Room-Temperature, Multigram-Scale Synthesis and Conversion Mechanism of Highly Luminescent Lead Sulfide Quantum Dots

Abstract

PbS quantum dots (QDs) are attractive near-infrared (NIR) materials, but traditional synthetic methods require inert atmosphere and/or high temperature. Herein we develop a facile, room-temperature synthetic route for in situ halide passivated PbS QDs through controllable reactions between lead halide, N,N′-diphenyl thiourea, and oleyamine (OLA) in toluene. Contrast experiments and theoretical calculations reveal that the OLA plays a bifunctional role as a mild base to initiate the formation of PbS monomers and as a dynamic ligand to control the crystallization of PbS QDs and further ligand exchange. The oleic acid-capped PbS QDs exhibit high photoluminescence quantum yields up to 45%. The scaled-up synthesis on multigram scales shows great batch-to-batch consistency. We further demonstrate high-power NIR light-emitting diodes using the PbS QDs as color converters, delivering NIR optical power of 9.2 mW at 160 mA. This work provides a simple and versatile synthetic route for high-quality PbS QDs and boosts the applications of NIR materials.

Unravelling the intricacies of solvents and sulfur sources in colloidal synthesis of metal sulfide semiconductor nanocrystals

“…9a. 132 If the equilibrium is one the isothiocyanate side and a metal carboxylate is added the reaction proceeds via a cyclic rearrangement which results in the respective amide and carbonyl sulfide. 133 This carbonyl sulfide can react with the metal ions and decompose to form metal sulfide nanomaterials (Fig.…”

One‐pot, easy and scalable synthesis of large‐size short wave length IR emitting PbS quantum dots

“…[1][2][3][4][5] QDs offer various types of applications, including photodetectors, [6][7][8][9][10][11] photovoltaics, solar cells, [12][13][14][15] transistor lasers, and light-emitting diodes. 16,17 Out of the large variety of QDs, those that display optical properties in the short-wave infrared (SWIR) spectrum, spanning from approximately 1-3 μm (1000-3000 nm), have garnered special research interest due to their specific applications, encompassing night vision, biomedical imaging, optical communication, and more. [18][19][20][21] Presently, cutting-edge SWIR technologies predominantly rely on photosensitive materials like InGaAs and HgCdTe.…”

Pseudohalogen Ammonium Salt-Assisted Syntheses of Large-Sized Indium Phosphide Quantum Dots with Near-Infrared Photoluminescence

“…The preparation method of the InP QDs@SEBS composite film is presented in Figure a, and the detailed fabrication process can be found in the Supporting Information. The resultant NIR-LED devices are then manufactured by a combination of intrinsically stretchable InP QDs/SEBS composites and high-power blue GaN chips . The photographs of the transparent pristine SEBS and InP/SEBS composite films are also presented in Figure a.…”