Gradient multilayer (GML) nanofilm 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 cells[1][2][3] and energy storage devices.[4]
The GML nanostructure can be embedded in the organic material (polymer), or can include quantum dots made of two or more types of material.
![](http://up.wiki.x.io/wikipedia/commons/c/c1/GMLnanofilm.png)
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 electrochemical potential, acting as an equivalent of built-in electric field inside a nanofilm. This enhances transport of electrons 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.[5] are expensive.
See also
editReferences
edit- ^ Holm, Timothy P.; Cheng Chieh Chao; Prinz, Fritz B. (2009). "Energy transfer between quantum dots of different sizes for quantum dot solar cells". 2009 34th IEEE Photovoltaic Specialists Conference (PVSC). p. 85. doi:10.1109/PVSC.2009.5411731. ISBN 978-1-4244-2949-3.
- ^ Reddy, Damoder and Gilman, Boris Nanophotovoltaic Device with Improved Quantum Efficiency. US Patent Application 20080142075. Freepatentsonline.com. Retrieved on 2012-05-22.
- ^ Quantum dot solar cell with quantum dot bandgap gradients. Freepatentsonline.com. Retrieved on 2012-05-22.
- ^ Quantum dot ultracapacitor and electron battery. Freepatentsonline.com. Retrieved on 2012-05-22.
- ^ Microchemical nanofactories. Freepatentsonline.com. Retrieved on 2012-05-22.