Search

In article number 1805553, Yanxia Cui, Shengzhong Liu, and co‐workers report a record‐low‐threshold laser based on atomically smooth triangular nanoplatelet perovskite. Such perovskite nanoplatelets are obtained by fabricating atomically smooth PbI2 nanoplates and converting them to atomically smooth perovskites. The laser emissions have record‐low‐thresholds and high‐quality factors, thus making the scheme suitable for implementation of semiconductor nano‐lasers in a wide range of applications. [ABSTRACT FROM AUTHOR]

Single‐crystalline perovskites are ideal candidates for lasing and other optoelectronic applications. Although significant efforts have been made to grow both bulk single‐crystalline perovskites in liquid solution, their dimensions are still too large to make nanoscale whispering‐gallery‐mode (WGM) resonator based lasers that possess high quality (Q) factor and small volume. Besides, most reported perovskite resonators do not possess atomically smooth surfaces and facets, which limits the Q and thereby increases the lasing threshold. Here, atomically smooth triangular PbI2 templates are fabricated on a mica substrate by the vapor phase deposition method and are converted to atomically smooth perovskites which have regular and unwrinkled facets with average surface roughness less than 2 nm. By using a CH3NH3PbI3 nanoplatelet with a side length of 27 µm and thickness of 80 nm, room temperature WGM lasing with a Q up to 2600 is demonstrated, the highest reported for hybrid organic–inorganic perovskite nanoplatelets. In addition, the volume of the WGM mode is reduced significantly in comparison with the prior reports. The realized high‐quality triangular CH3NH3PbI3 perovskite nanoplatelets with high Q factor and small volume are expected to perform as ideal cavities for long pulse durations lasers and would find potential applications in integrated optoelectronic devices. Resonators that possess atomically smooth surfaces and facets are of critical importance for low‐threshold lasers. Here, atomically smooth CH3NH3PbI3 perovskite nanoplatelets with an average surface roughness less than 2 nm, which exhibit room temperature whispering gallery mode lasing with quality factors up to 2600, the highest reported for hybrid organic–inorganic perovskite nanoplatelets, are fabricated. [ABSTRACT FROM AUTHOR]