Double-locked narrowband hybrid locally-excited and charge-transfer emitter exhibiting amplified spontaneous emission

Abstract

<p>Hybrid Locally-excited and Charge-Transfer (HLCT) materials have garnered significant attention for their high exciton utilization efficiency in organic light-emitting diodes (OLEDs). However, conventional HLCT materials suffer from broad emission, which limits their applications. In this study, we report a narrowband HLCT emitter, namely 10-(dimesitylboranyl)-8,8,12,12-tetraphenyl-8,12-dihydrobenzo[9,1]quinolizino[3,4,5,6,7-<i>klmn</i>]phenoxazine (PXZ-DL), incorporated by double-locked intramolecular connection. PXZ-DL exhibits a narrow emission spectrum with a small full width at half-maximum (FWHM) of 35 nm and 47 nm in solution and as an OLED emitter, respectively. Moreover, PXZ-DL demonstrates a high photoluminescence quantum yield of 100% and an external quantum efficiency of 8.0%. Additionally, PXZ-DL demonstrates excellent performance in amplified spontaneous emission with a low threshold of 5.7 μJ cm<sup>-2</sup> and a narrow FWHM of 11 nm. The intramolecular lock strategy offers a promising approach for the development of HLCT materials with high color purity.</p>