Pixelated cathode substrate system overview (depreciated)
The pixelated cathode design allows for a greater degree of flexibility for the multitude of device architectures being developed while also reducing series resistance and allowing extended lifetime testing.
Note this system is now depreciated and has been replaced by the 8 pixel OPV substrate system, which has lower series resistance and additional pixels.
The schematics below show the layout of the substrates along with the available deposition shadow masks. The pixelated cathode substrates come with a single large ITO anode pad along with six cathode connection strips which can be used to connect up to six small cathodes or one large cathode. The active area deposition mask can be used to evaporate materials onto just the active areas. The active area is defined by the overlap between the ITO anode pad and the cathodes.
Note that for solution processed devices (spin/drop cast) that the outermost two pixels often have non-uniform thickness due to edge effects (this is not a problem for evaporated layers). These pixels are also subject to much more rapid edge ingress which can cause significantly faster degradation but also be useful for separating out intrinsic and extrinsic degradation processes.
Pixelated Cathode Substrates with Small Pixels
Pixelated Cathode Substrates with Large Pixel