| Abstract: |
| In this work, we propose, implement and analyze a theoretical model of a Poly(3-hexylthiophene-2,5-diyl)-organic semiconductor
device (P3HT) for subretinal prosthetic implants presently under development at the CNST@PoliMi, Milano Italy (https://iit.it/centers/cnst-polimi).
The model, based on the Drift-Diffusion nonlinear PDE system, aims at unraveling the interaction among the phenomena of light impinging on device
surface, exciton generation in the P3HT bulk, exciton dissociation into electron and hole charge carriers, and charge recombination at the device
interfaces with Indium Tin Oxide (ITO) and electrolyte solution, respectively. The spatial accuracy of model finite element discretization
is investigated against an analytical solution. Results demonstrate the numerical scheme to verify optimal error estimates in both H1 and L2 norms.
Then, the model is solved to predict the time evolution of the electric potential elicited at the interface with the ITO electrode as a function
of illumination conditions. Model simulations predict an electron accumulation at the interface with the electrolyte solution and a sign of
electric potential at ITO interface strongly affected by the light stimulus. These preliminary results agree with experimental measurements
and may help shed light on prosthesis photoactivation in both in vivo and in vitro conditions. |
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