Room-Temperature Optical Tunability and Inhomogeneous Broadening in 2D-Layered Organic-Inorganic Perovskite Pseudobinary Alloys.
We focus here our attention on a particular family of 2D-layered and 3D hybrid perovskite molecular crystals, the mixed perovskites (C6H5-C2H4-NH3)2PbZ4(1-x)Y4x and (CH3-NH3)PbZ3(1-x)Y3x, where Z and Y are halogen ions such as I, Br, and Cl. Studying experimentally the disorder-induced effects on the optical properties of the 2D mixed layered materials, we demonstrate that they can be considered as pseudobinary alloys, exactly like Ga1-xAlxAs, Cd1-xHgxTe inorganic semiconductors, or previously reported 3D mixed hybrid perovskite compounds. 2D-layered and 3D hybrid perovskites afford similar continuous optical tunability at room temperature. Our theoretical analysis allows one to describe the influence of alloying on the excitonic properties of 2D-layered perovskite molecular crystals. This model is further refined by considering different Bohr radii for pure compounds. This study confirms that despite a large binding energy of several 100 meV, the 2D excitons present a Wannier character rather than a Frenkel character. The small inhomogeneous broadening previously reported in 3D hybrid compounds at low temperature is similarly consistent with the Wannier character of free excitons.
†Laboratoire Aimé Cotton, Ecole Normale Supérieure de Cachan, CNRS, Université Paris-Sud, Bât 505 Campus d'Orsay, 91405 Orsay, France.
Gaëtan
G
Lanty
†Laboratoire Aimé Cotton, Ecole Normale Supérieure de Cachan, CNRS, Université Paris-Sud, Bât 505 Campus d'Orsay, 91405 Orsay, France.
Khaoula
K
Jemli
†Laboratoire Aimé Cotton, Ecole Normale Supérieure de Cachan, CNRS, Université Paris-Sud, Bât 505 Campus d'Orsay, 91405 Orsay, France.|∥School of Physics and Optoelectronic Engineering, Dalian University of Technology, N° 2 Linggong Road, Ganjingzi District, Dalian City, Liaoning Province, People's Republic of China.
Yi
Y
Wei
‡Institut Pascal, Clermont Université, CNRS and Université Blaise Pascal, 24 Avenue des Landais, 63177 Aubière cedex, France.
Joël
J
Leymarie
§Université Européenne de Bretagne, INSA, FOTON, UMR 6082, 35708 Rennes, France.
Jacky
J
Even
†Laboratoire Aimé Cotton, Ecole Normale Supérieure de Cachan, CNRS, Université Paris-Sud, Bât 505 Campus d'Orsay, 91405 Orsay, France.
Jean-Sébastien
JS
Lauret
†Laboratoire Aimé Cotton, Ecole Normale Supérieure de Cachan, CNRS, Université Paris-Sud, Bât 505 Campus d'Orsay, 91405 Orsay, France.
Emmanuelle
E
Deleporte
exciton; hybrid perovskites; optoelectronics; solar cells