A novel cellulose-based bio-battery made of electrospun fibers activated by biological fluids has been developed. This work reports a new concept for a fully organic bio-battery that takes advantage of the high surface to volume ratio achieved by an electrospun matrix composed of sub-micrometric fibers that acts simultaneously as the separator and the support of the electrodes. Polymer composites of polypyrrole (PPy) and polyaniline (PANI) with cellulose acetate (CA) electrospun matrix were produced by in situ chemical oxidation of pyrrole and aniline on the CA fibers. The structure (CA/PPy|CA|CA/PANI) generated a power density of 1.7 mW g−1 in the presence of simulated biological fluids, which is a new and significant contribution to the domain of medical batteries and fully organic devices for biomedical applications.

The influence of post-deposition thermal annealing on the thermoelectric properties of n-and p-type nanocrystalline hydrogenated silicon thin films, deposited by plasma enhanced chemical vapour deposition, was studied in this work. The Power Factor of p-type films was improved from 7× 10− 5 to 4× 10− 4 W/(mK 2) as the annealing temperature, under vacuum, increased up to 400° C while for n-type films it has a minor influence. Optimized Seebeck coefficient values of 460 μV/K and− 320 μV/K were achieved for p-and n-type films, respectively, with crystalline size in the range of 10 nm, leading to remarkable low thermal conductivity values (< 10 Wm− 1. K− 1) at room temperature.

The main objective of TransFlexTeg is to develop an innovative large area distributed sensor network integrating transparent thin film thermoelectric devices and sensors for multifunctional smart windows and flexible high impact volume applications. Different breakthrough concepts will be developed: 1) large area high performance transparent thermoelectric thin films deposited on flexible substrates for thermal energy harvesting; 2) low cost high throughput thin film thermal sensors for thermal mapping and gesture sensing; 3) flexible smart windows and walls with energy harvesting, environmental sensing and wireless communication functionalities. This technology aims to demonstrate the functionalities of a smart window able to measure air quality and environmental parameters such as temperature, sun radiation and humidity. The data is automatically collected and can be utilized for controlling heating, cooling and ventilation systems of indoors. Active radio interface enables long range communication and long term data collection with WiFi or a similar base station. The proposed concept of smart windows replaces several conventional sensors with a distributed sensor network that is integrated invisibly into windows. In addition to the power generated from the thermal energy harvesting, the thermoelectric elements (TE) are also used as temperature sensors that, while being distributed over large area, enable thermal mapping of the area instead of just one or a few values measured from particular points. This smart window can be produced on glass. The active layer itself can be flexible glass layer or polymer sheet, which will significantly broaden the field of applications and improve business opportunities. Both can be manufactured in batch, or in Roll to Roll Atomic Layer Deposition (R2R ALD) process. High environmental impact is expected with savings of more than 25% of the electrical usage of residential homes and office buildings.

The search for materials with suitable thermoelectric properties that are environmentally friendly and abundant led us to investigate p- and n-type hydrogenated nanocrystalline silicon (nc-Si:H) thin films, produced by plasma-enhanced chemical vapor deposition. The Seebeck coefficient and power factor were measured at room temperature showing optimized values of 512 µV K−1 and 3.6 × 10−5 W m−1 K−2, for p-type, and −188 µV K−1 and 2.2 × 10−4 W m−1 K−2, for n-type thin films. The thermoelectric output power of one nc-Si:H pair of both n- and p-type materials is ~91 µW per material cm3, for a thermal gradient of 8 K. The output voltage and current values show a linear dependence with the number of pairs interconnected in series and/or parallel and show good integration performance.