Gradient Multi-Layer nanofilm
Encyclopedia
Gradient Multi-Layer nano-film
is an assembly of Quantum Dot
layers with a built-in gradient
of nanoparticle size, composition or density.
Properties of such nanostructure
are finding its applications in design of solar cell
s and energy storage
devices.
The GML nano-structure can be embedded in the organic material (polymer
), or can include Quantum Dots made of two or more types of material.
Photovoltaic applications
The GML nanofilm only 100 nanometers thick can absorb the entire Sun spectrum (0.3-2.0+ eV). At the same time, gradient of the quantum dots size can create a gradient of the electro-chemical potential, acting as an equivalent of built-in electric field
inside a nanofilm. This enhances transport of electron
s and holes
, and improves internal quantum efficiency (IQE)
and photocurrent
.
Manufacturing
The industrial manufacturing of GML nanofilms represents a challenge. Traditional methods of building nanostructured materials (like spin coating
) can't form GML nanostructures, while more effective methods like Atomic Layer Deposition
(ALD) or Langmuir-Blodget "microchemical" method. are expensive.
The cost-efficient alternative for manufacturing GML nano films is FP ("Flying Particles") method .
Nanomaterials
Nanomaterials is a field that takes a materials science-based approach to nanotechnology. It studies materials with morphological features on the nanoscale, and especially those that have special properties stemming from their nanoscale dimensions...
is an assembly of Quantum Dot
Quantum dot
A quantum dot is a portion of matter whose excitons are confined in all three spatial dimensions. Consequently, such materials have electronic properties intermediate between those of bulk semiconductors and those of discrete molecules. They were discovered at the beginning of the 1980s by Alexei...
layers with a built-in gradient
Gradient
In vector calculus, the gradient of a scalar field is a vector field that points in the direction of the greatest rate of increase of the scalar field, and whose magnitude is the greatest rate of change....
of nanoparticle size, composition or density.
Properties of such nanostructure
Nanostructure
A nanostructure is an object of intermediate size between molecular and microscopic structures.In describing nanostructures it is necessary to differentiate between the number of dimensions on the nanoscale. Nanotextured surfaces have one dimension on the nanoscale, i.e., only the thickness of the...
are finding its applications in design of solar cell
Solar cell
A solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect....
s and energy storage
Energy storage
Energy storage is accomplished by devices or physical media that store some form of energy to perform some useful operation at a later time. A device that stores energy is sometimes called an accumulator....
devices.
The GML nano-structure can be embedded in the organic material (polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
), or can include Quantum Dots made of two or more types of material.
Photovoltaic applications
The GML nanofilm only 100 nanometers thick can absorb the entire Sun spectrum (0.3-2.0+ eV). At the same time, gradient of the quantum dots size can create a gradient of the electro-chemical potential, acting as an equivalent of built-in electric field
Electric field
In physics, an electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding...
inside a nanofilm. This enhances transport of electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s and holes
Electron hole
An electron hole is the conceptual and mathematical opposite of an electron, useful in the study of physics, chemistry, and electrical engineering. The concept describes the lack of an electron at a position where one could exist in an atom or atomic lattice...
, and improves internal quantum efficiency (IQE)
Quantum efficiency of a solar cell
Quantum efficiency is the ratio of the number of charge carriers collected by the solar cell to the number of photons of a given energy shining on the solar cell. QE therefore relates to the response of a solar cell to the various wavelengths in the spectrum of light shining on the cell. The QE is...
and photocurrent
Photocurrent
Photocurrent is the current that flows through a photosensitive device, such as a photodiode, as the result of exposure to radiant power.The photocurrent may occur as a result of the photoelectric, photoemissive, or photovoltaic effect....
.
Manufacturing
The industrial manufacturing of GML nanofilms represents a challenge. Traditional methods of building nanostructured materials (like spin coating
Spin coating
Spin coating is a procedure used to apply uniform thin films to flat substrates. In short, an excess amount of a solution is placed on the substrate, which is then rotated at high speed in order to spread the fluid by centrifugal force...
) can't form GML nanostructures, while more effective methods like Atomic Layer Deposition
Atomic layer deposition
Atomic layer deposition is a thin film deposition technique that is based on the sequential use of a gas phase chemical process. The majority of ALD reactions use two chemicals, typically called precursors. These precursors react with a surface one-at-a-time in a sequential manner...
(ALD) or Langmuir-Blodget "microchemical" method. are expensive.
The cost-efficient alternative for manufacturing GML nano films is FP ("Flying Particles") method .