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论文类型：期刊论文

发表时间：2014-11-20

发表刊物：JOURNAL OF PHYSICAL CHEMISTRY LETTERS

收录刊物：SCIE、EI

卷号：5

期号：22

页面范围：3958-3963

ISSN号：1948-7185

摘要：We focus here our attention on a particular family of 2D-layered and 3D hybrid perovskite molecular crystals, the mixed perovskites (C6H5-C2H4-NH3)(2)PbZ(4(1-x))Y(4x) and (CH3-NH3)PbZ(3(1-x))Y(3x), 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.