Effect of surface ligand density on the amplified spontaneous emission properties of CsPbI2Br quantum dots

In recent years, amplified spontaneous emission (ASE) properties of all-inorganic perovskite quantum dots have attracted the interest of many researchers. Here, CsPbI2Br quantum dots (QDs) were synthesized by the hot injection method, and the effect of the purification process on the ASE properties of QDs has been investigated. In the purification process, n-hexane and ethyl acetate (EtOAc) are used as solvent and antisolvent, respectively. The results show that the volume ratio of n-hexane vs EtOAc has a remarkable effect on the optical performance. When the volume ratio is 1:5, the QDs have a larger size which increases the light scattering and absorption cross-section, thus achieving the lowest ASE threshold of 0.301 mJ/cm2. This work not only provides a facile strategy to obtain a low threshold of CsPbI2Br QDs but also enriches the application prospects of perovskite lasers.