[O12-25]
Bifunctional Ligands Enable Tunable Transition Dipole Moment Alignment in Perovskite Nanocrystal Light Emitting Diodes
발표자Weiyang Zhou (전북대학교)
연구책임자강재욱 (Department of Flexible and Printable Electronics, LANL-JBNU Engineering Institute-Korea, Jeonbuk National University)
Abstract
Perovskite nanocrystal light emitting diodes suffer from severe optical losses, in which the orientation of transition dipole moments (TDMs) plays a decisive role in governing photon outcoupling. Here, we systematically investigate how nanocrystal shape and stacking behavior regulate the orientation of TDMs in the emissive layer. A facile ligand-exchange strategy using bifunctional 1,5-naphthalenedisulfonic acid (NDSA) is introduced to promote long-range NC stacking and tailor the dielectric environment, thereby enhancing the preferential in-plane alignment of TDMs. As a result, the fraction of in-plane TDMs increases from 60% to 70%, leading to a substantial improvement in light outcoupling efficiency (ηout) from 16.15% to 20.09%. Benefiting from the optimized optical configuration, the resulting devices achieve a peak external quantum efficiency (EQE) of 22.63% at 5127 cd m-2, maintain EQE above 20% over a wide luminance range of 400-8000 cd m-2.