「 Quantum dot solar cells 」 A. J. Nozik, Physica E 14 (2002) 115-120. YOSHIDA Lab. Hiroaki...
18
「 Quantum dot solar cells 」 A. J. Nozik, Physica E 14 (2002) 115- 120. YOSHIDA Lab. Hiroaki KAMIOKA
-
Upload
jacob-porter -
Category
Documents
-
view
222 -
download
1
Transcript of 「 Quantum dot solar cells 」 A. J. Nozik, Physica E 14 (2002) 115-120. YOSHIDA Lab. Hiroaki...
「 Quantum dot solar cells 」A. J. Nozik, Physica E 14 (2002) 115-120.
YOSHIDA Lab.Hiroaki KAMIOKA
contentscontents
Introduction Necessity of Quantum dot solar cells
Ways to increase conversion efficiency
Proposals of Quantum dot solar cell configuration
Summary
Present source of energy supply
Present source of energy supply
Environmental pollution
Environmental pollution
Eco-friendly new energyEco-friendly new energy
Solar energy generationSolar energy generation
BAD!!BAD!!
Introduction Necessity of Quantum dot solar cellsIntroduction Necessity of Quantum dot solar cells
Conversion efficiency of current solar cellsConversion efficiency of current solar cells
About ２０％
About ２０％
currentlycurrently
About ３１％
About ３１％
Theoretical limitTheoretical limit
Technical progressTechnical progress
Current solar cells can't cover the demand of energy on earthCurrent solar cells can't cover the demand of energy on earth
Quantum dot solar cells
Quantum dot solar cells
Necessity for new technological idea!!
Quantum Dot (it is a semiconductor whose excitons are confined in all three spatial dimensions)
bulk Quantum dot
Discretization of energy level
Discretization of energy level
Present source of energy supply
Present source of energy supply
Environmental pollution
Environmental pollution
Eco-friendly new energyEco-friendly new energy
Solar energy generationSolar energy generation
BAD!!BAD!!
Introduction Necessity of Quantum dot solar cellsIntroduction Necessity of Quantum dot solar cells
Conversion efficiency of current solar cellsConversion efficiency of current solar cells
About ２０％
About ２０％
currentlycurrently
About ３１％
About ３１％
Theoretical limitTheoretical limit
Technical progressTechnical progress
Current solar cells can't cover the demand of energy on earthCurrent solar cells can't cover the demand of energy on earth
Quantum dot solar cells
Quantum dot solar cells
Necessity for new technological idea!!
Quantum Dot (it is a semiconductor whose excitons are confined in all three spatial dimensions)
bulk Quantum dot
Discretization of energy level
Discretization of energy level
WW ＝ ＝ × × Higher photovoltages :V
or
Higher photocurrents :I
Way to increase conversion efficiency Way to increase conversion efficiency
VV II W:wattV :voltageI :current
Quantum dot
Function of quantum dot for the solar cellsHigher photovoltages from “discretization”
e
h
e
h
V ２
V1 ＜ V ２
Higher photovoltages
V1
Bulk
Ec: bottom of conducton band
Ev: top of valence band
Function of quantum dot for the solar cellsHigher photocurrents from “Impact ionization”
Higher photocurrents
Function of quantum dot for the solar cellsHigher photovoltages from “Separation”
normalnormal
Separation!!Separation!!
Higher photocurrents
balk Quantum dot
Quantum dot arrays in p-i-n cells
intrinsic P-typeN-type
Quantum dot-sensitized nanocrystalline TiO2 solar cells
Quantum dots dispersed in organic semiconductor polymer matrices
Summary
If quantum dot cells get achieved, conversion efficiency can increase incredibly.
It is important to get hot electrons without loss or to get many electrons by impact ionization.
It is the most important that this theory is just an expectation.
