Regensburg 2022 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Perovskite and Photovoltaics 2

CPP 19.3: Talk

Wednesday, September 7, 2022, 10:15–10:30, H38

Influence of crystallization on the structural and optical properties of lead-free Cs2AgBiBr6 perovskite crystals — •Melina Armer¹, Julian Höcker², Carsten Büchner¹, Sophie Häfele¹, Patrick Dörflinger¹, Maximilian T. Sirtl³, Kristofer Tvingstedt¹, Thomas Bein³, and Vladimir Dyakonov¹ — ¹Experimental Physics VI, Julius Maximilian University of Würzburg, 97074 Würzburg — ²Ludwigs Maximilian University München, 80539 München — ³Ludwigs Maximilian University München, 81377 München

As conventional perovskite solar cells contain lead and therefore suffer from toxicity issues, finding stable lead-free materials for the application in perovskite photovoltaics has become an essential problem to be solved. In this work, lead-free Cs2AgBiBr6 single crystals have been synthesized by slowly evaporating organic solvents and by using the well-known controlled cooling technique. The evaluation of solubility curves showed that slow evaporation enables crystal growth in a wide range of temperatures. We further used the controlled cooling technique as a reference to the slow evaporation method to grow crystals at different temperatures. The quality of the synthesized crystals was characterized by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) measurements. Furthermore, photoluminescence excitation (PLE) and absorption measurements were conducted to investigate the relationship between Urbach energy and the growth method and temperature. As a result, we found that growth temperatures significantly impact the amount of tail-states present in the perovskite crystals.