Polymorph-Dependent Electrogenerated Chemiluminescence of Low-Dimensional Organic Semiconductor Structures for Sensing

A sensitive electrogenerated chemiluminescence (ECL) sensor with an organic semiconductor as active material for detecting trace amounts of molecules has been highly desired. However, the crystal structure responses of the ECL properties of the organic semiconductor materials, that is, structure property relationship, is not clear, which limits the development of the sensitive ECL sensors. Herein, for the first time, we reported a novel concept for molecular-stacking-arrangement-dependent electrogenerated chemiluminescence properties of organic semiconductor rubrene microstructures. The rubrene 1D microwires and 2D hexagonal plates with different polymorphs (triclinic and monoclinic) were controllably constructed with the reprecipitation method. The supersaturation of the rubrene molecules plays an important role in the thermodynamically and kinetically dominated process of growth, which affects not only the polymorphs but also the morphology of the obtained microstructures. These microstructures show good optoelectronic properties, which are used as active ECL materials for the construction of ECL sensors. The ECL sensors exhibited distinct electrogenerated chemiluminescence properties, probably related to different inherent crystal-structure dependent triplet triplet annihilation rate and charge-transfer rate. The sensors manifested electrogenerated chemiluminescence responses in broad linear range for the monitoring of creatinine molecules.