Switchable Dielectric Two-Dimensional Lead-Free Perovskite with Reversible Thermochromic Response

Abstract

Two-dimensional (2D) organic–inorganic hybrid perovskites (OIHPs) have attracted great interest due to their unique properties for optical, thermal, electric, force, and magnetic applications. However, although some 2D HOIPs with thermochromic properties have been obtained, the issue of toxicity of lead and single-stimulus response impose restrictions on their further applications. To overcome this limitation, we scientifically design and fabricate a novel two-dimensional organic–inorganic hybrid lead-free perovskite [2,5-DCA]2·[CuCl4] (1), which simultaneously possesses excellent reversible chromic/dielectric response under thermal stimulation. Specifically, along with the change in temperature (303–413 K), crystal 1 displays a reversible color change between yellow-green and red-brown with a band gap variation from 2.25 to 2.05 eV. Besides, compared with other thermochromic perovskites, crystal 1 also exhibits a sensitive dielectric transition at a lower phase-transition point (around 369 K) with high fatigue resistance. This study demonstrates a reliable strategy for the fabrication of multiple-stimuli-responsive materials and sheds light on the study of two-dimensional lead-free perovskites in smart windows.

Inversion of Molecular Chirality Associated with Ferroelectric Switching in a High-Temperature Two-Dimensional Perovskite Ferroelectric

“…Moreover, the single crystal of 1 shows the thermochromic property that is similar to the other Cu II Cl complexes. ,,,− As shown in Figure S14, the yellow single crystal at the RT gradually changed to a red-brown color upon heating to 393 K, and the yellow color can be recovered by cooling the sample. The temperature-dependent UV–vis absorption spectra revealed that the absorption band underwent redshifts with the absorption edge moving from 560 nm at 293 K to 605 nm at 393 K, which agrees well with the observed color change of 1 (Figure S15).…”

Halogen engineering of organic–inorganic hybrid perovskites displaying nonlinear optical, fluorescence properties and phase transition

“…The reliable modulation of photoelectric characteristics in phase-transition materials has been demonstrated due to the diversity of organic and inorganic constituents. [1][2][3][4][5][6][7][8][9][10] An important characteristic of phase-transition materials is their stimulus-response properties such as step-like change of dielectric permittivity in the case of switchable dielectrics, [11][12][13][14][15][16][17][18] onset of ferroelectric order in ferroelectrics, [19][20][21][22][23][24][25][26][27][28] appearance of second-harmonic generation (SHG) in second-order nonlinear optical (NLO) materials, 21,24,25,27,29 and appearance of magnetic order in ferromagnets or antiferromagnets. 26,27,30 These materials can be reversibly switched between different states in the transmission or memory of signals or phase states, when exposed to external stimuli such as light, temperature, pressure or magnetic field, thus showing outstanding potential in multiple fields such as data storage, 31 photoelectric switches, sensors, and data communication-and therefore their physical properties have been widely studied.…”

Reversible phase transition and thermochromic response in hybrid copper-based perovskites

“…45 Further, the lead-free perovskite material (2,5-DCA) 2 CuCl 4 (2,5-DCA = 2,5-dichloroamylaminium) reported by our group exhibits a reversible thermochromic/dielectric response under thermal stimulation. 42 Consequently, there is an urgent need to develop lead-free 2D OIHP materials with reversible thermochromic/dielectric responses.…”