Coherent Excitonic Coupling in an Asymmetric Double InGaAs Quantum Well Arises from Many-Body Effects

We study an asymmetric double InGaAs quantum well using optical two-dimensional coherent spectroscopy. The collection of zero-quantum, one-quantum, and two-quantum two-dimensional spectra provides a unique and comprehensive picture of the double well coherent optical response. Coherent and incoherent contributions to the coupling between the two quantum well excitons are clearly separated. An excellent agreement with density matrix calculations reveals that coherent interwell coupling originates from many-body interactions

Dynamics of dark-soliton formation in a polariton quantum fluid

International audiencePolariton fluids have revealed huge potentialities in order to investigate the properties of bosonic fluids at the quantum scale. Among those properties, the opportunity to create dark as well as bright solitons has been demonstrated recently. In the present experiments, we image the formation dynamics of oblique dark solitons. They nucleate in the wake of an engineered attractive potential that perturbs the polariton quantum fluid. Thanks to time and phase measurements, we assess quantitatively the formation process. The formation velocity is observed to increase with increasing distance between the flow injection point and the obstacle which modulates the density distribution of the polariton fluid. We propose an explanation in terms of the increased resistance to the flow and of the conditions for the convective instability of dark solitons. By using an iterative solution of the generalized Gross-Pitaevskii equation, we are able to reproduce qualitatively our experimental results

Experimental Characterization of Micro-Optics for Integrated Tracking Included in HIPERION micro-CPV Modules

Concentrator photovoltaic (CPV) technology, because of the extremely high efficiencies achieved by CPV systems, is nowadays widespread all over the world. Recently, the strong development in the methods and processes used to manufacture both solar cells and optical systems for CPV opened the door to the new frontier of the micro-CPV, that are systems that employs solar cell with a surface aperture smaller than 1 mm2 [1]. The reduction in size of the solar cell implies the proportional shrinking of all the other components, which in turn made possible the implementation of novel features such as the integrated tracking. This technology has been conceived to avoid the use of the external tracking system. Hence, the primary optical element (POE) is designed in order to maintain the shape of the light spot also when sunlight impinges the lens with high incident angles (i.e. ±60º). Obviously, the spot position with respect to the lens varies requiring that the solar cells inside the module follow the spot (see figure 1a). Nowadays, several possible architectures for integrated tracking are being investigated around the world. However, the closest to industrialization is the concept developed by the Swiss company Insolight SA which is currently being developed within the framework of the European project HIPERION (https://hiperion-project.eu/) [2]. Along the project, the modules continuously evolved from the first generation (called GEN0 and developed before the beginning of the project) to the current configuration (GEN2) implementing a series of overall improvement based on the experience learned along the technology development. This work is mainly focused on the difference between GEN1 and GEN2, where the optical design drastically changed

On the Effect of Misalignment Distributions on the I-V Curve of Micro-CPV Modules

Hybrid micro concentrator photovoltaic (CPV) modules that combine conventional and concentrator PV technologies have demonstrated higher efficiency and less installation complexity compared to PV and CPV modules, respectively [2]. Higher efficiency is achieved as the diffuse light is harvested by the conventional PV cells while the direct light is concentrated into highly efficient multijunction solar cells. Higher installation simplicity is reached through module elements downsizing and integrated tracking [4]. The integrated tracking is an embedded system that translates the receivers backplane a few millimeters with respect to the lenses (thanks to the elements’ reduced sizes) for obtaining an on-axis condition as the light angle of incidence varies, allowing installing these fixed modules on rooftops instead of mounting them onto a tracker. However, the high efficiency and excellent performance of CPV modules depend on precise alignment between the lenses and receivers. Misalignments between these elements can significantly reduce the cells current generation [5]. The mounting process has a strong impact on the alignment: the high number of involved lensreceiver units, small mounting tolerances, and difficulties in the integrated tracking positioning can lead to misplacements between lenses and receivers. The distribution of misaligned lens-receiver units impacts the current-voltage (IV) module performance. The severeness of this effect depends on the cells’ interconnection (series/parallel) and bypass diodes location; although in conventional modules each cell has a bypass diode, micro-CPV modules use a single bypass diode for a cells’ string. There are methods to characterize misalignments between the lens-receiver units in a micro-CPV module that can be implementable into production lines, but they are time and resource consuming. Since the misalignments affect the IV curves, a characterization method that is based on IV data and that does not require additional measurements can be highly valued if information about the misalignments can be extracted from its evaluation. In this study, we investigate the relationship between misalignments and the module electrical performance using simulations that reproduce IV curves resulting from given misalignment distributions. We expect that in the future this method, together with machine learning, will serve as a powerful quality control too

