Bragg mirrors are widely applied in optical and photonic devices due to their capability of light management. However, the fabrication of Bragg mirrors is mainly accomplished by physical and chemical vapor deposition processes, which are costly and do not allow for lateral patterning. Here, the fabrication of Bragg mirrors by fully inkjet printing is reported. The photonic bandgap of Bragg mirrors is tailored by adjusting the number of bilayers in the stack and the layer thickness via simply varying printing parameters. An ultrahigh reflectance of 99% is achieved with the devices consisting of ten bilayers only, and the central wavelength of Bragg mirrors is tuned from visible into near‐infrared wavelength range. Inkjet printing allows for fabricating Bragg mirrors on various substrates (e.g., glass and foils), in different sizes and variable lateral patterns. The printed Bragg mirrors not only exhibit a high reflection at designed wavelengths but also show an outstanding homogeneity in color over a large area. The approach thus enables additive manufacturing for various applications ranging from microscale photonic elements to enhanced functionality and aesthetics in large‐area displays and solar technologies.

Mints emit diverse scents that exert specific biological functions and are relevance for applications. The current work strives to develop electronic noses that can electronically discriminate the scents emitted by different species of Mint as alternative to conventional profiling by gas chromatography. Here, 12 different sensing materials including 4 different metal oxide nanoparticle dispersions (AZO, ZnO, SnO2, ITO), one Metal Organic Frame as Cu(BPDC), and 7 different polymer films, including PVA, PEDOT:PSS, PFO, SB, SW, SG, and PB were used for functionalizing of Quartz Crystal Microbalance (QCM) sensors. The purpose was to discriminate six economically relevant Mint species (Mentha x piperita, Mentha spicata, Mentha spicata ssp. crispa, Mentha longifolia, Agastache rugosa, and Nepeta cataria). The adsorption and desorption datasets obtained from each modified QCM sensor were processed by three different classification models, including Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA), and k-Nearest Neighbor Analysis (k-NN). This allowed discriminating the different Mints with classification accuracies of 97.2% (PCA), 100% (LDA), and 99.9% (k-NN), respectively. Prediction accuracies with a repeating test measurement reached up to 90.6% for LDA, and 85.6% for k-NN. These data demonstrate that this electronic nose can discriminate different Mint scents in a reliable and efficient manner.

Roll‐to‐roll hot embossing is exploited for the fabrication of 1D nanogratings and 2D nanopillar arrays. Critical structure diameters as low as 150 nm and distances down to 50 nm are replicated in a polystyrene foil using flexible nickel shims, which are made using electron beam lithography and subsequent electroplating. The high quality of the as‐fabricated structures is proven by their application in two key nanophotonic components. After evaporation of 250 nm of Alq3:DCM on 1D nanogratings using grating periods between 375 and 415 nm, we can realize tunable organic DFB lasers emitting between 604 and 665 nm. 2D nanopillar arrays are covered with a thermally evaporated Au layer and integrated in microfluidic chips for surface‐enhanced Raman measurements. High and homogeneous enhancement of the Raman signal is achieved using rhodamine 6G as exemplary analyte. For polystyrene nanopillar arrays with pillar diameters of 190 nm, a spacing of 50 nm, and a height of 100 mm coated with a 70 nm thick Au layer, an analytical enhancement factor of ≈4.3 × 104 is demonstrated. The presented work shows the versatility of roll‐to‐roll hot embossing for the low‐cost and large‐area fabrication of nanostructures.

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