Quantum mechanics

Photochemistry

Materials science

Phosphorescence

Layer (electronics)

Thin-film transistor

Atomic physics

Pentacene

Molecule

Electroluminescence

Diode

Physics

Quantum efficiency

Nanotechnology

Organic chemistry

Singlet state

Luminescence

Fluorescence

Phosphorescent organic light-emitting diode

Excited state

Sulfur

OLED

Chemistry

Optoelectronics

Angewandte Chemie International Edition

Highly efficient organic thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) emitters for organic light‐emitting diodes (OLEDs) generally consist of a twisted donor–acceptor skeleton with aromatic amine donors. Herein, through introducing sulfur atoms into isomeric pentaphene and pentacene frameworks, we demonstrate a set of polycyclic luminophores exhibiting efficient TADF and RTP characters. The incorporation of sulfur atoms confirms a folded molecular plane, while intensifies singlet–triplet spin‐orbit coupling. Further, the isomeric effect has a significant effect on the electronic structure of excited state, giving rise to the investigated compounds tunable luminescence mechanisms of TADF and RTP. With efficient triplet harvesting ability, maximum external quantum efficiencies up to 25.1 % and 8.7 % are achieved for the corresponding TADF and RTP OLEDs, verifying the great potential of sulfur‐bridged frameworks for highly efficient devices.

Molecular Engineering of Sulfur‐Bridged Polycyclic Emitters Towards Tunable TADF and RTP Electroluminescence