Printing assembly of flexible devices with oxidation stable MXene for high performance humidity sensing applications

• Published in: Sensors and actuators. B, Chemical Chemical, 2022-08, Vol.364, p.131867, Article 131867
• Main Authors: Yang, Meng-yao, Huang, Meng-lin, Li, Yun-ze, Feng, Zhe-sheng, Huang, Yan, Chen, Hai-jun, Xu, Zhao-quan, Liu, Hui-gen, Wang, Yan
• Format: Article
• Language: English
• Subjects: Humidity sensor; Minimally intensive layer delamination (MILD); MXene; Oxidation resistance; Sodium ascorbate; Ti3C2Tx
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2022.131867

Transition metal carbides and carbonitrides MXenes have developed to be attractive nanomaterials for humidity-sensitive materials due to abundant hydrophilic active sites on their chemically active surfaces. Nevertheless, the low stability exhibited by MXenes in moist air or water limits their long-term storage and wide applications. This work proposes a composite of sodium ascorbate-decorated MXene (SA-MXene) by combining ascorbate ions with Ti3C2Tx MXene synthesized through a minimally intensive layer delamination (MILD) process. The synthesizing and decoration of MXene with SA to obtain SA-MXene had been shown to be a viable method for avoiding Ti3C2Tx MXene materials from oxidizing. The as-prepared SA-MXene was formulated as screen-printing ink with high stability and oxidation resistance despite being stored at ambient temperature after 30 days. Furthermore, a flexible humidity sensor was assembled by screen-printing technology with SA-MXene ink as the humidity-sensitive layer on the copper interdigital electrode prepared by the electrodeless deposition (ELD) process. Consequently, the SA-MXene sensor showed remarkable potential in humidity sensing with an ultrahigh relative capacitance response (131.4% to 97% RH) and rapid response time across a wide detection range. This work represents a promising strategy of developing SA-MXene to fabricate high sensitivity sensors derived from MXene. The synthesizing and decoration of MXene with SA to obtain SA-MXene had been proven to be a viable method for avoiding Ti3C2Tx MXene materials from oxidizing in this work, and the SA-MXene was formulated as screen-printing ink with high stability and oxidation resistance despite being stored at ambient temperature after 30 days. Furthermore, the proposed flexible SA-MXene sensor assembled by printing showed remarkable potential in humidity sensing with an ultrahigh relative capacitance sensitivity (131.4% to 97% RH) and rapid response across a wide detection range. [Display omitted] •The oxidation of Ti3C2Tx MXene was prevented by sodium ascorbate effectively.•Sodium ascorbate-decorated MXene realized the assembly of flexible device printing.•Proposed humidity sensor showed ultrahigh capacitance sensitivity (131.4% to 97% RH).