Increase of Third-Order Nonlinear Optical Activity of PbS Quantum Dots in Zeolite Y by Increasing Cation Size

Size Dependence of the Resonant Third-Order Nonlinear Refraction of Colloidal PbS Quantum Dots

Due to their high resonant third-order nonlinear response, lead sulfide quantum dots (QDs) are potential materials for applications in the field of nonlinear optics. In this paper, we implement the Z-scan method to study the resonant nonlinear response of lead sulfide QDs in colloidal solutions. We managed to measure the purely intrinsic resonant nonlinear response, free of thermal contribution. We report that the lead sulfide QD third-order nonlinear response per QD shows an unconventional increase. A figure of merit for QD nonlinearity grows as a power function with a factor of 2.9.

Dual emissions from MnS clusters confined in the sodalite nanocage of a chalcogenide-based semiconductor zeolite

A new host–guest hybrid system with MnS clusters confined in a chalcogenide-based semiconductor zeolite was for the first time constructed and its photoluminescence (PL) properties were also investigated.

Broadband optical limiting response of a graphene-PbS nanohybrid

Graphene-based materials have shown promising nonlinear optical properties in the visible range. To extend their nonlinear optical response to the near infrared (NIR) region, we prepared a new nanohybrid consisting of uniform PbS quantum dots (QDs) attached on the reduced graphene oxide, named rGO-PbS, via a facile, low-cost, and phosphine-free method. The rGO-PbS nanohybrid exhibited superior optical limiting properties to either graphene oxide or PbS QDs upon both 532 nm and 1064 nm excitation in the nanosecond laser pulse regime, which is attributed to the synergetic effects stemming from charge transfer between the two components. Meanwhile, the thin films containing the rGO-PbS nanohybrid dispersed in polymethylmethacrylate (PMMA) also showed excellent optical limiting properties with high transparency, implying the potential applications of this hybrid material in broadband nonlinear optical devices.

Morphological control of PbS grown on functionalized self-assembled monolayers by chemical bath deposition

We have investigated the chemical bath deposition (CBD) of PbS on functionalized alkanethiolate self-assembled monolayers (SAMs) using time-of-flight secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. The deposition mechanism involves both cluster-by-cluster and ion-by-ion growth. The dominant reaction pathway and the chemical composition and morphology of the deposited layer are dependent on both the SAM terminal group and the experimental conditions. On -COOH-terminated SAMs, three types of crystallites are observed: nanocrystals formed by heterogeneous ion-by-ion growth, larger needle-like particles, and ~2 μm particles deposited by homogeneous cluster-by-cluster deposition. The nanocrystals nucleate at Pb(2+)-carboxylate surface complexes, and so strongly adhere to the substrate. On -OH- and -CH3-terminated SAMs, only the micrometer-sized particles are formed by a cluster-by-cluster deposition mechanism. These particles do not adhere strongly to the SAM surface and can be easily removed. SIMS and XPS analyses indicate that the larger needle-like crystals and micrometer-sized particles are composed of oxidized lead sulfide and lead oxides, while the nanocrystals are composed of ≥85% PbS. Using sonication-assisted CBD, we demonstrate that PbS is deposited by ion-by-ion growth alone on -COOH-terminated SAMs. The deposited film is more compact with a smaller grain size and is >90% PbS.

Novel luminescent hybrids prepared by incorporating a rare earth ternary complex into CdS QD loaded zeolite Y crystals through coordination reaction

Novel luminescent hybrids were assembled by incorporating a rare earth (Eu, Tb), mercaptan acid and 1,10-phenanthroline ternary complex into CdS loaded zeolite Y through coordination reaction.