He received his PhD also at the same University in 2008. He also spent one year in Forschungszentrum Julich (Peter Grünberg Institute, Germany) during his PhD and later stayed at the University Duisburg-Essen, Germany as a post-doc. His research interests are graphene-based and other 2D materials and their chemical modifications. He has published over 270 articles, which received over 5000 citations (h-index of 35).