For the synthesis of the CsPbBr3 NCs, a hot injection method was involved. In brief, ODE (10 mL) and OA (630 µL) were introduced to Cs2CO3 (203.5 mg) and subjected to degassing at 120 ˚C for 1 hour. At this point, the color of the solution turned to mild yellow, indicating that cesium reacted with OA(Cs-OA). Then, this solution was heated to 150 ˚C under N2 gas for 1 hour.