Nanoporous naphthalene diimide surface enhances humidity and ammonia sensing at room temperature
Graphical Abstract
Introduction
Porous materials with micro- to nano-dimensional pore sizes, and subsequently high surface areas, are essential for manufacturing, scientific, and domestic applications where an adsorption mechanism is favoured. Long recognised and extensively employed porous inorganic materials such as, alumina, fumed silica, zeolites, or activated charcoals have inspired the development of novel materials with definite pore sizes, high surface areas and functionalities [1], [2]. Over the past few years, highly engineered organic-inorganic composites and organic porous materials have also emerged and are currently being studied with the hope that they can compete with their inorganic equivalents in a variety of applications [3], [4], [5]. Nanoporous materials have found use in an array of applications such as energy and gas storage [6], [7], solar cells [8], catalysis [9] and sensors [10], mainly due to their distinctive physical and chemical properties including high surface area [11]. Such materials provide promise in chemical and biological sensing because they offer tunable pore/void space and large surface area, which offer enrichment of the adsorbate effects and high activity in surface chemical interactions. Studies have shown that the electrical and optical properties of porous semiconductors may vary substantially upon adsorption of molecules to their surfaces and/or by filling the pores. Therefore, surface adsorption and capillary condensation effects in nanoporous materials can be applied in the preparation of efficient sensor systems [12], [13], [14].
Among the variety of chemical and biological sensors, simple humidity sensors are applied to monitor relative humidity (RH) and have become crucial for weather prediction, historic preservation, environmental studies, semiconductors, agriculture applications, food processing, pharmaceutical preparations, textiles, paper, medicinal apparatus’s, and heating, as well as ventilation and air-conditioning [15], [16], [17], [18]. Various materials, including small organic molecules, organic polymers, graphene, and inorganic composite materials, have been employed for humidity sensing applications with various effects [19], [20], [21], [22], [23], [24]. However, water vapour isn’t the only potential use for such sensors. Considering environmental pollution factors, it is critical to identify and measure the precise concentration of hazardous gases such as ammonia, which has extensive applications in fertilisers, synthetic fibres, drugs, generating ammonium salts, and the manufacturing of plastics [25]. Ammonia is a highly corrosive and poisonous gas that can be easily propagate into the ecosystem [26], [27]. Prolonged exposure can lead to severe health effects from airway swelling or damage through burning. In high concentrations, it can be lethal. While the lower limit of human sensitivity by smell is about 50 ppm for ammonia [28], even at this limit, it is irritating to the skin, eyes, and the respiratory system, leading to cough and nose/throat irritation [29]. The permissible thresholds of 25 ppm over 8 h and 35 ppm over 10 min periods have been recommended and legislated by Health and Safety Executive (HSE), London [30].
Commercially available sensors for humidity and ammonia detection are usually based on porous metallic oxide materials, like ZnO, SnO2, WO3 and Fe2O3 [31], [32], [33]. However, the sensors based on these materials have certain drawbacks such as high working temperature, low selectivity, and the solid substrate brittleness limit their suitability in wearable electronics [34], [35]. Polymers, graphene and organic semiconductor-based sensors which can surmount these existing weaknesses are considered as favourable candidates [36], [37]. Currently, small organic molecules, including phthalocyanines (Pcs), perylene diimides (PDIs), and naphthalene diimides (NDIs), have gained significant attention in various humidity and gas sensing applications [24], [27], [38]. Small organic molecules should provide benefits such as easy synthetic methods, defined molecular formula, definite molecular weight, simple purification and structural modification, good batch-to-batch reproducibility, good solubility and film formability. Furthermore, their structural, electrical, and surface properties should be easily tuned by molecular engineering [39], [40]. NDIs also possess good chemical and thermal properties, exceptional charge mobility, simple synthetic procedures, and solution processability among small organic molecules. However, they are rarely investigated for humidity and ammonia sensing applications, and those which are reported are in organic field-effect transistor (OFET) platforms [41], [42]. The OFET based sensors do exhibit good sensitivity, but they have complex fabrication techniques and are prone to device shorting. In contrast, capacitive/amperometric type sensors would provide straightforward, low-cost, and easy to fabricate alternatives, if developed. To this end, we recently studied three NDI derivatives carrying imide side chains of various hydrophilicity for capacitive humidity sensing [24]. The results revealed that different hydrophilic groups on the imide position affect the surface morphology and crystalline structure and indeed interacted differently with water molecules, thereby providing an impact on sensing performance of the humidity sensors.
In this current work, we report on the assembly of nanoporous films of NDI-1 (Fig. 1a) and apply these surfaces to humidity and ammonia sensing applications employing capacitive and amperometric platforms at ambient temperature. There are no examples in the current literature where a simple, NDI-based small molecule is reported to create nanoporous surface and is used to enhance humidity and ammonia gas sensing at room temperature. The idea of generating film porosity to improve gas sensing is an active area of research and to the best of our knowledge, this is the first report of an NDI derivative being used in an amperometric type sensor for ammonia sensing. Several sensing parameters such as sensitivity, response/recovery, hysteresis, non-contact humidity sensing performance, breath analysis, stability, recyclability and selectivity of NDI-1 have been evaluated in detail at room temperature (RT).
