Color-Tunable Quantum Well Based Organic Light-Emitting Device

The development of efficient organic light emitting devices (OLEDs), particularly those based on thermally activated delayed fluorescence (TADF), is quite often struggling from high non-radiative recombination rate and exciton quenching in case of the neat film, which is frequently usual for complex host-guest systems. This study proposes an alternative multiple quantum well architecture to achieve controlled color modulation and flexible emissive performance using a solvatochromic acceptor orange-red emitter, NI-3TPA. By utilizing mCBP as the wide-bandgap barrier layer, OLEDs featuring varying quantum well thickness (3nm to 7 nm) were fabricated and systematically evaluated against the non-doped device as well as referenced host-guest structure.The results demonstrate that modifying the mCBP barrier thickness directly influences electroluminescent characteristics. Specifically, reducing the barrier to 3nm enhances the carrier tunneling probability, thereby effectively suppressing exciton quenching. The optimized 3nm quantum well based device demonstrated a reduced turn-on voltage of 5.6 V and achieved a maximum external quantum efficiency (EQE) of 2.03 % which outperforms the 7nm device (1.07 %) and the neat-film device (0.83 %). All fabricated devices exhibited strong light emitting within. red-to-orange CIE1931 color coordinates.The proposed architecture demonstrates precise tuning of the electroluminescence spectrum, exhibiting a redshift from 566nm to 578 nm as the potential well width increased due to the quantum confinement effect. This paper concludes that the quantum well strategy provides a reproducible approach for localizing charge carriers and excitons within the emissive layer, mitigating parasitic processes and side effects such as intermolecular and exciton quenching without complex fabrication processes.