This paper describes a combination of photonic annealing and compression rolling to improve the conductive properties of printed binder‐based graphene inks. High‐density light pulses result in temperatures up to 500 °C that along with a decrease of resistivity lead to layer expansion. The structural integrity of the printed layers is restored using compression rolling resulting in smooth, dense, and highly conductive graphene films. The layers exhibit a sheet resistance of less than 1.4 Ω □−1 normalized to 25 µm thickness. The proposed approach can potentially be used in a roll‐to‐roll manner with common substrates, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and paper, paving thereby the road toward high‐volume graphene‐printed electronics.

Despite the great promise of printed flexible electronics from 2D crystals, and especially graphene, few scalable applications have been reported so far that can be termed roll‐to‐roll compatible. Here we combine screen printed graphene with photonic annealing to realize radio‐frequency identification devices with a reading range of up to 4 meters. Most notably our approach leads to fatigue resistant devices showing less than 1% deterioration of electrical properties after 1000 bending cycles. The bending fatigue resistance demonstrated on a variety of technologically relevant plastic and paper substrates renders the material highly suitable for various printable wearable devices, where repeatable dynamic bending stress is expected during usage. All applied printing and post‐processing methods are compatible with roll‐to‐roll manufacturing and temperature sensitive flexible substrates providing a platform for the scalable manufacturing of mechanically stable and environmentally friendly graphene printed electronics.

Rapid and low temperature processing of mesoporous TiO 2 for perovskite solar cells on flexible and rigid substrates. Materials Today Communications, 13, 232-240.

For the preparation of electrically conductive composites, various combinations of cellulose and conducting materials such as polymers, metals, metal oxides and carbon have been reported. The conductivity of these cellulose composites reported to date ranges from 10-6 to 10 3 S cm-1. Cellulose nanocrystals (CNCs) are excellent building blocks for the production of high added value coatings. The essential process steps for preparing such coatings, i.e. surface modification of CNCs dispersed in water and/or alcohol followed by application of the dispersion to substrate samples using dip coating, are low cost and easily scalable. Here, we present coatings consisting of Ag modified CNCs that form a percolated network upon solvent evaporation. After photonic sintering, the resulting coatings are electrically conductive with an unprecedented high conductivity of 2.9 9 10 4 S cm-1. Furthermore, we report the first colloidal synthesis that yields CNCs with a high degree of Ag coverage on the surface, which is a prerequisite for obtaining coatings with high electrical conductivity.

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