Session: Nanomaterials:

Metal halide perovskites are one of the most investigated materials in optoelectronics, with their lead-based counterparts being renowned for their enhanced optoelectronic performance. The 3D CsPbX₃ structure has set the standard with many studies currently attempting to substitute lead with other metals while retaining the properties of this material. This effort has led to the fabrication of lower dimensional 2D, 0D, etc. metal halides. Recently, the layered perovskite structures have captured attention as inspiration for a new generation of colloidal semiconductors.

Here we report the colloidal preparation of the Ruddlesden – Popper phase Cs₂CdCl₄:Sb³⁺, using a facile hot injection approach under atmospheric conditions. Through strict adjustment of the synthesis parameters with emphasis on the ligand ratio, we obtained nanoplatelets with relatively uniform size and good morphological control. The particles were characterized through synchrotron X -ray diffraction, an analysis that confirms the aforementioned phase. Rietveld Refinements were carried out that assigned a I4/mmm tetragonal space group to the particles and subsequent texture analysis affirmed a disk-like morphology with a ~20nm diameter and a ~1.8nm thickness along the c-axis The spectroscopic characterization revealed most strikingly an intense blue-green emission under UV excitation, with a measured PLQY of ~20%. The emission is attributed to the doped Sb³⁺ within the structure. A similar behaviour was previously reported in Sb³⁺ doped double-layered perovskites, where spectroscopic analysis indicated that the emission is a result of an s-p transition and originates from self-trapped excitons from the Sb³⁺ hosts.

(a) HRTEM and (b) TEM imaging gave average particle diameters ranging from ~20nm to ~30nm and displayed a tendency of the particles to self-assemble when in concentrated solutions. (c) UV-vis absorption and PL/PLE measurements showed a confined absorption peak at 320nm and a broad emission peak centered at 545nm; inset: emission under UV light.

(a) HRTEM and (b) TEM imaging gave average particle diameters ranging from ~20nm to ~30nm and displayed a tendency of the particles to self-assemble when in concentrated solutions. (c) UV-vis absorption and PL/PLE measurements showed a confined absorption peak at 320nm and a broad emission peak centered at 545nm; inset: emission under UV light.

Margarita Samoli

Phd Student, Gent University

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