  Solution-based perovskite nanoparticles have been intensively studied in past
few years due to their applications in both photovoltaic and optoelectronic
devices. Here, based on the common ground between the solution-based perovskite
and random lasers, we have studied the mirrorless lasing actions in
self-assembled perovskite nanoparticles. After the synthesis from solution,
discrete lasing peaks have been observed from the optically pumped perovskites
without any well-defined cavity boundaries. The obtained quality (Q) factors
and thresholds of random lasers are around 500 and 60 uJ/cm2, respectively.
Both values are comparable to the conventional perovskite microdisk lasers with
polygon shaped cavity boundaries. From the corresponding studies on laser
spectra and fluorescence microscope images, the lasing actions are considered
as random lasers that are generated by strong multiple scattering in random
gain media. In additional to conventional single-photon excitation, due to the
strong nonlinear effects of perovskites, two-photon pumped random lasers have
also been demonstrated for the first time. We believe this research will find
its potential applications in low-cost coherent light sources and biomedical
detection.
