SLIDE 1
Arno Smets
- 2. Spectral Utilization
Design Rules Solar Cells
- 1. Bandgap Utilization
- 3. Light Trapping
Solar Cell Operation, Performance and Design Rules Light Trapping I - - PowerPoint PPT Presentation
Solar Cell Operation, Performance and Design Rules Light Trapping I - - PowerPoint PPT Presentation
Solar Cell Operation, Performance and Design Rules Light Trapping I - Absorption and Loss Mechanisms Week 3.3.4 Arno Smets Design Rules Solar Cells 1. Bandgap Utilization Delicate Interplay 2. Spectral Utilization 3. Light Trapping Light
SLIDE 2
SLIDE 3
Light absorption: Lambert-Beer’s law
absorption Al d intensity I(d) I0 (λ)
SLIDE 4
Light absorption: Lambert-Beer’s law
) ) ( exp( ) ( ) , ( ) , ( ) ( ) , ( x I x I x I x x I
() expressed in cm-1
SLIDE 5
Absorption coefficient
107 106 105 104 103 102 101 100 200
GaAs InP Germanium Silicon
Absorption coefficient, (cm-1)
400 600 800 1000 1200 1400 1600 1800 2000
Wavelength, l (mm) Band gaps
SLIDE 6
Absorption coefficient
Depth into cell (µm) Normalized intensity [-]
0.2 20 40 60 80 100 0.4 0.6 0.8 1 0 Blue light
Red light Infrared light
SLIDE 7
Absorption coefficient
Cell depth x (µm) Generation rate (m-3)
50 100 150 200 250 1022 1021 1020 1019 1018 1017 300
Top solar cell
SLIDE 8
External quantum efficiency
1.0 Quantum efficiency Wavelength Close to window layer Through entire cell
SLIDE 9
Parasitic losses = out-side absorbing layers
p-type C-Si
Al
Al Al P++ P++
N+
n+
SLIDE 10
Parasitic losses = out-side absorbing layers
p-type C-Si
Al
Al Al P++ P++
N+
n+ 1 1
Shading
SLIDE 11
Parasitic losses = out-side absorbing layers
p-type C-Si
Al
Al Al P++ P++
N+
n+ 1
Shading
2
Reflection
1 2
SLIDE 12
Parasitic losses = out-side absorbing layers
p-type C-Si
Al
Al Al P++ P++
N+
n+ 1
Shading
2
Reflection
1 2 3 3
Parasitic absorption
SLIDE 13