High efficiency roof-top solar: progress and pilot installation in the HIPERION project

The Swiss start-up Insolight together with the Hiperion consortium of partners are developing a state of the art static micro-CPV module within the Hiperion project. The Insolight/Hiperion panel applies three different technologies, previously seen only in laboratory prototypes, to a full-size solar device: microscale concentrator photovoltaics, planar micro-tracking, and diffuse capture. The consortium, which includes research centers, industrial leaders, solar installers, and PV manufacturers, will finish a pilot-scale manufacturing facility as well as multiple pilot installations by the end of 2023. The Solar Energy Institute at Madrid Technical University (IES-UPM), along with the Fraunhofer Institute for Solar Energy (ISE) and the PV-center at the Swiss Center for Electronics and Microtechnology (CSEM) are charged with characterizing new module designs developed within the program, as well as creating new measurement methods, standards, and equipment adapted for the specifics of this new technology. Here we present the results of indoor and outdoor measurement of modules of the first batch of “Gen2” modules, the final design to be produced on the Hiperion pilot line, as well as a full year’s worth of field data at two pilot installations installed at IES-UPM and Fraunhofer ISE

Progress and Demonstration of Micro-CPV Module with Integrated Planar Tracking and Diffuse Light Collection

Several technologies have been identified that could produce a new type of high-performance solar product optimized for space-constrained applications: micro-CPV, planar microtracking, and diffuse capture. The Swiss start-up Insolight and the Hiperion consortium are bringing such a device to the industrial level. In this work we share the latest results for full-scale modules, discuss improvements to the design and resulting performance gains, and will report the results from pilot installations in Madrid and Freiburg

Performance of Hybrid Micro-Concentrator Module with Integrated Planar Tracking and Diffuse Light Collection

The Swiss start-up Insolight aims to be the first company to commercialize a high-efficiency III-V based low profile micro-CPV product that uses planar micro-tracking to eliminate the need for a tilting solar tracker, allowing rooftop mounting using typical flat-plate hardware, as well diffuse light capture using low cost Si solar cells which cover the area of the back plane not taken up by III-V solar cells. The IES-UPM has made an initial performance evaluation of a 0.1m2 prototype. We show that the integrated planar tracking can reach 55° AOI, show CSTC efficiency near to 30% for III-V output, and demonstrate the diffuse capture and planar tracking capability in a multi-week test campaign at our test site in Madrid

Performance of Hybrid Micro-Concentrator Module with Integrated Planar Tracking and Diffuse Light Collection

The Swiss start-up Insolight aims to be the first company to commercialize a high-efficiency III-V based low profile micro-CPV product that uses planar micro-tracking to eliminate the need for a tilting solar tracker, allowing rooftop mounting using typical flat-plate hardware, as well diffuse light capture using low cost Si solar cells which cover the area of the back plane not taken up by III-V solar cells. The IES-UPM has made an initial performance evaluation of a 0.1m2 prototype. We show that the integrated planar tracking can reach 55° AOI, show CSTC efficiency near to 30% for III-V output, and demonstrate the diffuse capture and planar tracking capability in a multi-week test campaign at our test site in Madrid

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

non present