SENSATE team attended 12th European Kesterite Workshop at Copenhagen.

From 9 to 11 February 2022, the SENSATE team took part in the 12th European Kesterite Workshop at Copenhagen.

The theme of this event is the Kesterite as well as other emerging, Earth-abundant inorganic thin-film solar cells. These compounds have the potential to meet the cost, efficiency, and sustainability requirements for future solar energy deployment.

The European Kesterite Workshop is aimed to bring together researchers from all over the world who work on Kesterite solar cells and other emerging thin-film photovoltaic technologies. Since 2009, the event has provided a forum to stimulate discussion on current issues to improve understanding of the kesterite devices and their relatives.

You can visit the 12th European Kesterite Workshop web page here.

Ivan Caño presentation was about developing new (Sb1-xBix)2Se3 thin films as an alternative to Sb2Se3 to explore narrow-bandgap applications, successfully tuning the bandgap in the range of 0.9 to 1.3 eV, demonstrating efficiencies between 3-5% for 0.01<x≤0.10. This is an innovative study, since it demonstrates that the chalcogenide system, constituted by abundant and low toxicity elements, allows to develop devices with tuneable optical properties, opening the door to multiple applications (including tandem devices). During the presentation, a comprehensive study on the evolution of optoelectronic parameters and compositional-structural properties was presented, demonstrating (Sb1-xBix)2Se3 single phase formation with preferred crystalline orientation, which improves carrier transport. On the other hand, its main limitations were analysed in detail by simulations and theoretical experiments, showing that by increasing the Bi content, the material becomes increasingly limited by bulk recombination, thus indicating a possible way to improve its performance in the future. Finally, an interrupted growth synthesis process was performed to determine the formation mechanism of the solid solution, pointing the way to improve control in the synthesis process.

Maykel Jimenez presentation attempts to give a theoretical and experimental point of view to the interfaces of antimony selenide in substrate configuration. To do so, they propose a thermodynamic model based on the reactions that they consider may be taking place, proving that from this point of view both are unstable. To prove this, they deposit ultrathin layers of Mo and CdS on the absorber (in this case they work with absorbers rich and poor in Selenium) and subject these samples to different agents such as light, time and the presence or absence of air. These samples are characterised using different advanced techniques such as Raman, XPS, XRD, XRF… And differences between the different conditions are observed. An experimental step prior to buffer deposition (CdS) is also proposed to avoid intermixing between the absorber and the buffer, as well as possible sulphur or selenium migrations.

Axel Gon Medaille poster presentation intents was to give numerical routes to passivate interfacial defects between CdS and Sb2Se3 by using the device simulation software SCAPS-1D.  First, a baseline device was defined according to in-house and literature processes. Then, 2 routes were developed: the first route was the implementation of an ultrathin layer of TiO2 between the absorber (Sb2Se3) and buffer (CdS) layer while the second consisted of the surface sulfurization of Sb2Se3 in order to passivate interfacial defects. Through this poster, insights were given regarding the evolution of optoelectronics parameters (Voc, FF, Eff., Jsc) according to the thickness of TiO2 layer for the first route and the thickness of the sulfur gradient as well as its content at the forefront of the Sb2Se3 layer in the case of the second route.