Multifunctional solid-state electrochemiluminescence sensing platform based on poly(ethylenimine) capped N-doped carbon dots as novel co-reactant

•A novel composite, PEI capped N-doped carbon dots (NCDs@PEI), was prepared via a facile microwave-assisted method.•The as-prepared NCDs@PEI exhibited low toxicity and high catalytic effect to the anodic ECL of Ru(bpy)32+ nanosheets.•Reduced graphene oxide (rGO) was introduced to accelerate electron transfer rate and amplify the ECL signal.•The fabricated ECL sensor exhibited multifunctional application in detecting DA, BPA, CT and HQ.

A multifunctional solid-state electrochemiluminescence (ECL) sensing platform based on poly(ethylenimine) (PEI) capped N-doped carbon dots (NCDs@PEI) as novel co-reactant of Ru(bpy)32+ nanosheets (RuNSs) was designed for the first time. In this route, RuNSs with large surface-to-volume ratio was used as luminophor, and NCDs@PEI, which was newly synthesized and modified in one step via a facile microwave-assisted method, was served as co-reactant. The as-prepared NCDs@PEI exhibited better catalytic effect to RuNSs than naked NCDs, due to the double enhancement contribution of NCDs and PEI to RuNSs. Simultaneously, reduced graphene oxide (rGO) was further introduced to facilitate the electron transfer and amplify the ECL signal. The developed ECL sensor (NCDs@PEI-rGO/RuNSs/GCE) exhibited desired ECL emission, with about 69-fold enhancement of the ECL intensity in comparison with RuNSs/GCE. When used as ECL probe for dopamine detection, the prepared sensor showed high sensitivity in a wide linear range of 0.01-50 μM with the detection limit of 10 nM. Moreover, the sensing platform also suggested multifunctional application for detecting other compounds including bisphenol A, catechol and hydroquinone.