Surface Plasmon Modulation in CuP Nanocrystals.

We demonstrate modulation of the surface plasmon resonance in nonstoichiometric copper phosphide nanocrystals using spectroelectrochemical methods. Application of an anodic potential resulted in a blue-shift of the surface plasmon resonance and an incremental increase in its extinction coefficient. Conversely, upon application of a cathodic potential, the surface plasmon band red-shifted and reduced in intensity.

Electrophoretic Deposition of Single Nanoparticles.

The controlled assembly of colloid particles on a solid substrate has always been a major challenge in colloid and surface science. Here we provide an overview of electrophoretic deposition (EPD) of single charge-stabilized nanoparticles. We demonstrate that surface templated EPD (STEPD) assembly, which combines EPD with top-down nanofabrication, allows a wide range of nanoparticles to be built up into arbitrary structures with high speed, scalability, and excellent fidelity.

Temperature Dependence of the CdS Bandgap in the Extreme Confinement Regime.

A non-empirical equation describing the effect of size on the temperature dependence of the optical bandgap of CdS (d/d) is obtained on the basis of the Brus equation. Intriguingly, we find that d/d diverges strongly from bulk values only within the "extreme confinement" (EC) regime. We conducted both experimental and theoretical investigations of the absorption spectra of CdS clusters and quantum dots as a function of temperature above room temperature.

Room Temperature Bias-Selectable, Dual-Band Infrared Detectors Based on Lead Sulfide Colloidal Quantum Dots and Black Phosphorus.

A single photodetector capable of switching its peak spectral photoresponse between two wavelength bands is highly useful, particularly for the infrared (IR) bands in applications such as remote sensing, object identification, and chemical sensing. Technologies exist for achieving dual-band IR detection with bulk III-V and II-VI materials, but the high cost and complexity as well as the necessity for active cooling associated with some of these technologies preclude their widespread adoption. In this study, we leverage the advantages of low-dimensional materials to demonstrate a bias-selectable dual-band IR detector that operates at room temperature by using lead sulfide colloidal quantum dots and black phosphorus nanosheets.

Spectroelectrochemistry of CdSe/CdZnS Nanoplatelets.

We report an unexpected enhancement of photoluminescence (PL) in CdSe-based core/shell nanoplatelets (NPLs) upon electrochemical hole injection. Moderate hole doping densities induce an enhancement of more than 50% in PL intensity. This is accompanied by a narrowing and blue-shift of the PL spectrum.