Highly Reproducible Organometallic Halide Perovskite Microdevices based on Top-Down Lithography

A top-down fabrication technology is proposed that can be utilized to fabricate high-quality organometallic-halide-perovskite-based devices. the microplates are synthesized with a solution-based one-step precipitation method. Equal volumes of CH₃NH₃Br (0.1 m) and PbBr₂ (0.1 m) in N,Ndimethylformamide are mixed together to form stock solution of CH₃NH₃BrPbBr₂ (0.05 m). The stock solution is then dip-cast onto an indium tin oxide (ITO)-coated glass substrate, which was coated with a thin polyethylene film. Then, the substrate is mounted on a Teflon stage in a 250 mL beaker containing 75 mL of dichloromethane. The beaker is sealed with a porous Parafilm (3 m) to control the evaporation process. In experiment, thin polyethylene film was scrubbed with tweezers before dip-casting the stock solution. The optical properties of such microplates are examined via optical excitation. At low pump densities, a broad emission peak with a 30 nm full width at half maximum (FWHM) can be observed at a central wavelength of 535 nm. The integrated output of this broad peak increases slowly with the pump density. While the synthesized perovskite microplate lasers show relatively high Q factors and low thresholds, these devices are hard to be employed in practical applications. This is because the synthesized perovskite microplates usually have random sizes and aspect ratios. This technique is not limited to the fabrication of microlasers but can also be extended to photodetectors and photovoltaic devices.