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Quantum Dot Solar Cell

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Yuyang Gao

on 9 September 2016

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Transcript of Quantum Dot Solar Cell

Quantum Dot Solar Cell
BY XiaoY
ECE662 PRESENTATION
start
Energy Diagram
Eg>CB(EC)-VB(HC)+Ec+Ev
Electron
Conductor
Hole
Conductor
Quantum
Dot
Material
Quantum dot material may include quantum dots made from a variety of materials. Illustrative but non-limiting examples of suitable quantum dot materials include materials from Groups
Ⅱ-Ⅵ Ⅲ-Ⅴor Ⅳ-Ⅵ
materials.
Examples of specific pairs of materials for forming quantum dots include but not limited to
MgO,MgS,MgSe,MgTe,CaO,CaS,CaSe,SeO,SrS,SrTe,BaO,BaS,BaSe,BaTe,ZnO,ZnS,ZnSe,ZnTe,CdO,CdS,CdSe,CdTe,HgO,HgS,HgSe,HgTe,SnS,SnSe,SnTe,PbS,PbSe,PbTe,AlN,AlP,GaN,GaP,GaAs…

QD Solar Cell
utilizing hot photogenerated carriers to produce higher photovoltages or higher photocurrents
Potential
to increase the maximum attainable thermodynamic conversion efficiency of solar photon conversion up to about 66%
Based on miniband transport and collection of hot carriers in QD array photoelectrodes before they relax to the band edges through phonon emission.
Based on utilizing hot carriers in QD solar cells to generate and collect additional electron-hole pairs through enhanced impact ionization processes.
Thank You
Yuyang Gao

College of Engineering, Technology and Architecture

University of Hartford


10/16/2013

The QD solar cell configuration
Quantum dot arrays in p-i-n cells
QD-sensitized nanocrystalline TiO
2
QDs dispersed in organic semiconductor polymer
configuration 1
The QD array is a 3-D analog to a 1-D superlattice and the miniband structures formed therein. The delocalized quantized 3-D miniband states could be expected to slow the carrier cooling and permit the transport and collection of hot carriers at the respective p and n contacts to produce a higher photopotential in a PV cell or in a photoelectrochemical cell where the 3-D QD array is the photoelectrode
configuration 2
configuration 3
In the PV cell, each type of carrier-transporting polymer would have a selective electrical contact to remove the respective charge carriers. A critical factor for success is to prevent electron–hole recombination at the interfaces of the two-polymer blends.
Quantum Efficiency
the ratio of the number of charge carriers collected by a photovoltaic cell to the number of photons of a given energy shining on the solar cell
External Quantum Efficiency
includes any efficiency that might have been lost through the transmission into the cell and any light that might have been reflected away from the cell
Internal Quantum Efficiency
refers only to the light that successfully gets converted into energy that can generate a current
Equations for Quantum Efficiency
 η=P/(E*A)
 η=
Energy Conversion Efficiency
P= Maximum Power Point
E= Input Light Irradiance
A= Area of the solar cell
Efficiency= Output / Input
The sun provides more than enough energy for all our needs, if only we could harness it cheaply and efficiently. Solar energy could provide a clean alternative to fossil fuels, but the high cost of solar cells has been a major barrier to their widespread use.
Conclusion
In this latter PV cell, dye molecules are
chemisorbed onto the surface of 10–30 nm size TiO2 particles that have been sintered into a highly porous
nanocrystalline 10–20 um TiO2 film. Upon photoexcitation of the dye molecules, electrons are very
efficiently injected from the excited state of the dye
into the conduction band of the TiO2, affecting charge
separation and producing a photovoltaic effect.

REFERENCES

1 Patent Application Publication Jan.21,2010 sheet 1 of 6;
2 Quantum dot solar cells - M.Larionova
3 Quantum dot solar cells - A.J. Nozik/Physica E 14 (2002) 115-120
4 http://en.wikipedia.org/wiki/Quantum_dot_solar_cell
Full transcript