CsPbBr3 perovskite quantum dots with enhanced stability and optical properties synthesized in situ passivation assisted with n-amylamine

CsPbBr 3 perovskite quantum dots (PQDs) have been considered as potential luminescent materials for lighting and display applications. The oleylamine (OLA) is usually considered to be an indispensable surface ligand in the synthesis of PQDs. However, the long-chain amines can cause more surface defects, resulting in the poor stability and optical performance, which will greatly limit its practical application. Herein, the n-amylamine (ALA) with short carbon chain has been chosen to replace the OLA as surface ligand to synthesize the CsPbBr 3 PQDs. Under the synergic action of oleic acid (OA), ALA-CsPbBr 3 PQDs with enhanced air/thermal stability and optical properties can be obtained through a modified hot-injection method. The ALA-CsPbBr 3 PQDs possess highly monodisperse cubic morphologies (∼10 nm edge lengths), which are similar to the OLA-CsPbBr 3 PQDs. Meanwhile, ligand substitution does not alter the crystal structure, and maintain the cubic crystal structure of CsPbBr 3 . The synthesized ALA-CsPbBr 3 PQDs exhibits a PLQY of 91.3 %, significantly higher than that of OLA-CsPbBr 3 (70.42 %). Photo-stability test indicates that ALA-CsPbBr 3 PQDs are markedly more stable than OLA-CsPbBr 3 PQDs, owing to the passivation of the surface defects. Furthermore, the activation energy of ALA-CsPbBr 3 PQDs (570.8 meV) is higher than OLA-CsPbBr 3 PQDs (495.4 meV), indicating the ALA-CsPbBr 3 PQDs have the much higher thermal stability. In addition, the ALA-CsPbBr 3 PQDs can also be efficiently excited by X-rays, showing a linear response to X-ray radiation, and have good X-ray imaging capability. The CsPbBr 3 PQDs with enhanced stability and optical properties, which are modified by short carbon-chain surface ligands, can further strengthen the competitiveness of PQDs for optoelectronic device applications.