Title : Europium-doped CH3 NH3 Pb1 xEux I3 for perovskite based solar cell application

Abstract:

The doping process, the controlled insertion of impurities into an extremely pure crystal, represents a strategic approach to improve optical and electrical properties of a device. Hybrid perovskite based solar cells have achieved high efficiency on photovoltaic applications tuning the perovskite composition by variation of the chemical composition or by doping. Inspired by the improvements of optical properties of certain materials by doping with Eu2+ europium could constitute a potential candidate to completely replace lead in order to reduce the defects formation and therefore to improve the stability of the hybrid perovskite solar cells. The choice is based also on their comparable ion radii (Eu2+, 117 pm and Pb2+, 119 pm), which according to the Goldschmidt factor, should induce the formation of a perovskite structure. Perovskite films were fabricated by spin coating in ambient atmosphere.. The crystallinity, morphology, optical absorption and photoluminescence properties, of CH3 NH3 Pb1-xEux I3 (x=0, 0.01; 0.03 and 0.05) are studied. The X-ray diffraction data indicate that the presence of Eu in small concentrations induces the formation of a perovskite crystalline structure. AFM images reveal an increase in roughness with the increase in Eu content. This points to the formation of a crystalline structure on the vertical direction rather that a complete surface coverage. 1% Eu content is the optimum addition for perovskite composition ensuring better crystallization as well as complete surface coverage. This work reveals Eu as a promising candidate to improve the stability in perovskite solar cells.

Biography:

Mihaela Florea received her Bachelor’s degree in Chemistry from the University of Bucharest in 1997 and from the same university she received the Master degree in 1999. The PhD was done under the supervision of Professor Paul Grange in the field of Catalysis at the Universite Catolique de Louvain la Neuve, Belgium and she graduated in 2003 with Suma Cum Laude. In February 2004, she joined the group of Catalysis at the Faculty of Chemistry, University of Bucharest where she began her research on heterogenous catalysis, especially on catalytic selective oxidation. From 2018 she is Senior Researcher at the National Institute of Materials Physics. Her current research focuses on the synthesis and characterization of sustainable catalytic materials for selective oxidation and energy applications. She is the author of >75 publications in the field of heterogeneous catalysis and green chemistry, with a Hirsh factor of 19.