Diseño y fabricación de módulos fotovoltaicos orgánicos impresos sobreinyectados

This work has been developed during the internship at EURECAT, centre tecnològic de Catalunya, in the Functional Printing & Embedded Devices unit.

The main objective of the project was to manufacture organic photovoltaic devices (OPV) and incorporate them into injected plastic parts, without losing their functionality. Firstly, the different layers that make up the OPVs have been optimised. Secondly, devices have been manufactured on rigid and flexible substrates using printing techniques (Dr. Blade, Slot-Die and screen printing) and thermal evaporation. Thirdly, the use of thermoplastic polyurethane (TPU) and polycarbonate (PC) for the injection of OPV devices has been compared using a thermoplastic polymer injection molding; the samples have been previously prepared with backing film, barrier film and different types of adhesives.

Thanks to the characterisation of the samples by J-V curves, 4-point, EQE, absorbance and LBIC measurements, the effect of the different manufacturing and injection process parameters of the devices has been monitored. Regarding the configuration of the devices, it has been determined that the PM6 donor material has a higher absorbance than PTQ10, although PTQ10 is able to generate a higher potential difference. In addition, the addition of IDIC to the tested systems improves the charge extraction. A system has also been established to optimise the thickness of the photoactive layer (PAL) according to the OPV materials. In this line, it is concluded that semi-transparent OPVs need higher PAL thickness to achieve photocurrents approaching those obtained with evaporated layers. As for printed electrodes, inks based on silver nanowires (AgNWs) or PEDOT:PSS have been identified as having great potential to replace ITO as the bottom electrode, due to their low resistivity and high transmittance; however, issues related to stack compatibility, roughness and layer stability remain to be solved. Finally, OPV devices fabricated with ITO and Flextrode (commercial Ag and PEDOT:PSS electrode) have shown a satisfactory tolerance to the injection process, maintaining an average of ~90% of their original efficiency. It is concluded that OPV devices with PM6 as active layer donor material and TPU as injected thermoplastic material achieve higher functionality. On the other hand, samples injected with PC show a drastic decrease in their functionality, presumably due to the degradation of the active layer at higher injection temperatures.