Printed ferroelectric devices are ideal candidates for self-powered and multifunctional sensor skins, contributing to a sustainable smart future.

Macroelectronic components combining different classes of devices often suffer from the high complexity and costs of the manufacturing processes. The printing of an active‐matrix sensor network using only five functional inks is demonstrated. The result is an all‐printed monolithically integrated touchless input interface, including ferroelectric sensor pixels, organic transistors for impedance matching, and an electrochromic display.

A monolithically integrated bifunctional frontplane is introduced to large area electronics. The bifunctional frontplane element is based on a composite foil of piezoelectric ceramic lead titanate nanoparticles embedded in a ferroelectric poly(vinylidene fluoride trifluoroethylene) polymer matrix. Bifunctionality to pressure and temperature changes is achieved by a sequential, area selective two-step poling process, where the polarization directions in the nanoparticles and the ferroelectric polymer are adjusted independently. Thereby, sensor elements that are only piezoelectric or only pyroelectric are achieved. The frontplane foil is overlaid on a thin-film transistor backplane. Our work constitutes a step toward multifunctional frontplanes for large area electronic surfaces.

The performance of organic thin-film transistors (OTFT) for flexible, low cost and disposable "plastic" electronic products advances rapidly: various organic semiconductors display hole or electron carrier mobilities [1] that compare favorably with those of hydrogenated amorphous silicon, [2] the inorganic counterpart for such applications as flexible displays, [3,4] smart cards and radio frequency identification tags, [5,6] nonvolatile memories [7] and sensors. [8,9] The possibility for tailoring functional organic materials, bears potential towards novel electronic products such as smart skins, [10] smart textiles [11] and "invisible electronics", [12] where multiple functionalities, portability and ubiquitous integration is requested. In this context diverse properties of organic thin-film devices are inevitable such as lightweight, low power consumption, low operationvoltage and compatibility with diverse substrates.[12]Reducing the threshold voltage and the subthreshold swing is essential for operating OTFTs at low-voltage levels. When combined with very low gate leakage currents, OTFTs may also become a key element in high-end sensor applications, such as flexible touch pads and screens or thermal imaging tools for night vision, surveillance or for the detection of undesired heat loss paths in buildings.The aforementioned transistor parameters not only critically depend on the thickness and the dielectric properties of the gate insulator, [12][13][14] but also on the trapped charge densities at the interface between these materials. The selection of semiconductors and gate insulators with excellent interface properties is currently the challenge in the quest for improving the performance of OTFTs.Here we show that bottom-gate OTFTs based on the organic semiconductor pentacene and high-k nanocomposite gate dielectrics, exhibit transistor performances with very low gate leakage currents, subthreshold swings close to the theoretical limit, and low-voltage battery operation. The subthreshold swings of OTFTs with different organic and hybrid gate dielectrics follow an inverse dependence on the gate capacitance as is expected by standard MOS theory. The trapped charge carrier density at the interface between the semiconductor and the dielectric surpasses that of the SiO 2 -pentacene interface, being close to the average trap densities in the SiO 2 -Si interface in metal oxide semiconductor transistors. [15] We also report the first application of these OTFTs in an optothermal light sensor. We describe the transistor, the temperature sensitive fluorinated polymer, their combination in an integrated circuit, and the application of this circuit as a thermal infrared sensor and as a switch that can be operated by a laser pointer. Figure 1 shows the structure of low-voltage organic transistors with high dielectric constant (high-k) oxide-polymer nanocomposites. Al 2 O 3 or ZrO 2 were chosen as high-k dielectric materials, combined with poly(a-methyl styrene) (PaMS) or poly(vinyl cinnamate) (PVCi) to form a smooth and ...

High-performance pentacene organic thin-film transistors with double layers of the terpolymer electret poly(vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene) and the polymer poly(vinyl cinnamate) as a gate dielectric are reported. The electret is a high-k dielectric polymer with a static dielectric constant of ε=14. The transistors show an intrinsic field-effect mobility in the range of μi=1cm2∕Vs and an on- to off-current ratio of about 105. High-k polymer gate dielectrics seem promising for organic nonvolatile memory and sensor field-effect transistors.

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Recently developed flexible active matrix sensors employ organic and large area electronics to enable artificial sensing skin applications. In the proof‐of‐concept presented here, an active matrix proximity sensor‐array is formed by monolithic integration of screen‐printed sensors with organic transistors on a single sheet of a polymer film, using only seven industrially scalable patterning steps. A ferroelectric co‐polymer of polyvinylidendifluoride (PVDF) serves as the pyro‐sensor material, and bottom‐gate top‐contact organic thin film transistors switch the sensors during operation. An on/off ratio well above 103 and a low off‐current below 8 × 10−11 A of the organic transistors result in a dynamic range of 44 dB and allow to detect a human hand approaching to a distance of 20 cm with a signal‐to‐noise ratio of 28 dB. A basic matrix operation is demonstrated by the correct tracking of a moving human hand.

Most flexible piezoelectric transducers have a vertical setup with top and bottom electrodes, which does not enable the selective, directional detection of mechanical stimuli. Here we present a paradigm shift in the design of such transducers by placing the electrodes in a single layer and fully embedding them in a ferroelectric layer. This approach enables a selective detection of in-plane strains with a linear, orientation-dependent response. Our transducers feature microstructured, densely interdigitated electrodes embedded in the ferroelectric copolymer P(VDF-TrFE) and show an in-plane strain sensitivity of up to 8.3 nC %−1 (21.3 V %−1), while being 23 times less sensitive to transversal loading, compared to vertical setup devices. The embedded electrodes cause a strong anisotropy for in-plane strain coupling and make it possible to distinguish both the bending orientation and the bending intensity on a time-variable curvilinear surface. A high power density of 2.3 mW cm−3 was achieved during a periodic bending movement at 90 Hz. In addition to a photolithography and electroplating-assisted method, we present an alignment-free, elegant microcapillary force-based process for scalable fabrication of embedded electrodes. The presented transducers have a high potential for application as energy-autonomous sensors for condition monitoring, robotics and wearables.