Bright and spectrally stable pure-red CsPb(Br/I)3 quantum dot LEDs realized by synchronous device structure and ligand engineering

All-inorganic CsPbBrxI3_x perovskite quantum dots (PQDs) show great potential for pure-red light-emitting diodes (LEDs). However, spectral instability caused by ion migration at high electric fields and lower luminance limit its practical applications. Here, the ITO/ZnO/PEI/CsPbBrxI3_x PQDs/N, N, N-tris (4-(9-carbazolyl) phenyl) amine (TCTA) (3 nm)/1-bis [4-[N, N-di(4-tolyl)amino]-phenyl]-cyclohexane (TAPC)/MoO3/Au device structure is first designed to reduce the overall operating voltage of the device by enhancing hole injection and transport, effectively avoiding ion migration under high electric fields, and then by post-treating CsPbBrxI3_ x PQDs with noctylphosphonic acid: K to remove surface defects and increase the activation energy of halogen migration, further suppressing ion migration while improving the optical properties of the material. Ultimately, the colorstable pure-red perovskite LED achieved a high luminance of 13730 cd m_ 2 at voltages as low as 4.9 V and a maximum EQE of 16.7%.

Automated summary

A color-stable pure-red perovskite LED with low operating voltage and high luminance was achieved by optimizing the device structure and using chemical treatment methods.