Lead Sulfide Nanocrystal‐Polymer Composites for Optoelectronic Applications

Abstract

Summary: Nanocomposite films were prepared by two methods in which lead sulfide (PbS) nanocrystals were contained in an organic matrix. One method used a wet chemical synthesis of the nanocrystals in the direct presence of a polymer, where the polymer controlled nanocrystal growth. The second method was gaseous deposition of nanocrystals into the organic phase. The two methods were similar in that the nanocrystals in the composites were free from surfactant capping layers that otherwise would add an interfacial region between the nanocrystal and the organic matrix. The gaseous deposition technique had several advantages over the wet chemical synthesis in that it allowed direct control over nanocrystal size and density, improved flexibility in the choice of organic phase, and was compatible with lithographic methods.

Narrow bandgap colloidal metal chalcogenide quantum dots: synthetic methods, heterostructures, assemblies, electronic and infrared optical properties

“…Asunskis et al [34][35][36] have studied the nonlinear optical properties of PbS QD-doped polymer composites using NC material grown following the earlier methods of Hines 30 and the Bawendi 37 group. More recently they have adopted the hot injection method 38 using lead acetate and squalene/oleic acid as the metal precursor and ligands, respectively, and thioacetamide in dimethylsulfoxide to furnish the sulfur source.…”

Stability and aging studies of lead sulfide quantum dot films: Photoabsorption, morphology, and chemical state characteristics

“…The oxidation state analysis of lead was performed using the Pb 4f transition in the 138e145 eV binding energy region. The sulfur oxidation state analysis used the S 2s transition at approximately 225e232 eV [24,25].…”

Cluster Beam Deposition of Lead Sulfide Nanocrystals into Organic Matrices

“…However, the use of an organic or other matrix is needed to isolate the deposited clusters and preserve their distinct structures without problems of NC agglomeration (20).…”

“…CBD is used here for the gaseous deposition of PbS NCs codeposited into an evaporated organic, which controls the NC size distribution, surface chemistry, and shape by preventing unwanted agglomeration (20). Two different organic matrices were used in PbS NC/organic film fabrication, R-sexithiophene (6T) and titanyl phthalocyanine (TiOPc), verifying that the CBD method is applicable to any evaporable matrix.…”