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Inverted polymer solar cells based on P3HT/PCBM bulk heterojunction were prepared on flexible polyethylene naphthalate (PEN) substrate. The effect of annealing of the PEN/ITO/ZnO multilayer and ZnO/P3HT:PCBM on the structural, morphological, photophysical and photovoltaic properties was investigated and scrutinized directly on the OPV devices using atom probe tomography (APT), scanning electron microscopy (SEM) and microfocus X-ray techniques. We carried out a 3D reconstruction of the interfaces of the multilayer containing PEN/ITO, ZnO/ITO and P3HT:PCBM/ZnO to address the interface micro-structure and its influence on the morphology of the photoactive film. The analyses show that the morphology of the interfaces is affected by the structure of each layer of the BHJ devices causing orientation of P3HT crystals with PCBM aggregates and ZnO, which in turn leads to a significant change of the charge transport across each layer and therefore photovoltaic performances.

Bit Patterned Media (BPM) for magnetic recording provide a route to densities $>1 Tb/in^2$ and circumvents many of the challenges associated with conventional granular media technology. Instead of recording a bit on an ensemble of random grains, BPM uses an array of lithographically defined isolated magnetic islands, each of which stores one bit. Fabrication of BPM is viewed as the greatest challenge for its commercialization. In this article we describe a BPM fabrication method which combines e-beam lithography, directed self-assembly of block copolymers, self-aligned double patterning, nanoimprint lithography, and ion milling to generate BPM based on CoCrPt alloys. This combination of fabrication technologies achieves feature sizes of $, 44 pages

This paper reports the design, fabrication and control of arrayed microelectromechanical systems (MEMS)-based actuators for distributed micromanipulation by generation and control of an air-flow force field. The authors present an original design of pneumatic microactuator, improving reliability and durability of a distributed planar micromanipulator described in the previous study. The fabrication process is based on silicon-on-insulator (SOI) wafer and HF (hydroflouric acid) vapor release, which also significantly increases the production yield of the 560 microactuator array device of 35times35 mm2. Minimization of the electrostatic actuation pull-in voltage through suspension shaping fabrication was also studied, and successfully validated for electrical efficiency improvement. A distributed control method to achieve good conveyance performance and reduce motion control instability was investigated. An emulation approach was chosen to validate a decentralized control strategy on the distributed active surface in order to conduct a proof-of-concept of a future smart structure, integrating sensors, intelligence, and microactuators. Thus, a centralized/decentralized control flow, inspired by autonomous mobile robot principles, was applied. It was modeled and implemented using C-programming language. Experimental and characterization results validate the control method for feedback micromanipulation with good velocity and load capacity performance

A technique for the self-alignment of components is applied to the assembly of a passive micro-valve which is to be used for safety purposes in a miniature fuel cell. The technique uses the capillary forces originating in the interactions of HMDS (Hexadimethyldisilazane) and the faces of the components to achieve their passive alignment. HMDS is chosen because it is a volatile, low surface tension and inert liquid. The originality of this method is that the liquid area is defined by the edges of the components. Compared to a traditional pick-and-place technique, it leads to a leakage rate more than five times smaller.

International audience; Distributed-air-jet MEMS-based systems have been proposed to manipulate small parts with high velocities and without any friction problems. The control of such distributed systems is very challenging and usual approaches for contact arrayed system don't produce satisfactory results. In this paper, we investigate reinforcement learning control approaches in order to position and convey an object. Reinforcement learning is a popular approach to find controllers that are tailored exactly to the system without any prior model. We show how to apply reinforcement learning in a decentralized perspective and in order to address the global-local trade-off. The simulation results demonstrate that the reinforcement learning method is a promising way to design control laws for such distributed systems.

International audience; In this paper, an efficient and reliable neural active power filter (APF) to estimate and compensate for harmonic distortions from an AC line is proposed. The proposed filter is completely based on Adaline neural networks which are organized in different independent blocks. We introduce a neural method based on Adalines for the online extraction of the voltage components to recover a balanced and equilibrated voltage system, and three different methods for harmonic filtering. These three methods efficiently separate the fundamental harmonic from the distortion harmonics of the measured currents. According to either the Instantaneous Power Theory or to the Fourier series analysis of the currents, each of these methods are based on a specific decomposition. The original decomposition of the currents or of the powers then allows defining the architecture and the inputs of Adaline neural networks. Different learning schemes are then used to control the inverter to inject elaborated reference currents in the power system. Results obtained by simulation and their real-time validation in experiments are presented to compare the compensation methods. By their learning capabilities, artificial neural networks are able to take into account time-varying parameters, and thus appreciably improve the performance of traditional compensating methods. The effectiveness of the algorithms is demonstrated in their application to harmonics compensation in power systems.

We propose a microconveyor based on silicon microelectromechanical systems (MEMS) technology and demonstrate successful operation of the microconveyor. Microactuators work as air nozzles, which generate directed air flow by changing the pathways of compressed nitrogen gas. One-dimensional conveyance of an object 2.1mm × 4.1mm × 200μm weighing approximately 4mg is demonstrated with a directed air flow of 17kPa. Using a two-dimensional conveyor, we levitate and move an object 3mm × 3mm × 100μm weighing approximately 2mg using a continuous air flow. Conveyance toward the force equilibrium point was achieved with a regularly pulsed air flow. We are now studying full control of two-dimensional conveyance. We also propose control by actuating air nozzles to change the direction of air flow and move the equilibrium point to transfer the object to the desired point.

Block copolymer lithography, an alternative lithographic technique by which self-assembled patterns made from block copolymer thin films are used as lithographic masks, has achieved a high enough level of maturity to be considered for nanofabrication in magnetic recording bit patterned media and in some applications in the semiconductor industry. As the demand for lithographic dimensions squeezes into the single-digit nm scale, pairing block copolymer materials that segregate at these dimensions with adequate pattern transfer techniques is increasingly difficult. For example, PS-b-PMMA, the most mature block copolymer system can only form line/space patterns with pattern transfer above 10 nm. Other promising materials like P2VP-PS-P2VP triblocks, however, lack sufficient etch contrast for reactive ion etching. Here, we present a nanofabrication strategy that integrates atomic layer deposition, ALD, with block copolymer lithography to enable fabrication of sub-10nm features for high density magnetic storage. The selective, cyclic and self-terminating nature of the materials synthesis within ALD reactors provides powerful nanofabrication tools. In particular, two of these tools stand out as enablers for high density patterning: First, the chemical selectivity of the organometallic precursors has facilitated selective synthesis inside porous polymeric materials. Second, the conformality afforded by the self-terminating nature of the ALD reactions has proven to be ideally suited for feature doubling in self-aligned double patterning, SADP. Integrating these powerful tools with block copolymer lithography opens new possibilities in two fronts: On the one hand, it is possible to generate hybrid nanocomposites with nanometer-scale resolution and high etching contrast. This is particularly useful for high resolution block copolymer materials for which no natural etch contrast exists such as P2VP-PS-P2VP triblocks. On the other hand, it is possible to use the already sub-lithographic features obtained by standard PS-b-PMMA block copolymer lithography as the starting point for an additional density multiplication using spacer lines grown by ALD for SADP. Be it for selective infiltration synthesis in block copolymer patterns or for the precise conformal growth in nanostructures made from block copolymers, ALD is likely to emerge as an ideal complimentary technique to block copolymer self assembly to enable sub-10nm lithography.