Ternary-/hetero-nanocrystals: a facile one-pot colloidal route for controlled synthesis of ternary AgFeS sub(2) nanocrystals, which have a band gap of 1.21 eV, is presented for the first time. Such ...ternary AgFeS sub(2) nanocrystals can transform to Ag sub(2)S-Fe sub(7)S sub(8 ) heterodimers by internal thermal reaction at elevated temperature, providing a new route to synthesize semiconductor hetero-nanostructures.
A study is presented on improving the absorption of the PbS colloidal quantum dot films using plasmonic scattering. Unlike previous methods that include high temperature annealing, an integrated ...circuits compatible method of introducing colloidal gold nanoparticles to PbS film during the spin deposition process is developed. The devices are composed of eight layers of PbS and gold nanoparticles are spin casted after the fourth layer that places them in the middle, sandwiched between PbS films in order to avoid electrical shorts between the fingers. Two different solutions of gold nanoparticles in citrate, 0.1% and 0.01%, are used to fabricate two different devices. Introducing 0.01% Au nanoparticles in PbS film increases the responsivity by 2.6-fold, whereas introducing 0.1% Au nanoparticles results in a 6.5-fold increase in responsivity.
The emergence of collective motion among interacting, self-propelled agents is a central paradigm in non-equilibrium physics. Examples of such active matter range from swimming bacteria and ...cytoskeletal motility assays to synthetic self-propelled colloids and swarming microrobots. Remarkably, the aggregation capabilities of many of these systems rely on a theme as fundamental as it is ubiquitous in nature: communication. Despite its eminent importance, the role of communication in the collective organization of active systems is not yet fully understood. Here we report on the multi-scale self-organization of interacting self-propelled agents that locally process information transmitted by chemical signals. We show that this communication capacity dramatically expands their ability to form complex structures, allowing them to self-organize through a series of collective dynamical states at multiple hierarchical levels. Our findings provide insights into the role of self-sustained signal processing for self-organization in biological systems and open routes to applications using chemically driven colloids or microrobots.
Janus particles, colloid‐sized particles with two regions of different surface chemical composition, possess energetic interactions that depend not only on their separation but also on their ...orientation. Research on Janus and colloidal particles that are chemically patchy in even more complicated fashion has opened a new chapter in the colloid research field. This article highlights recent progress in both experiment and theory regarding synthesis and self‐assembly of Janus particles, and tentatively outlines some areas of future opportunity.
Janus particles, colloid‐sized particles with two regions of different surface chemical composition, possess energetic interactions that depend not only on their separation but also on their orientation. Research on Janus and colloidal particles that are chemically patchy in even more complicated fashion has opened a new chapter in the colloid research field. This report highlights recent progress in both experiment and theory regarding synthesis and self‐assembly of Janus particles, and tentatively outlines some areas of future opportunity.
Polyvinylpyrrolidone, PVP, stabilized Pd–M (M
=
Ag, Au, Cu, Ni and Pt) alloy colloids are successfully prepared by γ-irradiation in aqueous solution. PVP-stabilized Pd–M colloids are characterized by ...field-emission transmission electron microscopy (FE-TEM) and energy dispersive X-ray spectroscopy (EDXS). The catalytic efficiency of Pd and Pd–M alloy colloids is analyzed for the reduction of 4-nitrophenol in aqueous solution at room temperature. The catalytic efficiency of Pd–M alloy nanoparticles takes the following order: Pd
>
Pd–Cu
∼
Pd–Ni
>
Pd–Ag
∼
Pd–Au
>
Pd–Pt.
PDF
