Improved thermal stability of CsPbBr3 quantum dots by ligand exchange and their application to light-emitting diodes

All-inorganic perovskite quantum dots (QDs) have superior optical characteristics and stability, and selecting ligands is of prime importance. Here, we investigated the thermal stability of CsPbBr3 QDs with different ligands and fabricated CsPbBr3 QD light-emitting diodes (QLEDs). Even after annealing at 220 degrees C, 61% of the initial photoluminescence intensity was maintained by spin-coated film of CsPbBr3 QDs capped with dihexadecyldimethylammonium bromide (QD-DHDAB). Such an improvement is attributed to the strength of the binding and thermal stability of the ligand itself. Furthermore, QLEDs with QD-DHDAB exhibited a maximum current efficiency of 9.76 cd A(-1), which is promising for the practical application of CsPbBr3 QLEDs. (C) 2019 The Japan Society of Applied Physics