Nanomaterials Flashcards
Materials that are at least with one dimension (width, length or height) sized on a nanoscale.
Nanomaterials
Objects with all three external dimensions at the nanoscale.
Nanoparticles
Range of the nanoscale is __ - __ nm
1-100 nm
1 nm = 1 x __ m
10^-9
_____ is the engineering and manipulation of materials at the molecular level.
Nanotechnology
Materials that are converted to nanoscale through processes.
Man-made Nanoparticles
Volcanic ash, soot from forest fires and dust are examples of _____ nanoparticles.
Naturally-occurring
Engineered nanomaterials/nanoparticles are intentionally produced and designed with very specific properties related to _____ , _____ , _____ , and ______.
Shape, Size, Surface properties, Chemical properties
Particles created at the nanoscale have different _____ and _____ properties than larger particles of the same material.
Chemical, Physical
Materials with structure at the nanoscale often have unique _____ , _____ , or _____ properties.
Optical, Electronic, Mechanical
The behavior of nanomaterials may depend more on _____ than particle composition itself.
Surface Area
_____ is one of the principal factors that enhance reactivity, strength, and electrical properties.
Relative Surface Area
_____ nanomaterials have unique electrical, optical, photonic and mechanical properties.
Semiconductor
Semiconductor _____ are tiny light-emitting particles on the nanometer scale.
Nanocrystals
Effects of particle size in the electronic properties are _____ and _____.
Effect of Surface Area, Quantum Confinement
It is basically defined as the energy band that comprises of valence electrons present in the outermost shell of an atomic structure.
Valence Band
It is defined as that energy band that consists of free electrons that are responsible for conduction.
Conduction Band
Valence band and conduction band are separated by a certain amount of energy known as the _____.
Forbidden Energy Gap
The gap between bands determines whether a substance is a/an _____ , a/an _____ , or a/an _____.
Metal, Semiconductor, Insulator
As the particle gets _____ , the band gap gets _____.
Smaller, Larger or Larger, Smaller
Among elements, only _____ , _____ , and _____ , all of which have 4 valence electrons, are semiconductors.
Silicon, Germanium, Graphite
_____ have no band gap.
Metals
_____ have small band gap.
Semiconductors
_____ have the largest band gap.
Insulators
Smaller particle size absorbs light of a _____ frequency and _____ wavelength.
Higher, Lower
As the crystals are made smaller, the material progressively changes color until it looks _____ because no visible light is absorbed.
White
Larger particle size absorbs light of a _____ frequency and _____wavelength.
Lower, Higher
_____ can absorb most of solar spectrum. Can be used in low-cost organic solar cells because of its semiconductor property.
Fullerene
_____ have great mechanic properties and are the strongest one-dimensional material.
Carbon Nanotubes
_____ has extremely high tensile strength, conducts electricity, transparent, and is the thinnest two-dimensional material in the world.
Graphene
Semiconductor particles with diameters
in size range of 1 - 10nm are called
_____.
Quantum Dots
Particles with large band gaps (Eg > 3.0 eV) need high-energy _____ light to excite electrons into the conduction band.
Ultraviolet
Particle with small band gaps (Eg = 0.5 eV) absorbs all wavelengths of _____ light.
Visible
