{"paper":{"title":"Blue Organic Light-Emitting Diodes with External Quantum Efficiencies over 20% Based on Europium(II) Emitters","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"A rigid europium(II) complex delivers 20.7 percent external quantum efficiency in a blue OLED.","cross_cats":["cond-mat.mtrl-sci"],"primary_cat":"physics.app-ph","authors_text":"Carsten Rothe, Felix Kaden, Mahmoud Soleimani, Roman Tkachov, Sebastian Reineke, Sebastian Schellhammer, Toni B\\\"arschneider","submitted_at":"2026-04-07T21:22:57Z","abstract_excerpt":"The realization of blue electroluminescence with high efficiency and lifetime remains a long-standing hurdle for organic light-emitting diode (OLED) technology to overcome. Divalent Europium [Europium(II)] complexes offer a fundamentally distinct pathway toward this goal, as their atomic 4f-5d transitions yield single-Gaussian, spectrally pure emission with theoretical 100% exciton utilization in electroluminescence and no involvement of fragile organic bonds in the emissive process. Here, we present a rigid aza-crown europium(II) complex (Eu5NHCrown) that achieves near-unity photoluminescence"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The complex sublimes without decomposition and can be vacuum-deposited into a bottom-emitting, single-host OLED architecture, delivering an external quantum efficiency (EQE) of 20.7% with minimal roll-off (19.3% at 1000 cd m-2) and a narrowband electroluminescence with CIE coordinates of (0.12, 0.25).","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the rigid aza-crown europium(II) complex maintains near-unity photoluminescence quantum yield after vacuum deposition and that this directly translates to the reported electroluminescence efficiency in the single-host device without additional losses or decomposition.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"A new europium(II) complex delivers 20.7% EQE in blue OLEDs with pure emission, minimal roll-off, and CIE coordinates of (0.12, 0.25).","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"A rigid europium(II) complex delivers 20.7 percent external quantum efficiency in a blue OLED.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"cd3adac988f333c61343cc9a709aeb8c830af623ab807674a09cbed9c5b2dceb"},"source":{"id":"2604.06476","kind":"arxiv","version":2},"verdict":{"id":"d03e01da-b704-4c83-8241-d2d3fd06aa39","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-10T17:48:29.615940Z","strongest_claim":"The complex sublimes without decomposition and can be vacuum-deposited into a bottom-emitting, single-host OLED architecture, delivering an external quantum efficiency (EQE) of 20.7% with minimal roll-off (19.3% at 1000 cd m-2) and a narrowband electroluminescence with CIE coordinates of (0.12, 0.25).","one_line_summary":"A new europium(II) complex delivers 20.7% EQE in blue OLEDs with pure emission, minimal roll-off, and CIE coordinates of (0.12, 0.25).","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the rigid aza-crown europium(II) complex maintains near-unity photoluminescence quantum yield after vacuum deposition and that this directly translates to the reported electroluminescence efficiency in the single-host device without additional losses or decomposition.","pith_extraction_headline":"A rigid europium(II) complex delivers 20.7 percent external quantum efficiency in a blue OLED."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.06476/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":1,"snapshot_sha256":"c2939c55840025c61cdd7a922bad757a2d0e164691e59a2159a48fd2d4351b82"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}