Spray deposition of polymeric thin-films for the inline encapsulation of organic photodiodes

In this contribution, we report the modifications incurring in the electro-optical characteristics of Organic Photodiodes exposed to ambient conditions on rigid and flexible substrates. Once the degradation of the devices is assessed and the challenges related to the use of plastic substrates are clarified, we propose an encapsulation method which is compatible with the fabrication process of solution processable electronics. The encapsulating film is obtained through the physical deposition of oxides thin films and the spray-deposition of polymeric layers. We selected Polymethylmethacrylat (PMMA) for the final tests, being the one able to guarantee best performances and easiest processability. The obtained encapsulating stack, with an overall thickness of circa 30μm, yields a retention of 40% of the original photocurrent of the OPD after 2 weeks, without hindering the ease of fabrication and the flexibility of the device.