# Filter, Flip, and Fabricate: A Wax-Assisted Stamp-Transfer Approach for Flexible Ti3C2T x MXene Electrochemical Transducers

## TL;DR

This paper introduces a new wax-assisted method to create flexible MXene-based electrochemical sensors with high reproducibility and performance.

## Contribution

A novel wax-assisted stamp-transfer (WAST) method for fabricating MXene electrochemical transducers with flexible configurations.

## Key findings

- WAST method produced MXene transducers with consistent anodic and cathodic peak currents and low peak separation.
- Configuration B showed a 3-fold lower peak separation compared to configuration A, indicating improved performance.
- The method successfully mimicked commercial electrode performance and demonstrated Hg2+ ion sensing capability.

## Abstract

Combining additive-free solution processing of MXenes
with template-assisted
transfer represents an innovative approach for the fabrication of
electrochemical sensors. Herein, we introduce a wax-assisted templating
and stamp-transfer (WAST) approach to fabricate monolithic
MXene transducers. To this end, two configurations were developed:
(A) MXene-at-all electrodes, where the working, counter,
and reference electrodes were entirely composed of MXene, and (B)
MXene working electrodes combined with an Ag/AgCl pseudoreference
and carbon counter electrodes. Additive-free MXene inks, at different
concentrations and volumes, were filtered onto wax-templated PVDF
membranes to form stampable patterns. Voltammetric characterization
revealed consistent anodic and cathodic peak currents (I
pa and I
pc) and steady peak-to-peak
separation (ΔE
p) across three independent batches, indicating excellent reproducibility
with I
pa = 87.9 ± 1.7 μA, I
pc = −81.3 ± 1.5 μA, and ΔE
p = 255.9 ± 4.6 mV for configuration A,
and I
pa = 43.8 ± 0.6 μA, I
pc
= −62.8 ± 1.2
μA, with a 3-fold lower peak separation (ΔE
p = 87.6 ± 0.9 mV) in the case of configuration B
(mean ± SE, n = 15). Primary benchmarking with
similar commercial systems signifies the efficacy of WAST-produced transducers to mimic commercial electrode performance and
provides a robust alternative to conventional deposition methods.
In addition, a proof-of-concept experiment for Hg2+ ion
sensing validated its potential for practical applications. The WAST method offers a robust fabrication, configuration choice,
and tool-light patterning that can accelerate lab-scale prototyping
of stand-alone flexible electrochemical devices.