STUDY OF AQUEOUS-PROCESSABLE FULL-ORGANIC AND HYBRID ORGANIC/INORGANIC NANOPARTICLE-BASED FILMS FOR SUSTAINABLE PHOTOVOLTAIC APPLICATIONS

Organic photovoltaics offer low environmental impact energy from a widely available and naturally replenished source, with relevant advantages of low-cost, easy fabrication, solution processability, light weight, transparency, and mechanical flexibility. Unfortunately the large amount of harmful halogenated and/or aromatic solvents used in the device fabrication process limited the industrial implementation of this technology so far. The need to develop a sustainable approaches for the preparation of aqueous-processable active layers for OPV manufacturing has become increasingly urgent, starting from the halogenated organic solvent reduction in the device production. The application of aqueous colloidal solutions for active layer nano-assembling could represent an approach for a dramatic reduction of halogenated organic solvents use in multilayered device processing. Moreover exploiting the self-assembly capability of properly tailored amphiphilic copolymers it is possible to control the nanoscale morphology of the sandwiched layers in the final devices ensuring to achieve highly efficient OPVs. On this basis, we recently synthesized a rod-coil amphiphilic block copolymer based (ABCP) on a low band-gap copolymer (poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl], PCPDTBT, an electron-donor material), with an hydrophilic coil block, poly-4-vinylpyridine (P4VP)-based, allowing to prepare aqueous suspensions of full-organic nanoparticles (NPs) using the miniemulsion method with blends of the ABCP and a fullerene derivative electron-acceptor, that were employed in the fabrication of sustainable active layers (reduction of chlorinated solvents, no need of repeated dialysis purification steps and water saving). Moreover, preliminary results on the study of the use of noble metal NPs embedded in polymeric matrices for the fabrication of conductive layers by means of different techniques (spin-coating, micro-contact printing, etc.) will be also presented.