Monochromator for wavelength-dependent solar cell chracterization

One of the primary areas of research in the Organic Electronic Materials and Devices group at Dalhousie University is the fabrication and optimization of organic solar cells. Our recent studies of both simple bilayer heterojunction devices, and linearly graded mixed layer, or "bulk heterojunction", devices revealed a surprising time dependence of the photovoltaic response under continued illumination. We were able to identify and understand the cause of this behaviour by illuminating the devices with three different LEDs - the first with a wavelength absorbed by only one of the two organic materials, the second absorbed by both, and a third absorbed by only the second of the two organic layers. This method worked very well, in this case, but the methodology would be generally applicable and much more accurate if a continuously variable wavelength light source (from the near UV, over the visible, and into the near IR) with a narrow peak width were available. We are therefore requesting a monochromator, which we will couple to our existing solar simulation lamp, to provide such a source.