Broad Orange Emission from Piperazine-Based Layered Halide Perovskites

Area of Science:

• Materials Science
• Solid-State Chemistry
• Optoelectronics

Background:

• Layered halide perovskites possess excellent optoelectronic properties.
• These materials are crucial for developing advanced devices like solar cells, LEDs, and photodetectors.

Purpose of the Study:

• To synthesize and characterize five new two-dimensional (2D) halide perovskites.
• To investigate their optical properties, including band gaps and emission characteristics.
• To explore the potential of these materials for optoelectronic applications.

Main Methods:

• Synthesis of five novel 2D halide perovskites: (C6H14N2)PbBr4, (C8H18N2)PbBr4·H2O, (C6H14N2)PbI4, 1-(C8H18N2)PbI4, and 2-(C8H18N2)PbI4.
• Characterization of optical properties, including measurement of optical band gaps.
• Analysis of photoluminescence spectra to determine emission peaks, full width at half-maximum (fwhm), and Stokes shifts.

Main Results:

• The synthesized compounds exhibited optical band gaps ranging from 2.63 to 3.35 eV.
• (C6H14N2)PbBr4 displayed orange emission (peak at 624 nm, fwhm 246.8 nm, Stokes shift 237 nm).
• (C8H18N2)PbBr4·H2O showed a larger Stokes shift (286 nm) attributed to exciton self-trapping, a key feature in 2D materials.

Conclusions:

• The study successfully expanded the known database of 2D halide perovskites.
• The observed significant Stokes shift in (C8H18N2)PbBr4·H2O highlights its potential for light-emitting applications.
• These findings offer valuable insights for the advancement of next-generation optoelectronic technologies.