Search results for "Kite"

Effects of Frequency Dependence of the External Quantum Efficiency of Perovskite Solar Cells

2018

Perovskite solar cells are known to show very long response time scales, on the order of milliseconds to seconds. This generates considerable doubt over the validity of the measured external quantum efficiency (EQE) and consequently the estimation of the short-circuit current density. We observe a variation as high as 10% in the values of the EQE of perovskite solar cells for different optical chopper frequencies between 10 and 500 Hz, indicating a need to establish well-defined protocols of EQE measurement. We also corroborate these values and obtain new insights regarding the working mechanisms of perovskite solar cells from intensity-modulated photocurrent spectroscopy measurements, iden…

Integrated Optical Amplifier-Photodetector on a Wearable Nanocellulose Substrate

2018

Flexible optoelectronics has emerged as an outstanding platform to pave the road toward vanguard technology advancements. As compared to conventional rigid substrates, a flexible technology enables mechanical deformation while maintaining stable performance. The advantages include not only the development to novel applications, but also the implementation of a wearable technology directly in contact with a curved surface. Here the monolithic integration of a perovskite‐based optical waveguide amplifier together with a photodetector on a nanocellulose substrate is shown to demonstrate the feasibility of a stretchable signal manipulation and receptor system fabricated on a biodegradable mater…

ITO top-electrodes via industrial-scale PLD for efficient buffer-layer-free semitransparent perovskite solar cells

2022

The deposition of transparent conductive oxides (TCO) usually employs harsh conditions that are frequently harmful to soft/organic underlayers. Herein, successful use of an industrial pulsed laser deposition (PLD) tool to directly deposit indium tin oxide (ITO) films on semitransparent vacuum-deposited perovskite solar cells without damage to the device stack is demonstrated. The morphological, electronic, and optical properties of the PLD deposited ITO films are optimized. A direct relation between the PLD chamber pressure and the solar cell performance is obtained. The semitransparent perovskite solar cells prepared exclusively by vacuum-assisted techniques had fill factors of 78% and exc…

An overview of the music therapy professional recognition in the EU

2016

This article documents the development of the professional recognition of music therapy in the EU. First, a brief history of the origins of modern music therapy in Europe is presented, followed by more detailed analysis of the establishment of training courses and professional associations across Europe. Second, the stages in the professionalization process according to Ridder, Lerner and Suvini (2015) are discussed. Third, the importance of the European Music Therapy Confederation in promoting music therapy recognition in the EU is highlighted.

On the aestheticization of technologized bodies : a portrait of a cyborg(ed) form of agency

2017

Discussions revolving around cyborgs seldom include aesthetics, let alone propose aesthetics as an inextricable part of the phenomenon of the cyborg. Rather, the term “cyborg”, a contraction of “cybernetic organism”, evokes a figure of the (hu)man- machine. In the field of social and political sciences, the cyborg is designated a human-machine hybrid, a metaphor of humans becoming machinelike, or a portrait of (political) agency in an era of high technology. These approaches promote a figure of technologized bodies, that is, the cyborg as a figure of technologically dominated and altered bodies. I will sustain that the cyborg contributes to our understanding of agency in the age of high tec…

Ultralow thermal conductivity in 1D and 2D imidazolium-based lead halide perovskites

2021

Low-dimensional hybrid organic–inorganic metal halide perovskites are rapidly emerging as a fascinating sub-class of the three-dimensional parent structures, thanks to their appealing charge and thermal transport properties, paired to better chemical and thermal stabilities. Extensive investigations of the thermal behavior in these systems are of paramount relevance to understand their optoelectronic and thermoelectric applications. Herein, we present a complete thermophysical characterization of imidazolium lead iodide, (IMI)PbI3, a 1D pseudo-perovskite with chains of face-sharing octahedra, and histammonium lead iodide, (HIST)PbI4, a 2D layered perovskite with corner-sharing octahedra. Up…

Single zircon ages of migmatitic gneisses and granulites in the Obudu Plateau: Timing of granulite-facies metamorphism in southeastern Nigeria

2006

Abstract A single zircon geochronological study of gneisses from the Obudu Plateau of southeastern Nigeria, using the evaporation technique, indicates that zircons recorded several Precambrian high-grade metamorphic events (Eburnean and Pan-African). Igneous and multifaceted metamorphic zircons yielded 207 Pb/ 206 Pb ages of 2062.4 ± 0.4 Ma, 1803.8 ± 0.4 Ma and 574 ± 10 Ma, respectively and confirm for the first time that granulite-facies metamorphism affected the basement of southeastern Nigeria, resulting in the formation of charnockites and granulitic gneisses. The Pan-African high-grade event was coeval with the formation of granulites in Cameroon, Togo and Ghana and resulted from colli…

On the Shape-Selected, Ligand-Free Preparation of Hybrid Perovskite (CH3NH3PbBr3) Microcrystals and Their Suitability as Model-System for Single-Crys…

2021

Hybrid perovskite materials are one of the most promising candidates for optoelectronic applications, e.g., solar cells and LEDs, which can be produced at low cost compared to established materials. Although this field of research has seen a huge upsurge in the past decade, there is a major lack in understanding the underlying processes, such as shape-property relationships and the role of defects. Our aerosol-assisted synthesis pathway offers the possibility to obtain methylammonium lead bromide (MAPbBr3 ) microcrystals from a liquid single source precursor. The differently shaped particles are aligned on several substrates, without using a directing agent or other additives. The obtained …

Arkipäivän arvokkuutta ja inhimillisten mittasuhteiden arkkitehtuuria : Martti Välikankaan rakennukset Mikkelissä 1931-1941

1998

Hybrid DFT calculations of the atomic and electronic structure for ABO3 perovskite (001) surfaces

2005

Abstract We present the results of first-principles calculations on two possible terminations of the (0 0 1) surfaces of SrTiO3, BaTiO3, and PbTiO3 perovskite crystals. Atomic structure and the electronic configurations were calculated for different 2D slabs, both stoichiometric and non-stoichiometric, using hybrid (B3PW) exchange-correlation technique and re-optimized basis sets of atomic (Gaussian) orbitals. Results are compared with previous calculations and available experimental data. The electronic density distribution near the surface and covalency effects are discussed in details for all three perovskites. Both SrTiO3 and BaTiO3 (0 0 1) surfaces demonstrate reduction of the optical …