Fujifilm organic pixel patent US8053661 has been granted recently. The patent is named "Photoelectric conversion element and imaging device" and talks about the sense layer chemistry and the pixel structure:
"In an organic photoelectric conversion element, for realizing high photoelectric conversion efficiency, low dark current and high-speed responsivity, the organic photoelectric conversion layer used preferably satisfies the following requirements.
1. In terms of high efficiency and high-speed response, the signal charge after dissociation of an exciton needs to be swiftly transmitted to both electrodes without loss. High mobility and high charge transport ability with a small number of carrier trapping sites are necessary.
2. In terms of high photoelectric conversion efficiency, it is preferred that the exciton stabilizing energy is small and the exciton can be swiftly dissociated by the effect of an externally applied electric field or an electric field generated in the inside by pn-junction or the like (high exciton dissociation efficiency).
3. In order to reduce as much a carrier generated in the inside at dark time as possible, it is preferred to select the intermediate level in the inside and select a layer structure and a material that allow the presence of less impurities working out to one of causes thereof.
4. In the case of stacking a plurality of layers, an energy level matching with the adjacent layer is required and if an energetic barrier is formed, this inhibits charge transport."
The patent has description of chemical composition of photosensitive and electron- and hole-blocking layers and also shows the 3T-like pixel schematics:
Thanks to DI for sending me the patent!