Section snippets
Synthesis
The one-step synthetic protocol used for NDI-1 in which both imidation and esterification reactions occur concurrently is given in the Supplementary information (SI).
Thin film sensor fabrication
Silicon (Si) substrates and interdigitated electrodes (IDEs) (10 mm × 6 mm × 0.75 mm dimensions with 10 µm spacing between the fingers) were utilised in the preparation of thin films and sensors (Fig. 1b), respectively. The IDEs were acquired commercially from Micrux technologies and consist of a quartz (SiO2) substrate patterned
Thin film and material characterisations
An image of a thin film of NDI-1 via AFM (Fig. 2a) revealed the effective pattern of nanopores, which were uniformly distributed over the whole surface. The pores vary slightly in their size distribution (200–400 nm), though are remarkably regular. The distribution of these nanopores over the surface were thought to provide a scientific advantage to our previous work [24] by assisting the adsorption, or capture, of target water, for instance, ensuring better sensing performance. The inherent
Conclusions
We were able to successfully develop a prototypical sensor that is highly sensitive to humidity and ammonia at room temperature via employing an NDI-1 active layer. The AFM and SEM analysis revealed a uniform nanoporous structure of a thin film of NDI-1, which we believe attributed to the properties exhibited. The humidity sensing properties of the prepared sensor was studied by exposing it to various humidity levels ranging from 0% to 95% at RT, and the sensor displayed swift response and
CRediT authorship contribution statement
Salman Ali: Conceptualisation, investigation, materials and devices fabrication and characterisations, and writing the original draft. Mohammed A. Jameel: TGA and DSC measurements and assisted in data interpretation. Christopher J. Harrison: Assistance in sensing data collection and writing. Akhil Gupta: Materials synthesis, assisting in data interpretation and writing. Steven J. Lanford and Mahnaz Shafiei: Results analysis, reviewing and finalising the draft, Supervising, Funding and managing
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This research received funding from the Australian Renewable Energy Agency (ARENA) as part of ARENA's Research and Development Program-Renewable Hydrogen for Export (Contract No. 2018/RND012). The views expressed herein are not necessarily the views of the Australian Government, and the Australian Government does not accept responsibility for any information or advice contained herein. This research was supported by using the Nectar Research Cloud, a collaborative Australian research platform
Salman Ali is an organic electronic devices researcher at the School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Australia. He has completed his MS (Physics) degree from Riphah International University, Islamabad, Pakistan. Presently, he is working on the application of Naphthalene diimides and various other small organic molecules for humidity and gas sensing applications. He is currently doing PhD at the Swinburne University of
References (69)
- et al.
Conjugated microporous polymers for energy storage: recent progress and challenges
Nano Energy
(2021) - et al.
Nanoporous materials derived from metal-organic framework for supercapacitor application
J. Energy Storage
(2020) - et al.
Construction of novel Pd–SnO2 composite nanoporous structure as a high-response sensor for methane gas
J. Alloy. Compd.
(2020) - et al.
Nanoporous platinum–cobalt alloy for electrochemical sensing for ethanol, hydrogen peroxide, and glucose
Anal. Chim. Acta
(2013) - et al.
Seed-mediated synthesis of copper nanoparticles on carbon nanotubes and their application in nonenzymatic glucose biosensors
Anal. Chim. Acta
(2012) - et al.
Humidity: a review and primer on atmospheric moisture and human health
Environ. Res.
(2016) - et al.
Effect of humidity during manufacturing on the interfacial strength of non-pre-dried flax fibre/unsaturated polyester composites
Compos. Pt A-Appl. Sci. Manuf.
(2016) - et al.
Humidity, light and temperature dependent characteristics of Au/N-BuHHPDI/Au surface type multifunctional sensor
Sens. Actuators B
(2014) - et al.
Humidity sensor based on ultrathin polyaniline film deposited using layer-by-layer nano-assembly
Sens. Actuators B
(2006) - et al.
Electrical characterization of PEDOT: PSS beyond humidity saturation
Sens. Actuators B
(2009)
Sensing performance of reduced graphene oxide-Fe doped WO3 hybrids to NO2 and humidity at room temperature
Appl. Surf. Sci.
Fabrication and characterization of an ultrasensitive humidity sensor based on metal oxide/graphene hybrid nanocomposite
Sens. Actuators B
Capacitive humidity sensing performance of naphthalene diimide derivatives at ambient temperature
Synth. Met.
Properties of humidity sensing ZnO nanorods-base sensor fabricated by screen-printing
Sens. Actuators B
Enhanced ammonia sensing performances of Pd-sensitized flowerlike ZnO nanostructure
Sens. Actuators B
Highly sensitive and selective gas sensors using p-type oxide semiconductors: Overview
Sens. Actuators B: Chem.
Highly sensitive OFET-based gas sensors using fluorinated naphthalenediimide semiconductor films
Synth. Met.
