Bright blue emissions on UV-excitation of LaBO3 (B=In, Ga, Al) perovskite structured phosphors for commercial solid-state lighting applications

Bright blue photoluminescence (PL) was obtained from Bi3+-activated LaBO3 (B = In, Ga, Al) perovskite nanophosphors. A cost-effective and low-temperature chemical route was employed for preparing Bi3+ doped LaBO3 (B=In, Ga, Al) which were then annealed at 1000 °C. The phase formation, morphological studies and luminescent properties of the as-prepared samples were performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence and optical absorption spectroscopy. Comparison of emission intensities, lifetime studies, energy band gaps and color purity of all samples (pure and Bi3+ doped) were investigated for promising applications in UV light-emitting diodes, variable frequency drive (VFD), field emission display (FED), and other photoelectric fields

Sensitive spin detection using an on-chip SQUID-waveguide resonator

International audiencePrecise detection of spin resonance is of paramount importance to achieve coherent spin control in quantum computing. We present a novel setup for spin resonance measurements, which uses a dc-SQUID flux detector coupled to an antenna from a coplanar waveguide. The SQUID and the waveguide are fabricated from 20~nm Nb thin film, allowing high magnetic field operation with the field applied parallel to the chip. We observe a resonance signal between the first and third excited states of Gd spins $S=7/2$ in a CaWO$_4$ crystal, relevant for state control in multi-level systems

Fuel Cells and Batteries In Silico Experimentation Through Integrative Multiscale Modeling

International audienceDevices for electrochemical energy conversion and storage exist at different levels of development, from the early stages of R&D to mature and deployed technologies. Thanks to the very significant progresses achieved in the field of computational science over the past few decades, multiscale modeling and numerical simulation are emerging as powerful tools for in silico studies of mechanisms and processes in these devices. These innovative approaches allow linking the chemical/microstructural properties of materials and components with their macroscopic efficiency. In combination with dedicated experiments, they can potentially provide tremendous progress in designing and optimizing the next-generation electrochemical cells. This chapter provides a comprehensive overview of the theory and practical aspects of integrative multiscale modeling tools within the context of fuel cells and rechargeable batteries. Additionally, the chapter discusses technical dreams and methodological challenges that computational science is facing today in order to help developing efficient, durable, and low-cost electrochemical energy devices but also to trigger major technological breakthroughs