In situ interfacial passivation with an arylphosphine oxide and phosphonate electron transporting layer for efficient all-solution-processed PeQLEDs

Abstract

Perovskite quantum dot light-emitting diodes (PeQLEDs) have emerged as a promising candidate for high-quality lightings and displays, where an electron transporting layer (ETL) is required to achieve balanced charge transport and thus high performance. However, the ETL is often thermally-deposited under vacuum, since the low-cost solution process would damage the underlying perovskite quantum dots (PeQDs). Here, we demonstrate efficient all-solution-processed PeQLEDs based on arylphosphine oxide (SPPO13) and phosphonate (TPPO) as the ETL. Benefitting from the coordination between PO and exposed Pb atoms, in situ interfacial passivation occurs during the solution deposition of SPPO13 or TPPO on PeQDs. As a result, bilayer films (PeQDs/ETL) exhibit improved photoluminescence quantum yields and prolonged lifetimes compared with single layer PeQDs. Correspondingly, all-solution-processed PeQLEDs are fabricated successfully via an orthogonal solvent strategy, revealing bright green emission with a promising current efficiency of 24.1 cd A⁻¹ (12.1 lm W⁻¹, 6.47%) and CIE coordinates of (0.12, 0.79).