Tailoring Photoluminescence by Strain-Engineering in Layered Perovskite Flakes br

Strain is an effective strategy to modulate the optoelectronicproperties of 2D materials, but it has been almost unexplored in layered hybridorganic-inorganic metal halide perovskites (HOIPs) due to their complex bandstructure and mechanical properties. Here, we investigate the temperature-dependent microphotoluminescence (PL) of 2D(C6H5CH2CH2NH3)2Cs3Pb4Br13HOIP subject to biaxial strain induced by aSiO2ring platform on whichflakes are placed by viscoelastic stamping. At 80 K,we found that a strain of < 1% can change the PL emission from a single peak(unstrained) to three well-resolved peaks. Supported by micro-Raman spectros-copy, we show that the thermomechanically generated strain modulates the bandgap due to changes in the octahedral tilting andlattice expansion. Mechanical simulations demonstrate the coexistence of tensile and compressive strain along theflake. Theobserved PL peaks add an interesting feature to the rich phenomenology of photoluminescence in 2D HOIPs, which can beexploited in tailored sensing and optoelectronic devices

Automated summary

Strain was applied to a 2D organic-inorganic metal halide perovskite to study its temperature-dependent microphotoluminescence. The results showed that strain can modulate the emission spectrum and band structure, with both tensile and compressive strain observed on the flake surface.