Patterned Size-controlled Perovskite Microcrystal Arrays And Their Applications In High Performance Tunable Microlasers

With advances in nanotechnology,the research on micro/nanolasers has become an advanced and essential topic because semiconductors can chemically/physically tune optoelectronic properties for high-performance nanoscale applications via rational design and composition control,propelling the development of on-chip optical communication.Recently,the organic-lead halide perovskites?OHPs?have been considered a type of high-performance semiconductors because of their high absorption coefficients,tunable wavelengths,long carrier lifetimes,micrometer-scale diffusion lengths and so on.Since the first demonstration of ultra-stable amplified spontaneous emission?ASE?from perovskite thin films,many types of perovskite microlasers have been experimentally realized by different groups.However,in this context of rapid development,many problems remain unsolved,especially the instability of OHPs due to the susceptibility to hydrolysis.Hereby,a feasible method is to completely substitute the organic cation with cesium.Compared with OHPs,all-inorganic perovskites exhibit much better stability and similar high optoelectronic properties,guaranteeing a longer usage and suppression of optical loss.Additionally,single-crystalline halide perovskites with regular morphology are of great significance for laser applications because they can be used to fabricate a natural whispering-gallery-mode resonator.Although enormous efforts have been put to synthesize single-crystalline perovskites,controlling the lateral size and thickness of the crystal,particularly at the nanoscale,is still challenging.Here,we report a facile and high-throughput strategy to construct surface-tension-confined droplet array via the difference of hydrophilic and hydrophobic on chemically modified substrate surface.And by evaporative assembly,the micro/nanoscale size-controlled all-inorganic perovskite single-crystal arrays were selectively one-step created.The method adjusts the size of the pattern and dewetting process,can be used to easily tune the single crystal size and selectively position the single crystal,with versatility in fabricating perovskite single-crystal arrays in wafer scale.When the patterned size increased from 2 to 28?m,the width of the Cs Pb Cl Br₂perovskite microplates increased from 150 nm to 4.2?m.Fixing the width of the microplates at 1.6?m,with the increase of the sliding speed from 50 to 250 mm/min,we could significantly control the thicknesses from 270 nm to 430 nm.Additionally,our present study provides a characterization of lasers based on different three-dimensional structures,confirming their width-dependence lasing mode and thickness-dependence lasing threshold characteristic,which is beneficial for the tunability of high-performance microlaser.