The Isorg's organic photo detector is based on a photodiode device structure. A high EQE (External Quantum Efficiency) is obtained by blending two organic semiconductors, a p type and an n type, sandwiched between two electrodes. Excitons generated by photons are separated into electrons and holes to create an electric current that can be measured for signal processing. Isorg's home page has a nice video showing the structure of its sensor. The layers are just printed, no need in vacuum processing like in OLED.
Currently, only passive pixels may be designed, so Isorg is working on several industrial and consumer applications where passive pixels are enough. But CEA Liten (Laboratoire d’Innovation pour les Technologies des Energies Nouvelles) and Isorg are working on a hybrid structure combining organic photo detectors with organic thin film transistors, which may be available for prototyping within a year.
Isorg’s Class 10,000, 450 m2 cleanroom fab is dedicated to developing printing techniques for organic electronics on plastic and glass substrates. The company’s plans are for this fab to be able to produce thousands of 320x380 mm foils or glass plates by 2013. The manufacturing pilot line to become operational in small volumes by Q3 2012, with full automation and large-volume production slated for 2014.
Series A funding round is planned for this year. The size and source of the round will depend on how work progresses with early customers.
When I worked at Varian back in the late 90's, I visited Uniax to discuss making polymer photodiode panels on plastic substrates for use in portable x-ray imaging. They had already solved the electrical contact problem and demonstrated a line scan imager made of polymer photodiodes on glass. Somewhere in my archives I have a color image made with that scanner. It appeared that what we needed was entirely feasible. The transistors from Penn State would have been good enough for the active pixels needed in x-ray panels.
ReplyDeleteHowever, while the discussions were going on, Dupont bought Uniax and discontinued the sensor work. Fifteen-plus years later, here we are again. Maybe the French are serious about commercializing this technology.
How compare this technology to TFT based one?
ReplyDeleteI don't know any details about the French technology but the TFT issue is always mobility. Pentacene TFTS were certainly worse than A-Si:H (maybe they are better now) but they were good enough for x-ray panel use.
ReplyDeleteThe real advantage is that the polymer processing is low-temperature and could be set up to operate roll-to-roll so that all the circuitry can be done on flexible plastic. This would solve some huge problems in x-ray inspection of aircraft structures because the detectors could be made to conform to wing surfaces or rolled up and passed through access holes like film. In medical use, all portable x-ray coudl become digital because the risk of breaking the glass panels used now goes away.