Photoisomerization‐Driven Photoluminescence Modulation in CdSeS Gradient Quantum Dot/Liquid Crystal Nanocomposites

Abstract

AbstractWe demonstrate that the photoluminescence in nanocomposites composed of gradient CdSeS quantum dots (QD) doped in a host nematic liquid crystal (LC) can be substantially modulated due to photoisomerisation of small amounts of an incorporated azobenzene‐based LC material. An attractive feature of this reversible second‐wavelength optical control is that it can be achieved with low magnitude (0.6 mW/cm2) actinic UV light, and thus has very little scope for undesirable photooxidation. The modulation magnitude is high (45 %) and lends itself to both spatial and temporal control. The dynamics of the process for the forward (UV‐on) process is much faster than the return to the equilibrium situation. However, by applying a DC bias field we show that this return can be accelerated by a factor of more than 6, which under ideal circumstances could even be 20. This low‐power second‐wavelength on‐demand optical technique for emission modulation is generic and holds promises for the development of light‐switchable QD‐based emissive displays and photonic devices.