Final Report : Transformative Colloidal Nanomaterials for Mid - Infrared Devices Report

Number of Papers published in peer-reviewed journals: Final Report: Transformative Colloidal Nanomaterials for Mid-Infrared Devices Report Title The grant focused on the Photoluminescence efficiency of HgTe colloidal quantum dots. The photoluminescence quantum yield of HgTe colloidal quantum dots was measured from 1800 to 6500 cm-1 . There is a steep drop at low energy consistent with the generic gap law. Direct evidence of energy transfer to the CH stretch and overtone vibrations is apparent when temperature tunes the PL wavelength of a given sample through the vibrational resonances. Calculations based on the radiative rate and resonant energy transfer to the ligand vibrations appear to account for much of the quantum yield drop. Power dependent photoluminescence lifetime measurements on 3.7 nm particles show fast , ~50 ps, biexciton lifetime similar to other colloidal quantum dot systems of similar sizes. Various synthetic modifications have been explored to increase the PL or the size of the particles, modify the particle composition, with interesting observations but moderate improvements (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or published that acknowledge ARO support from the start of the project to the date of this printing. List the papers, including journal references, in the following categories: (b) Papers published in non-peer-reviewed journals (N/A for none) 06/11/2015