Programm Photovoltaik Ausgabe 2009 ... - Bundesamt für Energie BFE

5/10
Flat Plate Concentrator sample composition:
Sample number Fluorescent Dyes Concentration in %
ECN778
Red305 0.01
ECN747C Yellow83 0.004
Sample number Fluorescent Dyes Concentration in %
ECN779
Red305 0.01
Yellow170 0.0045
Sample number Fluorescent Dyes Concentration in %
ECN780
Red305 0.01
ECN749 CRS040 0.003
The UV-VIS absorptions of the FPC samples were measured during the 470 nm LED light soaking
period to monitor changes over time in the dyes:
2.5
2
1.5
1
0.5
FPC ECN778 (0.01% Red305 + 0.004% Yellow83) aged in LED 470 nm
Start
16 hr
43 hr
159 hr
824 hr
LED 470 nm
0
300 350 400 450 500
Wavelength in nm
550 600 650 700
Graph 1: UV-VIS spectra of sample
ECN778 followed over time during the
470 nm LED light exposure.
The degradation of the Yellow83 dye is clearly visible by the reduction of the absorption peaks around
440 and 465 nm, whereas the Red305 peak at 575 stays practically at the same intensity over the
illumination time.
2.5
2
1.5
1
0.5
FPC ECN779 (0.01% Red305 + 0.0045% Yellow170) aged in LED 470 nm
Start
16 hr
43 hr
159 hr
824 hr
LED 470 nm
0
300 350 400 450 500
Wavelength in nm
550 600 650 700
Graph 2: UV-VIS spectra of sample
ECN779 followed over time during the
470 nm LED light exposure.
The degradation of the Yellow170 dye is clearly visible by the reduction of the absorption peak at 505 nm,
whereas the Red305 peak at 575 stays almost at the same intensity over the illumination time.
2.5
2
1.5
1
0.5
FPC ECN780 (0.01% Red305 + 0.003% CRS040) aged in LED 470 nm
Start
16 hr
43 hr
159 hr
824 hr
LED 470 nm
0
300 350 400 450 500
Wavelength in nm
550 600 650 700
Graph 3: UV-VIS spectra of sample
ECN780 followed over time during the
470 nm LED light exposure.
The UV-VIS spectrum of the FPC samples show clearly a degradation always and only the yellow dye,
seen as the lowering of the absorption level in the range of 400 to 550 nm.
Short-circuit photocurrent monitored over time of the 3 samples exposed in 470 nm LED light:
25
20
15
10
5
0
FPC aging in LED lamp at 470 nm
FPC ECN778: 0.01% Red305 0.004% Yellow83
FPC ECN779: 0.01% Red305 0.0045% Yellow170
FPC ECN780: 0.01% Red305 0.003% CRS040
0 100 200 300 400 500 600 700 800 900
Elapsed time in hr
FULLSPECTRUM, T. Meyer, Solaronix
157/290
Graph 4: Short-circuit current in function
of the elapsed time in function of the
elapsed time in the 470 nm LED
exposure of the side attached crystalline
Si solar cell, measured in the 470 nm
LED light.