Herein, two new solution-processable HLCT fluorophores (CBzF and CBzFC) based on benzothiadiazole (Bz) derivatives were designed and synthesized (HLCT = hybridized local and charge transfer). Their optical and photophysical properties were experimentally and theoretically studied and verified by the solvatochromic effect and density functional theory calculations. The two molecules demonstrate high solubility, HLCT features, and an intense green fluorescence with solid-state photoluminescence quantum yields of 63-72 %. Both fluorophores are effectively applied as non-doped emitters for solution-processed double-layered OLEDs, which produce intense green emission colors with low turn-on voltages (3.0-3.2 V). Specifically, the CBzFC-based solution-processed device achieves a high maximum luminescence (24400 cd m À 2 ), high maximum efficiencies (EQE max = 5.59 %, CE max = 12.24 cd A À 1 , and PE max = 10.54 lm W À 1 ), and decent efficiency low-off.

Here, a new solution-processable hybridized local and charge-transfer (HLCT) fluorescent molecule, CPBzFC, is designed and synthesized as an efficient emitter for low-cost and simple-structured electroluminescent devices. CPBzFC contains 7-(4-(carbazol-N-yl)phenyl)benzothiadiazole as...

Hybridized local and charge transfer (HLCT) is an attractive strategy for achieving efficient electroluminescence (EL) in electrofluorescent devices by the conversion of triplet‐state (T) to singlet‐state (S) excitons via a reverse intersystem crossing, giving rise to a high exciton utilization efficiency exceeding the spin statistical limit. Excellent device performance is reached using thermally evaporated emissive layers. However, for potential large‐scale commercialization, it is crucial to attain comparable device performances using low‐cost solution‐processing techniques. Herein, a new concept of dual HLCT characteristic fluorophore (BCBF) with a high solid‐state fluorescence as a nondoped emitter for a simple structured solution‐processed EL device is presented. BCBF is effectively formulated by π‐conjugation linking two HLCT fragments with a highly soluble hole‐transporting aromatic moiety. Its dual HLCT and photoluminescence (PL) properties are experimentally and theoretically probed by the solvatochromic effect and density functional theory (DFT) calculations. The molecule exhibits an intense yellow–green emission with a good solution‐processed film‐forming quality and a high solid‐state fluorescence quantum yield of 80%. BCBF is successfully utilized as a nondoped emissive layer in a solution‐processed double‐layered organic light‐emitting diode (OLED), which shows excellent EL performance (brightness of 47 580 cd m−2, current efficiency of 15.78 cd A−1, and external quantum efficiency of 7.20%).

The front cover artwork is provided by Phattananawee Nalaoh, VISTEC (Thailand). The image shows the solution‐processable hybridized local and charge‐transfer (HLCT) fluorophore as an efficient non‐doped emitter for solution‐processed double‐layered organic light‐emitting diode. Read the full text of the Research Article at 10.1002/cptc.202200154.

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