Optimising reaction conditions in flasks for performances in organic light-emitting devices

Abstract

A method for correlating reaction conditions with device performance was developed by combining Design-of-Experiments and machine-learning strategies in multistep device fabrication processes. This method allowed the "from-flask-to-device" optimisation of a macrocyclisation reaction yielding a mixture of methylated [n]cyclo-meta-phenylenes, and a crude raw material was directly applied to the fabrication of Ir-doped organic light-emitting devices via spin-coating. The method succeeded in eliminating energy-consuming and waste-producing separation and purification steps during device fabrication. The device using the optimal raw mixture material recorded a high external quantum efficiency of 9.6%, which surpassed the performance of purified materials. The raw material method was also found to be applicable to screen-printing processes, and image-transferred OLEDs were fabricated using the low-cost, environmentally benign materials.