The EUC Colloquium on Mathematics, Computer Science and Engineering was established in November 2011 and is organized by the Department of Computer Science of the European University Cyprus. The purpose of Colloquium is to provide a forum to our colleagues, our current and potentially future collaborators as well as known scientists to meet, present research findings, and discuss developments on a variety of topics spanning all important fields of Computer Science and Engineering. It also aims to provide an environment in which graduate students can gain experience in presenting their work, and benefit from contact with established researchers. The scope of the colloquium includes all aspects of Computer science, including Networks, Software Engineering, Databases, Algorithms, Theoretical Computer Science, Human Computer Interaction, High Performance Computing, and Operational Research, as well as aspects of Mathematics and Engineering.
If you are interested in giving at talk at the Colloquium, please contact the coordinator Dr. Vicky Papadopoulou by filling out the Colloquium Form.
|Title||Spectrally tuned solar cells for improved energy harvesting|
Photovoltaic cells that incorporate several active junctions in electrical series are exhibiting ever higher laboratory efficiencies. However, due to the presence of only two terminals in multi-junction PV cells, Spectral Response (SR) or External Quantum Efficiency (EQE) measurements on these cells present additional challenges compared to single-junction devices. Furthermore, optical interactions between such junctions are more likely to occur due to their series connection.
To this end, EQE measurements at different voltage-light bias conditions have been performed for the development of characterization protocols of multi-junction devices. Moreover, in an attempt to determine the magnitude of coupling current as well as the factors affecting the optical interactions between junctions, excitation and voltage dependent Photoluminescence (PL) measurements of GaInP/GaInAs/Ge have been carried out. The coupling efficiency depends on the shunt resistance of the top junctions as well as on their temperatures. Significant radiative losses from tandem PV cells can lead to underestimation of the cells’ efficiency. For this purpose, combined Electroluminescence (EL) and Photoluminescence (PL) measurements under a high-intensity solar simulator were conducted in order to investigate the presence of radiative losses in a multi-junction cell at different operating conditions of the tandem. Outdoor assessment of tandem devices is required to examine the impact of spectral sensitivity of junctions upon their operating efficiencies. Initial analysis of outdoor measurements has revealed differences between the short-circuit currents and fill factors of the cells that is attributed to their spectral response. A detailed and reliable spectral irradiance dataset is needed to assess how the variations in solar spectrum can affect energy yield. The SMARTS atmospheric radiative transfer model was used to generate long-term irradiance data.
Vasiliki Paraskeva received her undergraduate and Master degree in Physics from the University of Cyprus in 2007 and 2009 respectively. During her Master thesis, she conducted research at the Research Centre of Ultrafast Science in the Department of Physics. She joined the PV Technology Laboratory in 2009 at the Department of Electrical & Computer Engineering as a graduate level researcher (PhD). She is currently working on a project for the study of the impact of spectral response on multi-junction PV cells efficiency. Her research interests include characterization of novel PV cells with a number of methods such as Electroluminescence (EL), Photoluminescence (PL) and External Quantum Efficiency (EQE) as well as testing and monitoring of CPV modules.