Sensing performance optimization by tuning surface morphology of organic (D-π-A) dye based humidity sensor
Sens. Actuators B
Evolution of breath analysis based on humidity and gas sensors: potential and challenges
Sens. Actuators B
Capacitive type humidity sensor based on PANI decorated Cu–ZnS porous microspheres
Talanta
A capacitive humidity sensor based on gold–PVA core–shell nanocomposites
Sens. Actuators B
Influence of thermal annealing on a capacitive humidity sensor based on newly synthesized macroporous PBObzT2
Sens. Actuators B
Bias and humidity effects on the ammonia sensing of perylene derivative/lutetium bisphthalocyanine MSDI heterojunctions
Sens. Actuators B
Highly sensitive and stable perylene sensor for ammonia detection: a case study of structure-property relationships
Sens. Actuators B
One-pot fabrication of uniform polypyrrole/Au nanocomposites and investigation for gas sensing
Sens. Actuators B
Mesoporous materials as gas sensors
Chem. Soc. Rev.
Macroscopically oriented porous materials with periodic ordered structures: from zeolites and metal–organic frameworks to liquid‐crystal‐templated mesoporous materials
Adv. Mater.
Advanced porous materials for sensing, capture and detoxification of organic pollutants toward water remediation
ACS Sustain. Chem. Eng.
The new age of MOFs and of their porous-related solids
Chem. Soc. Rev.
Nanoporous materials for the onboard storage of natural gas
Chem. Rev.
The preparation and properties of TiO2 nano-porous layers for perovskite solar cells
AIP Adv.
Recent advances in the textural characterization of hierarchically structured nanoporous materials
Chem. Soc. Rev.
Strategies for development of nanoporous materials with 2D building units
Chem. Soc. Rev.
Current trends in nanomaterials for metal oxide-based conductometric gas sensors: advantages and limitations. Part 1: 1D and 2D nanostructures
Nanomater
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Salman Ali is an organic electronic devices researcher at the School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Australia. He has completed his MS (Physics) degree from Riphah International University, Islamabad, Pakistan. Presently, he is working on the application of Naphthalene diimides and various other small organic molecules for humidity and gas sensing applications. He is currently doing PhD at the Swinburne University of Technology, Melbourne, Australia, under the supervision of Prof. Steven J. Langford and Dr. Mahnaz Shafiei and awarded Swinburne University Postgraduate Research Award (SUPRA) scholarship for his PhD studies.
Mohammed A. Jameel is a PhD researcher in the School of Science, department of Chemistry and Biotechnology at Swinburne University of Technology, Hawthorn, Australia. He studies material science. His doctoral project, supported by Swinburne University and CSIRO energy technologies, focus on designing, and Characterising Naphthalene Diimides as organic and perovskite solar cells. He received his master’s degree in science from University of Duhok, Kurdistan, Iraq, with the coordination of the University of Melbourne, Australia.
Christopher Harrison received his BE and BCompSci from RMIT University in 2013. He then transitioned to a PhD program developing novel digital signal processing techniques for application to acousto-electric sensors. He is currently engaged at Swinburne University of Technology as a research fellow, helping establish a gas sensing laboratory there. His work focuses on the development and application of novel sensing materials targeting the emerging hydrogen energy sector.
Akhil Gupta is currently working as a Research Fellow at the Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia. His research interests lie in the design and development of organic, inorganic and hybrid materials for a number of emerging research areas such as organic solar cells, self-assembly for light-harvesting, molecular gelation and chemical sensing. He completed his PhD at Monash University, Clayton Australia in 2013.
Mahnaz Shafiei is currently an Associate Professor and former Vice-Chancellor’s Women in STEM Fellow at Swinburne University of Technology and a visiting fellow at Queensland University of Technology (QUT). She received a Bachelor of Science degree in Electrical and Electronics Engineering from AmirKabir University of Technology in Iran, and a PhD degree from RMIT University, Melbourne, Australia in 2011. She followed this with postdoctoral research at QUT and an Australian Endeavour Research Fellowship at Simon Fraser University, Canada. Mahnaz’s research focus is on sensors and nanomaterials and their practical use for health and environmental monitoring. She is investigating new technologies to develop reliable, portable gas sensors with ultra-low power requirements to be embedded in sensor nodes for the Internet-of-Things applications or in mobile systems
Prof Steven Langford completed his PhD in 1994 from the University of Sydney and was the sole recipient of the Ramsay Memorial Trust Fellowship working with Prof Fraser Stoddart (2016 Chemistry Nobel Prize winner). After an ARC postdoc Fellowship at UNSW, he moved to Monash to begin his independent career in 1998, becoming Professor in 2006 and Head of School in 2010. After a distinguished career at Monash, he joined Swinburne in October 2017 as Dean, Research and Development. His interests involve the application of organic chemistry to new materials research, utilising the principles of supramolecular chemistry to areas as diverse as photosynthetic mimicry, sensors, sustainability, molecular electronics and medicinal chemistry.