Accession Number : AD1048401


Title :   Ligand Enhanced Upconversion of Near-Infrared Photons with Nanocrystal Light Absorbers


Descriptive Note : Journal Article - Open Access


Corporate Author : Department of Chemistry Riverside United States


Personal Author(s) : Huang,Zhiyuan ; Simpson,Duane E ; Mahboub,Melika ; Li,Xin ; Tang,Ming L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1048401.pdf


Report Date : 04 Mar 2016


Pagination or Media Count : 4


Abstract : We designed and synthesized a tetracene derivative 4-(tetracen-5-yl)benzoic acid (CPT) as a transmitter ligand used in PbS/PbSe nanocrystal (NC) sensitized upconversion of near infrared (NIR) photons. Under optimal conditions, comparing CPT functionalized NCs with unfunctionalized NCs as sensitizers, the up conversion quantum yield (QY) was enhanced 81 times for 2.9 nm PbS NCs from 0.021 to 1.7 , and11 times for 2.5 nm PbSe NCs from 0.20 to 2.1 . The surface density of CPT controls the solubility of functionalized NCs and the upconversion QY. By increasing the concentration of CPT in the ligand exchange solution, the number of CPT ligand per NC increases. The upconversion QY is maximized at a transmitter density of 1.2 nm2 for 2.9 nm PbS, and 0.32 nm2 for 2.5 nm PbSe. Additional transmitter ligands inhibit photon upconversion due to triplet triplet annihilation (TTA) between two neighboring CPT molecules on the NC surface. 2.1 is the highest reported QY for TTA-based photon upconversion in the NIR with the use of earth-abundant materials.


Descriptors :   photons , crystal structure , LIGANDS , transmitters , optical properties , ENERGY ABSORBERS , nanotechnology , NEAR INFRARED RADIATION


Subject Categories : Optics


Distribution Statement : APPROVED FOR PUBLIC RELEASE