precise and quantitative characterization of nano-materials. It enables nano-analysis of materials based on high data quality, fast acquisition, and simplified, easy and automated operation.

Talos F200i is equipped with the 4k x 4k CMOS Camera for both low and high-dose applications. In addition, it combines outstanding  quality  in  high-resolution  STEM  and  TEM  imaging  with  dual Energy Dispersive X-ray Spectroscopy (EDS). This dual EDS is made for such situations, where limited signal is available for instance the case when analyzing very sensitive samples.

The Agilent 5800 ICP-OES (Inductively Coupled Plasma – Optical Emission Spectrometer) is a robust and highly efficient analytical instrument engineered for the rapid, precise, and quantitative determination of elemental concentrations across a vast range of sample types. It enables comprehensive elemental analysis, delivering exceptional data quality, fast sample throughput, and simplified, intuitive operation. 

The Agilent 5800 ICP-OES is equipped with advanced optical systems and robust plasma technology, designed for both routine and challenging applications. In addition, it offers axial and radial plasma viewing capabilities, combining outstanding sensitivity for trace elements with the ability to handle high matrix samples. This versatility makes the Agilent 5800 ideal for situations where a wide range of elemental concentrations need to be accurately quantified, such as in environmental monitoring, food safety, or material science.

Quantum Nanomaterial & Device Laboratory(QNDL) fabricate optoelectronic device by using QDs synthesized in our lab. There are many applications using QDs. For example, QD solar cell, QD LSC, QD detector, QD laser and QD-LEDs are well known applications. Based on  narrow spectrum line width of QDs, QD-LEDs produce very pure red, green and blue light. Based on this characteristics, QD-LEDs are promising applications. In our group, we not only fabricate device, but also characterize and analyze device operation. This analysis provides deep understanding on operation mechanism of QD-LEDs and suggests design protocol for high performance QD-LEDs. 

Many features of the single exciton fluorescence have been extensively studied for aiding theories to applications and understanding phenomena within QDs. Beyond the essential optical characterizations, such as absorption and emission spectroscopy, we have extended the range of characterization techniques to explore carrier dynamics over time scales ranging from microsecond to picosecond. Time-resolved photoluminescence (TrPL) spectroscopy of QD ensembles reveals new features when the QD is excited with a pulse laser. 

Observation of individual QDs gives us a chance to learn about new phenomena, which cannot be obtained from ensemble spectroscopy. The focus is on the mechanisms underlying the dynamic inhomogeneities—spectral diffusion and fluorescence intermittency—observed in the emission properties of single QDs. Individual dots have the tendency of turning on and off with a statistical pattern, and the phenomena can be recorded via a highly sensitive single-photon detector. 

These measurements offer a glance into the capacity of single QD spectroscopy in unraveling the intricacies of single semiconductor QD optical dynamics. The narrow emission spectra of a QD have been obtained from electron-multiplying charge-coupled devices (EMCCDs). Spectral diffusion refers to discrete and continuous changes in the emitting wavelength as a function of time. With a Hanbury-Brown-Twiss setup with two single-photon detectors, we also measure single QD biexciton physics.