کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
80603 | 49391 | 2007 | 4 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy Efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy](/preview/png/80603.png)
The current–voltage characteristic and the performance of organic bulk-heterojunction solar cells are very sensitive to small variations in the production steps or environmental influences. In our experiments, we found a large variation of the short-circuit current, which does not correspond to the device thickness as one might expect. The fill factor of some devices is below 25% under illumination, while the best devices have a fill factor of about 70%. Electrical impedance spectroscopy can provide information about the conductivity of different regions within the device. In earlier measurements, it was observed that devices with a thick absorber layer might consist of a conductive bulk region and a very poorly conductive depletion region at the metal contact. Using a standard semiconductor device model, it is shown in this paper that this reduces the charge collection efficiency under short-circuit conditions, as there is no electrical field in the bulk region, supporting the charge separation. For devices with the low fill factor, a thin-current limiting layer under forward bias can be identified by electrical impedance spectroscopy and is suggestive of a corroded metal contact.
Journal: Solar Energy Materials and Solar Cells - Volume 91, Issue 5, 6 March 2007, Pages 390–393