Journal Article ASE threshold Crystalline‐assembly Delayed fluorescence Donor–acceptor molecules Electron–phonon coupling Lattice vibrations Rashba band structures Review Slow phonon dynamics amplified spontaneous emission circularly‐polarized luminescence crystallite size hole extraction hot-carrier cooling ligand exchange light‐emitting optical gain organic–inorganic hybrid metal halide perovskites perovskite quantum dots  re-assembling process short-circuit current density spin‐orbital coupling transport layer engineering