Alternative Technology for Infrared Photodetectors – TAPIR

The methodology consists of combining modeling and experiment in order to limit the trial / error approach. The construction of the project and the choice of partners is based on this approach
The synthesis is guided by quantum chemistry and the feedback with experimental results is used to refine the model
The architecture of the photodetectors is guided by the modeling of the devices as well as the model is refined by the experimental data resulting from the advanced physical characterizations carried out on the new semiconductors
The formulation of the inks and the surface treatment relies on the skills of the chemistry and electronics laboratories taking into account from the beginning the industrial constraints of ISORG

The first materials synthesized have the expected characteristics for the absorption and the charge carrier mobility. The model used for the prediction of strength oscillator and energy transitions is validated
We have built up the tools for the optoelectronics characterization of the photodetectors (static and dynamic) as well as a setup of thermally stimulated current to study the mechanisms of degradation.

As soon as the dark current issues are solved (pinhole in the active layer, residual doping of organic semiconductors) we will be able to advance in the modeling of NIR photodetectors to optimize the architecture of the devices
The transfer to the industrial tool will follow

1 article in Scientifique reports
5 talks in international conferences
2 communications in national conferences

The Human / Machine Interfaces (HMI) market is a fast growing business, always looking for innovations. In particular, promising application of HMI in the sector of health industry would require non-contact systems, in order to limit the spread of pathogens. Sensors based on organic photodiodes are one of the most innovative technologies allowing to address this market, at a very competitive cost. The ISORG Company is currently working in this area, developing a complete and original technology, as well as the corresponding printed electronics production line. However, contactless HMI interfaces would be even more efficient if they employ Near Infra Red (NIR) photodiodes, instead of visible one, to avoid unwanted interaction with natural or artificial light. But, despite the progress of NIR absorbing organic semiconductor for solar application, no efficient organic NIR photodiodes have been achieved so far.
The TAPIR project aims at proposing an original solution to this challenge. A complementary team of 6 partners, used to work together, has been selected to this task. Moreover, the project organization has been designed following two general principles. First of all, physically based modeling should be used to guide technology development as much as possible. This methodology aims at avoiding the poorly efficient "trial / error" approach. Secondly, industrial constraints such as solubility of materials, solvents and stability, should be considered at every stages of the project, in order to reduce as much as possible the time needed to transfer academic research results into industrial products.
More specifically, the technical project will be organized as follow: first of all, a suitable NIR absorbing organic material will be carefully designed and synthesized (and not simply copied from the solar cell research), considering the two most plausible options (i.e. a soluble small molecule for the partner ICG-AM2N or a polymer for the partner IPREM). To this aim, sophisticated quantum chemistry simulations (performed by ISM) will be used to guide efficiently the effort of synthesis. Several original and promising molecular structures to be tested have already been identified by the consortium, and presented in the proposal. A particular care will be dedicated to the solubility of these new molecules into green solvents, as required by the industrial production.
The resulting molecules will be then introduced and tested, at the research level, by IMS, inside a complete photodiode. Again, electro optics simulations will be performed by the laboratoire Hubert Curien, in order to identify the more suitable device architecture, and to help achieving a satisfactory trade off between dark current and quantum efficiency. Last but not least, molecules and devices will be transferred into the industrial production line of ISORG, in order to achieve a complete prototype by the end of the project. The issue of material and device stability in operating conditions will be addressed since the early stage of the project, in particular with the direct involvement of a joint PhD student between IMS and ISORG (not required in this project).
The project will be led by the Organic Electronics group at IMS in Bordeaux, one of the national leaders in the area of organic electronics, one of the founder of GDR « Electronique Organique », the Labex AMADEUS and the Equipex ElorPrintTec.