Thermal Properties of Polymer Hole-Transport Layers Influence the Efficiency Roll-off and Stability of Perovskite Light-Emitting Diodes

While the performance of metal halideperovskite light-emittingdiodes (PeLEDs) has rapidly improved in recent years, their stabilityremains a bottleneck to commercial realization. Here, we show thatthe thermal stability of polymer hole-transport layers (HTLs) usedin PeLEDs represents an important factor influencing the externalquantum efficiency (EQE) roll-off and device lifetime. We demonstratea reduced EQE roll-off, a higher breakdown current density of approximately6 A cm(-2), a maximum radiance of 760 W sr(-1) m(-2), and a longer device lifetime for PeLEDs usingpolymer HTLs with high glass-transition temperatures. Furthermore,for devices driven by nanosecond electrical pulses, a record highradiance of 1.23 MW sr(-1) m(-2) andan EQE of approximately 1.92% at 14.6 kA cm(-2) areachieved. Thermally stable polymer HTLs enable stable operation ofPeLEDs that can sustain more than 11.7 million electrical pulses at1 kA cm(-2) before device failure.

Automated summary

The thermal stability of polymer hole-transport layers (HTLs) is found to be crucial for the performance and lifetime of metal halide perovskite light-emitting diodes (PeLEDs). PeLEDs with high glass-transition temperature polymer HTLs exhibit reduced external quantum efficiency (EQE) roll-off, higher breakdown current density, maximum radiance, and longer device lifetime. Furthermore, these devices driven by nanosecond electrical pulses achieve record-breaking radiance and EQE. The use of thermally stable polymer HTLs enables PeLEDs to sustain millions of electrical pulses before device failure.