Segmented Highly Reversible Thermochromic Layered Perovskite [(CH2)2(NH3)2]CuCl4 Crystal Coupled with an Inverse Magnetocaloric Effect

The layered, lead-free hybrid perovskites are superior in organic electronics compared to their three-dimensional (3D) counterparts due to their facile synthesis and promising stability to various environmental conditions. To learn more about the multifunctional side of such materials, a layered perovskite (EDA)­CuCl4 [EDA is (CH2)2(NH3)2] crystal was grown in solution and crystallographically characterized by single-crystal X-ray diffraction. The crystal is thermally very stable and exhibits a high reversible thermochromic working temperature (∼503 K), intense conductivity changes with temperature, and strong exotic magnetic properties. The structural changes of the crystal with temperature are monitored and explained by powder X-ray diffraction and UV–vis absorption. The absorption band of the crystal shows little variation after repeated heating/cooling cycles, indicating admirable stability. Moreover, the Cu hybrid consists of a strong ferromagnetic interaction in antiferromagnetically coupled layers with a Néel temperature of about 34 K. The magnetocaloric effect of the crystal was investigated and found to be inverse due to the magnetic entropy change associated with the antiferromagnetic transition and the strong ferromagnetic interaction, indicating the suitability of the perovskite hybrid as a candidate for an environmentally friendly low-temperature magnetic cooling technology. The overall results promise a potential multipurpose two-dimensional (2D) perovskite for future electronic applications in a wide temperature range.