Amplified Spontaneous Emission and Carrier Dynamics in Ruddlesden–Popper and Dion–Jacobson Quasi‐2D Perovskite

Ruddlesden–Popper (RP) and Dion–Jacobson (DJ) quasi‐2D perovskites exhibit disparate chemical bonds and structures due to distinct organic spacer cations, endowing them with distinctive physical properties. A more far‐reaching investigation of the fundamental structure–physical relation, including the carrier dynamics, is expected in these layered perovskites. The phase distribution, defect state density, and ultrafast dynamics of RP‐type perovskite (PA) 2 () 3 and DJ‐type perovskite (HDAD) () 3 were investigated by using transient absorption spectra. The DJ‐type perovskite exhibits a lower threshold amplified spontaneous emission (ASE); however, its Auger recombination is more severe than that of RP‐type perovskite. By adding a trace amount of HBr to the solvent during crystal growth, exciton–phonon coupling was inhibited, energy transfer was promoted, and the Auger recombination was suppressed. We ultimately chose the HBr‐treated HDAD quasi‐2D perovskite thin films, achieving a low ASE threshold and high‐performance single‐mode green lasers.