Superlinear emission in bare perovskite: amplified spontaneous emission in disordered film versus single crystal lasing

We present an experimental study concerning the superlinear emission in organic-inorganic halide perovskites. Microphotoluminescence experiments under CW and picosecond excitation condition at low temperature and near field optical photoluminescence spectra at room temperature provide clear evidence of the very different origin of the superlinear regime in disordered films and microplates/microwires. Insights on the origin of modal structures of the emission spectra in the high excitation regime will be given by polarization-resolved photoluminescence experiments.