The application of organic electronic materials for the detection of ionizing radiations is very appealing thanks to their mechanical flexibility, low-cost and simple processing in comparison to their inorganic counterpart. In this work we investigate the direct X-ray photoconversion process in organic thin film photoconductors. The devices are realized by drop casting solution-processed bis-(triisopropylsilylethynyl)pentacene (TIPS-pentacene) onto flexible plastic substrates patterned with metal electrodes; they exhibit a strong sensitivity to X-rays despite the low X-ray photon absorption typical of low-Z organic materials. We propose a model, based on the accumulation of photogenerated charges and photoconductive gain, able to describe the magnitude as well as the dynamics of the X-ray-induced photocurrent. This finding allows us to fabricate and test a flexible 2 × 2 pixelated X-ray detector operating at 0.2 V, with gain and sensitivity up to 4.7 × 10⁴ and 77,000 nC mGy⁻¹ cm⁻³, respectively.

In this paper, we propose a novel technological approach for the implementation of large-area flexible artificial skin based on arrays of piezoelectric polymer transducers. Polyvinylidene fluoride (PVDF) transducers are chosen for the high electromechanical transduction frequency bandwidth (up to 1 kHz). A low-cost and scalable technique for extracting PVDF signals is used to directly provide the piezoelectric film with patterned electrodes. If the skin is meant to cover large areas of a robot body, specific requirements have to be fulfilled from the point of view of the overall system and of the technology. Experimental tests on the prototype skin modules demonstrate the feasibility of the proposed approach and reveal the potentiality to build large area flexible skin.

Organic semiconductor materials exhibit a great potential for the realization of large-area solution-processed devices able to directly detect high-energy radiation. However, only few works investigated on the mechanism of ionizing radiation detection in this class of materials, so far. In this work we investigate the physical processes behind X-ray photoconversion employing bis-(triisopropylsilylethynyl)-pentacene thin-films deposited by bar-assisted meniscus shearing. The thin film coating speed and the use of bis-(triisopropylsilylethynyl)-pentacene:polystyrene blends are explored as tools to control and enhance the detection capability of the devices, by tuning the thin-film morphology and the carrier mobility. The so-obtained detectors reach a record sensitivity of 1.3 · 10⁴ µC/Gy·cm², the highest value reported for organic-based direct X-ray detectors and a very low minimum detectable dose rate of 35 µGy/s. Thus, the employment of organic large-area direct detectors for X-ray radiation in real-life applications can be foreseen.