A three dimensional nanowall of calcein/layered double hydroxide as an electrogenerated chemiluminescence sensor

Abstract

This paper reports the fabrication of a three-dimensional (3D) nanowall structure based on the intercalation of calcein into a layered double hydroxide (LDH) by a modified solvothermal direct growth process, and explores its electrogenerated chemiluminescence (ECL) property for detection of dopamine (DA). X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the calcein/LDH nanowall film possess a preferential orientation with their ab plane perpendicular to the substrate. The nanowall film shows tunable luminescence properties by simple changing the amount of calcein in the LDH interlayer, and the optimum fluorescence intensity occurs in the sample with x = 1.25%. The stable and strong ECL signals suggested that this film possesses excellent operational and storage stability, which is essential for a sensor. The ECL intensity increased linearly with increasing DA concentration from 5.00 × 10⁻⁷ to 1.01 × 10⁻⁴ M. The detection limit was 3.52 × 10⁻⁷ M. The mechanism of the ECL sensor indicates that the 3D micro-morphology of the calcein/LDH nanowall film has a positive influence on the electrochemical property due to its high surface area and reduced interface resistance. Therefore, this work not only provides a preparation method for a chromophore/LDH complex with a 3D micro/nanostructure, but also systematically probed the structure–property relationship of the calcein/LDH nanowall film. According to this strategy, advanced sensors and devices with outstanding optical and electrochemical properties can be achieved.