title: An inorganic-organic hybrid crystal with a two-step dielectric response and thermochromic luminescence.
abstract: An iodoplumbate-based hybrid crystal [C2-Apy][PbI3] (1) (C2-Apy+= 1-ethyl-4-aminopyridinium) was synthesized and characterized structurally. Single crystal X-ray diffraction revealed that 1 crystallizes in the orthorhombic system with the space group Pnma at 150 K. Inorganic components form straight and face-sharing octahedral [PbI3]∞chains and organic components form C2-Apy+cations that are incorporated into the space between the inorganic chains. A temperature-dependent single crystal structure indicates that there exists an order-disorder transition of the cation. The dynamic motion of the cation strongly influences the dielectric and emission features of 1. 1 shows a two-step dielectric response. The first step dielectric response at a low frequency is caused by direct current conduction and electrode polarization which have been proved by impedance spectra. The second dielectric response at a high frequency (10 kHz to 10 MHz) is related to the order-disorder transition of the alkyl chain and the dynamic motion of pyridyl rings. In addition, 1 shows multi-band emission, and different emission bands show different trends with the temperature change, which makes 1 exhibit thermochromic luminescence properties.
authors.affiliation: Key laboratory of Advanced Functional Materials of Nanjing, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China. duanhaibao4660@163.com and Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
authors.forename: Hai-Bao
authors.identifier: http://orcid.org/0000-0001-8706-9278
authors.initials: HB
authors.lastname: Duan
authors.affiliation: Key laboratory of Advanced Functional Materials of Nanjing, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China. duanhaibao4660@163.com.
authors.forename: Shan-Shan
authors.initials: SS
authors.lastname: Yu
authors.affiliation: Key laboratory of Advanced Functional Materials of Nanjing, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China. duanhaibao4660@163.com.
authors.forename: Shao-Xian
authors.initials: SX
authors.lastname: Liu
authors.affiliation: Key laboratory of Advanced Functional Materials of Nanjing, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China. duanhaibao4660@163.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang