The rational design of a new class of photoresponsive tris­(8-hydroxyquinolinato)­aluminum­(III) (Alq3) complexes has been developed. By incorporating the photochromic dithienylethene units with different peripheral heterocycles into the Alq3 framework, the photochromic properties as well as photoswitching efficiency can be readily modulated, through effective photocyclization of the Al­(III) complex. Such intrinsic photochromic behavior leads to the unprecedented enhancement in the electron-transporting properties as demonstrated by the as-fabricated electron-only device, rendering the realization of photoswitchable electron mobility. In addition, one of these complexes is capable of serving as an active layer for solution-processable resistive memory devices. Photocontrollable memory performance has been achieved with a binary memory behavior, with high ON/OFF ratio and long retention time. This work represents not only the first example of photoresponsive Alq3-based electron-transporting materials but also the solution-processable Alq3-based optical and resistive memory devices with photocontrollable performance.

A class of dithienylethene-containing boron­(III) diketonates with long alkoxy chains, together with their corresponding β-diketone ligands, has been prepared and characterized. The photophysics, electrochemistry, and photochromism of the compounds have been investigated. Some of them exhibit gelation behavior, which has been explored by variable-temperature UV–vis absorption studies, and the morphology of the gels has been studied by electron microscopy. In addition, the organogels have been found to be photoresponsive with color changes under photoexcitation, leading to the construction of multiresponsive boron­(III) diketonate-based materials.

A series of dithienylethene-containing boron(III) ketoiminates, as well as their corresponding β-ketoimine ligands, have been synthesized and characterized. The photophysical, electrochemical, and photochromic properties of the compounds have been studied. Photocyclization has been found to be suppressed upon introduction of a phenyl substituent on the nitrogen atom of the β-ketoiminate core, whereas photochromism could be observed by replacement of the phenyl substituent with a bulky mesityl group. It is believed that the steric effect of the mesityl unit restricts molecular rotation, resulting in such a prominent difference in the photochromic properties.