Light-Emitting Electrochemical Cells Based on Nanogap Electrodes

In a light-emitting electrochemical cell (LEC), electrochemicaldoping caused by mobile ions facilitates bipolar charge injectionand recombination emissions for a high electroluminescence (EL) intensityat low driving voltages. We present the development of a nanogap LEC(i.e., nano-LEC) comprising a light-emitting polymer (F8BT) and anionic liquid deposited on a gold nanogap electrode. The device demonstrateda high EL intensity at a wavelength of 540 nm corresponding to theemission peak of F8BT and a threshold voltage of & SIM;2 V at 300K. Upon application of a constant voltage, the device demonstrateda gradual increase in current intensity followed by light emission.Notably, the delayed components of the current and EL were stronglysuppressed at low temperatures (<285 K). The results clearly indicatethat the device functions as an LEC and that the nano-LEC is a promisingapproach to realizing molecular-scale current-induced light sources.

Automated summary

In a light-emitting electrochemical cell (LEC), electrochemical doping facilitates charge injection and recombination emissions, resulting in high electroluminescence (EL) intensity at low driving voltages. In this study, a nanogap LEC (nano-LEC) consisting of a light-emitting polymer (F8BT) and an ionic liquid on a gold nanogap electrode was developed. The device demonstrated high EL intensity and a low threshold voltage at 300K. At low temperatures (<285K), the delayed components of the current and EL were strongly suppressed, indicating the nano-LEC as a promising approach for molecular-scale current-induced light sources.