[en] In this paper, the morphology of CsPbBr₃ nanocrystals (NCs) is controlled by changing the molar ratios of oleylamine (OAm) and propionic acid (PA). The relative ratio plays an important role in the evolution of morphology. The CsPbBr₃ NCs exhibit monoclinic morphology when the molar ratio of OAm/PA is equivalent. When the molar ratio of OAm/PA deviates from 1:1, CsPbBr₃ NCs tend to grow in a sheet shape. The nanosheets with 200∼500 nm and thickness ∼15 nm were synthesized as the molar ratio of OAm/PA (1:4). The PL intensity decreases with the increase of size. The fluorescence lifetime shows a trend of gradual shortening. (paper)

[en] Highlights: • The V_Br of CsPbBr₃ NCs can be effectively reduced by adding 1,9-DN in the solution. • The CsPbBr₃ NCs prepared with 1,9-DN have a good ethanol tolerance. • The illumination and thermal stability of CsPbBr₃ NCs was obviously improved. -- Abstract: Despite colloidal CsPbBr₃ nanocrystals (NCs) exhibit an excellent optoelectronic characteristics, the stability greatly restricts their potential applications due to the ionic nature. The CsPbBr₃ NCs were synthesized in a Br-rich strategy by adding 1,9-DN. The PL intensity of CsPbBr₃ NCs was increased and the average PL decay lifetime was reduced due to the decrease of defects. The chemical, illumination and thermal stability of CsPbBr₃ NCs were obviously improved, which may be caused by the increase of ligand and the decrease of V_Br on the surface of CsPbBr₃ NCs as adding 1,9-DN. The results provide a novel strategy to prepare emissive materials with environmental stability, implying great promise in optoelectronic applications.

[en] The FM exchange is gradually enhanced in the EuTi_1-xNi_xO₃ (x = 0.05, 0.1) compounds. There are two successive magnetic transitions around liquid helium temperature, and exhibit a giant reversible magnetocaloric effect. The maximum values of magnetic entropy change are 41.9 and 45.5 J/kg K, and the refrigerating capacity were evaluated to be 336.5 and 359.5 J/kg for a field change of 5 T. Especially, for a field change of 1 T, the maximum value of magnetic entropy change is 13.7 J/kg K, the refrigerating capacity reach to 53.4 J/kg, and adiabatic temperature change is 4.1 K for EuTi_0.9Ni_0.1O₃, respectively.