Affiliation:
1. BK21 Four R&E Center Department of Chemical and Biological Engineering Korea University 145 Anam‐ro, Seongbuk‐gu Seoul 136–713 Republic of Korea
Abstract
AbstractPoly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), the most widely used hole injection layer (HIL) for perovskite light‐emitting diodes (PeLEDs), has a large hole injection energy barrier and easy charge separation at PEDOT:PSS/perovskite layer. Here, a self‐assembling molecule (SAM) called (2‐(3,6‐dimethoxy‐9H‐carbazol‐9‐yl)ethyl) phosphonic acid (MeO‐2PACz) is introduced as an interlayer between PEDOT:PSS and perovskite to overcome the limitations of PEDOT:PSS HIL. The MeO‐2PACz interlayer facilitated hole injection due to the reduced hole injection energy barrier and the improved hole mobility, enhanced photoluminescence (PL) due to the prevented charge transfer from perovskite into PEDOT:PSS, and reduced interface trap density due to the passivation of methoxy and carbazole group toward perovskite. As a result, PeLEDs with MeO‐2PACz interlayer has greatly enhanced maximum luminance (Lmax = 17,310 cd m−2) and reduced leakage current, resulting in higher maximum external quantum efficiency (EQEmax = 21.50%) compared to pristine Control device (EQEmax of 4.82%).
Funder
National Research Foundation of Korea
Ministry of Science, ICT and Future Planning