Crystal Structure Features of CsPbBr 3 Perovskite Prepared by Mechanochemical Synthesis

LÓPEZ, CARLOS A.; ABIA, CARMEN; ALVAREZ-GALVÁN, MARÍA CONSUELO; HONG, BO-KYUNG; MARTÍNEZ-HUERTA, M. VICTORIA; SERRANO-SÁNCHEZ, FEDERICO; CARRASCOSO, FELIX; CASTELLANOS-GÓMEZ, ANDRÉS; FERNÁNDEZ-DÍAZ, M. TERESA; ALONSO, JOSÉ A.

ACS Omega

American Chemical Society

Lugar: Washington; Año: 2020 vol. 5 p. 5931 - 5938

2470-1343

We present a mechanochemical procedure, with solvent-free, greenchemistrycredentials, to grow all-inorganic CsPbBr3 perovskite. The crystal structureof this perovskite and its correlations with the physicochemical properties have beenstudied. Synchrotron X-ray diffraction (SXRD) and neutron powder diffraction(NPD) allowed us to follow the crystallographic behavior from 4 to 773 K.Unreported features like the observed negative thermal expansion of the b unit-cellparameter stem from octahedral distortions in the 4−100 K temperature range. Themechanochemical synthesis was designed to reduce the impact energy during themilling process, leading to a defect-free, well-crystallized sample characterized by aminimum unit-cell volume and octahedral tilting angles in the low-temperatureorthorhombic perovskite framework, defined in the Pbnm space group. The UV−visdiffuse reflectance spectrum shows a reduced band gap of 2.22(3) eV, and thephotocurrent characterization in a photodetector reveals excellent properties withpotential applications of this material in optoelectronic devices.