Preparation of F-passivated ZnO for quantum dot photovoltaics

For photovoltaic power generation, pn junction is the core unit. The electric field in the junction can separate and transport the electron and the hole to negative and positive electrodes, respectively. Once the pn junction ...

Scientists explore the elasticity of colloidal suspensions

Experiments reveal that under the right conditions, the elasticity of colloidal suspensions will peak at a certain value, which depends both on the deformation applied to the material and the strength of attraction between ...

Forging a dream material with semiconductor quantum dots

Researchers from the RIKEN Center for Emergent Matter Science and collaborators have succeeded in creating a "superlattice" of semiconductor quantum dots that can behave like a metal, potentially imparting exciting new properties ...

Improving crystal engineering with DNA

Northwestern investigators have demonstrated that fine-tuning DNA interaction strength can improve colloidal crystal engineering to enhance their use in creating an array of functional nanomaterials, according to a recent ...

Defying gravity with the Brazil nut effect

Physicists from the University of Utrecht and the Faculty of Physics at the University of Warsaw have observed—for the first time experimentally—the Brazil nut effect in a mixture of charged colloidal particles.

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A colloid is a substance microscopically dispersed evenly throughout another substance.

A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium). A colloidal system may be solid, liquid, or gaseous.

Many familiar substances are colloids, as shown in the chart below. In addition to these naturally occurring colloids, modern chemical process industries utilize high shear mixing technology to create novel colloids.

The dispersed-phase particles have a diameter of between approximately 5 and 200 nanometers. Such particles are normally invisible in an optical microscope, though their presence can be confirmed with the use of an ultramicroscope or an electron microscope. Homogeneous mixtures with a dispersed phase in this size range may be called colloidal aerosols, colloidal emulsions, colloidal foams, colloidal dispersions, or hydrosols. The dispersed-phase particles or droplets are affected largely by the surface chemistry present in the colloid.

Some colloids are translucent because of the Tyndall effect, which is the scattering of light by particles in the colloid. Other colloids may be opaque or have a slight color.

Colloidal solutions (also called colloidal suspensions) are the subject of interface and colloid science. This field of study was introduced in 1861 by Scottish scientist Thomas Graham.

This text uses material from Wikipedia, licensed under CC BY-SA