Low Dimensional Lead-Free Chiral Perovskite Quantum Dots.

Xiaomei Jiang, Iaonnis Spanopoulos, Emmanuel Olawale, Ali Amzy.

University of South Florida

Low-dimensional lead-free chiral perovskites are gaining interest in materials research due to their potential use in chiral optoelectronic and spintronics devices, particularly the application in spin filter due to their strong spin selectivity. While most current choices of chiral metal halide perovskites contain lead, a toxic and environmentally harmful element, the search for a lead-free counterpart is the motive behind current work. Here we show the successful synthesis of a 0D perovskites quantum dot, (NEA)₂(MCHA)₂Bi₂Br₁₀, into thin films using spin coating method. The films are found to be stable in air after 72 hours, with a band gap of approximately 2.77eV and photoluminescence of 2.27eV. Raman spectroscopy revealed a few strong modes from the organic layer and inorganic octahedral. Distinctive circular dichroism was present which matches the derivative of the absorption spectrum, confirming the transfer of chirality from organic to inorganic moiety. Due to its intrinsic inversion symmetry breaking induced by the chirality, the material will be suitable to study circular photogalvanic effect, which is our future aim. This material might be a candidate for tandem perovskites solar cells based on its optical properties.

Oral Presentation