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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〔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.〕 and energy storage devices.〔(Quantum dot ultracapacitor and electron battery ). Freepatentsonline.com. Retrieved on 2012-05-22.〕 The GML nanostructure 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 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.〔(Microchemical nanofactories ). Freepatentsonline.com. Retrieved on 2012-05-22.〕 are expensive. The cost-efficient alternative for manufacturing GML nano films is FP ("Flying Particles") method.〔(Method of forming a flexible nanostructured material for photovoltaic panels ). 〕 ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gradient multilayer nanofilm」の詳細全文を読む スポンサード リンク
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