EventDr. Hasan Şahin

Experimental and theoretical investigation of dopant-driven color change in perovskite crystals

In my talk, I’ll present our recent results on Cesium lead perovskites which are suitable materials for various optoelectronic applications due to their exceptionally good optical properties. The e¬ect of Mn doping on the structural and optical properties of cesium lead halide perovskite crystals are investigated from both experimental and theoretical points of view. It is found that adding MnCl during the synthesis not only leads to a Mn-driven structural phase transition from Cs PbBr to CsPbCl but also triggers the Br– to Cl– halide exchange. On the other hand, it is observed that, under UV illumination, the color of Mn-doped crystals changes from orange to blue in approximately 195 h. While the intensity of Mn-originated photoluminescence emission exponentially decays in time, the intensity of CsPbCl -originated emission remains unchanged. In addition, di¬usive motion of Mn ions results in both a growing population of MnO at the surface and transition of the host into a cesium-rich Cs PbCl phase.

Hasan Sahin was born in 1980 in Berlin, Germany. He completed his primary, secondary and high school education in Mersin and received his BS and MS degrees from Department of Physics, Ankara University. He received his PhD from the Bilkent University Institute of Materials Science and Nanotechnology in 2011. Since 2016 he has been working at Department of Photonics in Izmir Institute of Technology. Dr. Sahin’s team is working on theoretical and experimental investigation of electronic, magnetic, quantum transport, phononic and optical properties of materials. Dr. Sahin has been contributed to more than 95 scientic publications (7700 citations and h-index: 34). Sahin was awarded by Marie-Curie scholarship in 2012-2015, BAGEP in 2016, FABED in 2016, TÜBA GEBIP in 2017, METU Parlar Foundation in 2017 and TÜBITAK TESVIK in 2018. Recent projects carried out by Dr. Sahin’s group (CENT | Computational & Experimental NanoTechnology) have focused on the theoretical and experimental investigation of new generation perovskite crystals and ultra-thin heterostructures.