We report room-temperature ordered multiphoton emission from multiexciton states of single CdSe(CdZnS) core(-shell) colloidal nanocrystals (NCs) that are synthesized by wet chemical methods. Spectrally and temporally resolved measurements of biexciton and triexciton emission from single NCs are also presented. A simple four level system models the results accurately and provides estimates for biexciton and triexciton radiative lifetimes and quantum yields.

Printed on paper containing at least 50% wastepaper, including 10% post consumer waste.However the lengthy thermal process used in that tool is not viewed as a commercially scalable process, primarily due to its extended process time. Therefore the effort to use an RTP process was launched at the beginning of the project in order to develop a faster absorber formation process for eventual transfer to Solexant's pilot process line. Characterization ToolsSolexant has an array of analytical tools in-house that were used extensively throughout this project effort. These tools include scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron beam induced current (EBIC), electron dispersive spectroscopy (EDS), white-light interferometry, Infrared Thermography, optical absorption spectroscopy, xray fluorescence (XRF), capacitance-voltage (C-V), current-voltage (I-V) and light-biased quantum efficiency (QE). We had collaborative efforts with NREL's Measurement and Characterization group for lock-in Infrared Thermography, SEM, focused ion beam (FIB)-SEM and EDS, STEM, EBIC, cathodoluminescence (CL) and Raman.

In this paper, we report on our progress on developing heavy metal free (or Cdfree) QD-LEDs for all three colors. With improvement in synthesis, we have developed high quantum yield heavy metal free quantum dots (more than 95% for red and green and more than 80% for blue), with peak wavelengths suitable for BT.2020. Building upon these high-performance quantum dots and through novel device structure design and optimization we have demonstrated high efficiency heavy metal free QD-LEDs with EQE = 16.9%, 13%, 9% for red, green, and blue, respectively. Specifically, we report a systematic study on the impact of shell thickness to the device efficiency performance.

Quantum dots (QDs) have already been shown to achieve >90% BT.2020 color gamut in LCD displays using (QDEF®) Quantum Dot Film technology. In this paper, we report that by further engineering of the quantum dot materials, >90% BT.2020 is possible in a RoHS‐compliant package. This is possible by using a combination of cadmium‐free and low‐cadmium quantum dots.

Electroluminescent QD-LEDs with heavy metal free InP and ZnTeSe quantum dots are one of the most promising future display technologies. Here we report improved efficiency of 19.6%, 17.6%, and 11.5% for red, green, and blue QD-LEDs, respectively. The blue QD-LEDs exhibit true blue emission with peak wavelength of 453 nm.