Transient Leakage\nElectroluminescence of Quantum-Dot\nLight-Emitting Diodes

Parasitic\nemission or leakage emission caused by electron leakage\nto a hole transport layer in quantum-dot light-emitting diodes (QLEDs)\ncritically impacts device efficiency and operational stability. The\nbuildup dynamics of such emission channels, however, was insufficiently\nresearched. Herein, we investigate transient electroluminescence dynamics\nof leakage emission in red/green/blue (R/G/B) QLEDs and reveal notable\ncontrast for R and G. In RQLEDs, leakage emission exhibits delayed\nturning-on than primary emission, which is attributed to much slower\nfilling up from lower-energy electron states and the initial quenching\nby nonradiative recombination with trapped holes. For GQLEDs, leakage\nemission turns on much more concurrently, and emission preferably\nstarts from higher energy states. For R/G QLEDs, under varied offset\nvoltage modulation, the current efficiency of primary emission is\ninvert-correlated to leakage emission, reconfirming leakage emission\nas a loss indicator.