Solvent Recrystallization-Enabled Green Amplified Spontaneous Emissions with an Ultra-Low Threshold from Pinhole-Free Perovskite Films

Green and amplified spontaneous emissions with low thresholds are crucial for the development of solution-processable perovskite light sources. Although mixed-cation CsPbBr3 perovskites are highly promising, pinholes are inevitably formed during the spin-coating process, which results in considerable optical losses. This study proposes a solvent recrystallization strategy to reduce the number of pinholes and enhance the crystallinity of (Cs, FA, MA)PbBr3/NMA (FA = CH(NH2)(2), MA = CH3NH3, and NMA = C11H9NH3) films in a dimethyl sulfoxide gas environment. Amplified spontaneous green emissions are produced with a low threshold of 1.44 mu J cm(-2) and a high net modal gain of 1176 cm(-1). The reduced threshold is attributed to the relatively low propagation loss and suppressed Auger recombination, which results from the formation of a pinhole-free surface and enlarged grain size. These results can be utilized in the development of high-performance perovskite laser devices.

Automated summary

A solvent recrystallization strategy was proposed to reduce the number of pinholes in perovskite films, resulting in amplified spontaneous green emissions with a low threshold and high net modal gain. The reduced threshold is attributed to low propagation loss and suppressed Auger recombination, which are achieved by forming a pinhole-free surface and enlarging grain size.