Transparent Conductive Electrodes (TCE), optically transparent to visible light and electrically conductive, begin to have a great industrial interest for the development optoelectronic devices, such as, liquid crystal displays (LCDs), organic light emitting diodes (OLEDs), organic photovoltaic (OPV) cells and touch panels. Currently, Indium Tin Oxide (ITO) is the most widely used thanks to its excellent opto-electrical properties, including the low sheet resistance (R_s) (10–15 Ω/sq) and the high transparency (>85% 550 nm) [1].

To achieve the current optoelectronic devices market requirements, industrially scalable production methods of high quality electrodes with advanced functional properties such as high optical transparency and electrical conductivity is vastly demanded via low-cost approaches. Besides the functional properties (conductivity and transparency), flexibility begins to be an important criteria. This needs is even more pronounced for the new competitive applications such as stretchable electronics. They require low-cost, flexible, transparent electrodes that may be employed at large-scale with printing or roll-to-roll coatings. In this case, ITO becomes less competitive because of its high intrinsic and processing costs (Physical Vapor Deposition). New constituents have thus emerged as alternative to ITO such as metal nanowires, graphene, carbon nanotube and intrinsically conductive polymers [2, 3]. Silver nanowires (AgNWs) exhibit  functional properties comparable to that of ITO combined with a high flexibility, and the ability to be deposited by printing technologies at room temperature and air atmosphere.  They are adaptable to different substrates nature (glass or polymers) with dissimilar mechanical properties (brittle or flexible) and roughness via low-cost and scalable manufacturing techniques. Importantly, inkjet printing is a promising technique for large-scale printed flexible and stretchable electronics. However, the development of printable optoelectronics devices based on AgNWs for commercialization, still has to overcome several processing challenges.

The current work concerns organic photovoltaic on cells flexible polymer substrates, and with innovative transparent electrodes. Efficient inkjet printing of highly concentrated AgNW ink was successfully realized with large active surface (100*100 mm²). Ink formulations and printing conditions have been studied and optimized for electrical and transparence properties.

This step was essentially performed with a design of experiments. The AgNW layer has also been considered with a series of physico-chemical (UV-vis, IRTF, Raman) and morphological (OM, SEM, AFM) characterizations to define the properties/structure interrelationships and develop a more comprehensive optimization. To conclude, the optimal conditions lead to thin functional electrodes with high reproducibility.  The solar cells based on these electrodes exhibit promising power conversion efficiencies exceeding 4 %.