Stable all‐inorganic perovskite quantum dots using a ZnX2‐trioctylphosphine‐oxide and a new hole transporting polymer in PeLEDs

Abstract

Highly stable perovskite quantum dots (PeQDs) are developed using excess Zn precursor and trioctylphosphine‐oxide (TOPO). They not only have high quantum efficiency and sharp full width at half maximum values (15–30 nm) but also have improved long‐term stability at high temperature. They have EQE (%) and current efficiency (Cd A−1) of (7.12%, 9.93 Cd A−1) for red, (6.06%, 32.5 Cd A−1) for green, and (0.56%, 0.88 Cd A−1) for blue‐emitting devices, respectively. Also, a new hole-transporting material, poly-2-(9Hcarbazol-9-yl)-5-(4-vinylphenyl)-5H-benzo[b]carbazole (PBCZCZ), was developed for perovskite light-emitting diodes (PeLEDs). The EQE of the green PeLEDs using PBCZCZ was about 2.5 times higher and that of the sky-blue PeLEDs was about 3 times higher than the device made with the commercial HTL of PVK. The operational device lifetimes of the green and sky-blue PeLEDs made with PBCZCZ were about 4.1 and 4.8 times higher than the PVK-containing device.