Solcore: A multi-scale, python-based library for modelling solar cells and semiconductor materials

Computational models can provide significant insight into the operation mechanisms and deficiencies of photovoltaic solar cells. Solcore is a modular set of computational tools, written in Python 3, for the design and simulation of photovoltaic solar cells. Calculations can be performed on ideal, thermodynamic limiting behaviour, through to fitting experimentally accessible parameters such as dark and light IV curves and luminescence. Uniquely, it combines a complete semiconductor solver capable of modelling the optical and electrical properties of a wide range of solar cells, from quantum well devices to multi-junction solar cells. The model is a multi-scale simulation accounting for nanoscale phenomena such as the quantum confinement effects of semiconductor nanostructures, to micron level propagation of light through to the overall performance of solar arrays, including the modelling of the spectral irradiance based on atmospheric conditions. In this article we summarize the capabilities in addition to providing the physical insight and mathematical formulation behind the software with the purpose of serving as both a research and teaching tool.Comment: 25 pages, 18 figures, Journal of Computational Electronics (2018

Volume exclusion effects in perovskite charge transport modeling

Due to their flexible material properties, perovskite materials are a promising candidate for many semiconductor devices such as lasers, memristors, LEDs and solar cells. For example, perovskite-based solar cells have recently become one of the fastest growing photovoltaic technologies. Unfortunately, perovskite devices are far from commercialization due to challenges such as fast degradation. Mathematical models can be used as tools to explain the behavior of such devices, for example drift-diffusion equations portray the ionic and electric motion in perovskites. In this work, we take volume exclusion effects on ion migration within a perovskite crystal lattice into account. This results in the formulation of two different ionic current densities for such a drift-diffusion model – treating either the mobility or the diffusivity as density-dependent while the other quantity remains constant. The influence of incorporating each current density description into a model for a typical perovskite solar cell configuration is investigated numerically, through simulations performed using two different open source tools

e-Bug Games for Children: Teaching Hygiene and Prudent Antibiotics Use using Web Games

Technology enhanced education has been recently established as a new approach for all stages of education. However, among these new IT media it is computer games playing the central role in delivering education in particular to children and teenagers, however, real world sound evaluation is often given little attention. The EU funded e-Bug project developed web games aimed at children to teach basic principles of pru- dent antibiotics use, hand and respiratory hygiene and aims to reinforces an awareness of microbes, hand and respiratory hygiene among junior and senior school children in 10 countries in Europe. An educational pack implemented in schools across Europe is complemented by Internet web games for two age groups teaching a set of learning objectives (LOs) using a fast and interactive platform game design for junior children and investigate detective games based on PBL principles for senior children. In this paper, we present the design of e-Bug junior and senior games and evaluation results

CeRC Story-Game Engine: An open source technology to power story based investigation games

Playing computer games is widely popular among children and teenagers as an entertainment activity; however computer games can also be easily transformed into tools for education. City University London’s City eHealth Research Centre (CeRC) - has developed such educational computer games to improve young people’s understanding of the importance of hand and respiratory hygiene and responsible antibiotic use; and to teach school syllabus concepts such as microbes, the spread and prevention of infection, antibiotic use and antibiotic resistance. We have developed a game platform as an open-source framework to promote game development for education and entertainment. The platform enables the efficient development of new games with new learning objectives along with the ability to support translation into any language. For example, the current CeRC games have been translated into 11 European languages (English, BelgianFrench, Flemish, Czech, Danish, French, Greek, Italian, Polish, Portuguese, and Spanish). The existing CeRC games are targeted towards school children; however, we investigate the usability of utilizing such games for adult education as well as examining the effectiveness of these games to convey messages to particular academic, industrial (or otherwise) communities

Reflexive obstacle avoidance for kinematically-redundant manipulators

Dexterous telerobots incorporating 17 or more degrees of freedom operating under coordinated, sensor-driven computer control will play important roles in future space operations. They will also be used on Earth in assignments like fire fighting, construction and battlefield support. A real time, reflexive obstacle avoidance system, seen as a functional requirement for such massively redundant manipulators, was developed using arm-mounted proximity sensors to control manipulator pose. The project involved a review and analysis of alternative proximity sensor technologies for space applications, the development of a general-purpose algorithm for synthesizing sensor inputs, and the implementation of a prototypical system for demonstration and testing. A 7 degree of freedom Robotics Research K-2107HR manipulator was outfitted with ultrasonic proximity sensors as a testbed, and Robotics Research's standard redundant motion control algorithm was modified such that an object detected by sensor arrays located at the elbow effectively applies a force to the manipulator elbow, normal to the axis. The arm is repelled by objects detected by the sensors, causing the robot to steer around objects in the workspace automatically while continuing to move its tool along the commanded path without interruption. The mathematical approach formulated for synthesizing sensor inputs can be employed for redundant robots of any kinematic configuration

Characterization of frequency drift of sampled-grating DBR laser module under direct modulation

The authors demonstrate the drift in frequency of a static sampled-grating distributed Bragg reflector (SG DBR) laser module when it is subjected to direct modulation. The magnitude of drift and its settling time is characterized as a function of the index of modulation. Results show that when the directly modulated SG DBR is optically filtered, as in a dense wavelength- division- multiplexed system, a power penalty of 6.7 dB is incurred in comparison to the unfiltered case

Conditions for one-dimensional supersonic flow of quantum gases

One can use transsonic Bose-Einstein condensates of alkali atoms to establish the laboratory analog of the event horizon and to measure the acoustic version of Hawking radiation. We determine the conditions for supersonic flow and the Hawking temperature for realistic condensates on waveguides where an external potential plays the role of a supersonic nozzle. The transition to supersonic speed occurs at the potential maximum and the Hawking temperature is entirely determined by the curvature of the potential