Printed electronic (PE) devices that sense and communicate data will become ubiquitous as the Internet of things continues to grow. Devices that are low cost and disposable will revolutionize areas such as smart packaging, but a major challenge in this field is the reliance on plastic substrates such as polyethylene terephthalate. Plastics discarded in landfills degrade to form micro- and nanoplastics that are hazardous to humans, animals, and aquatic systems. Replacing plastics with paper substrates is a greener approach due to the biodegradability, recyclability, low cost, and compatibility with roll-to-roll printing. However, the porous microstructure of paper promotes the wicking of functional inks, which adversely affects printability and electrical performance. Furthermore, truly sustainable PE must support the separation of electronic materials, particularly metallic inks, from the paper substrate at the end of life. This important step is necessary to avoid contamination of recycled paper and/or waste streams and enable the recovery of electronic materials. Here, we describe the use of shellac—a green and sustainable material—as a multifunctional component of green, paper-based PE. Shellac is a cost-effective biopolymer widely used as a protective coating due to its beneficial properties (hardness, UV resistance, and high moisture- and gas-barrier properties); nonetheless, shellac has not been significantly explored in PE. We show that shellac has great potential in green PE by using it to coat paper substrates to create planarized, printable surfaces. At the end of life, shellac acts as a sacrificial layer. Immersing the printed device in methanol dissolves the shellac layer, enabling the separation of PE materials from the paper substrate.

Foldable displays have become increasingly used as a solution to the portability-practicality trade-off. A new scan driver integrated with metal oxide thin film transistors (MO TFTs) is proposed for foldable displays to overcome the effects of threshold voltage shifts on the scan driver output. In the scan driver, a feedback section and two series to transistor structures are used to keep the voltage of the key node to sustain a normal output, with this structure, the lower the voltage of the negative supply, the more stable the scan driver will be. Some flexible MO TFTs and 60 stage scan drivers are fabricated by etch stop layer structures on the polyimide substrate. Under different strains and 100 000 times bending with the minimum 3.5 mm bending radius, the characteristics of MO TFTs and the output waveform of the scan driver are measured. Experimental results show that the proposed scan driver shows high reliability since only a little voltage fluctuation occurs at the outputs after the bending test and has a better output waveform with a lower voltage of the negative supply.

Metal-based materials, such as silver or copper, are highly desired as current collector materials for flexible energy storage due to their excellent electrical properties but lack the long-term operational electrochemical stability. Herein we report a method to prevent the corrosion of such materials, while fully exploiting their electrical properties. This was achieved by covering the current collector with an electrochemically stable conductive carbon-based layer. The barrier layer allows the flow of charge between the electrically conductive elements of the textile composite electrodes, while protecting the current collector from contacting the electrolyte. The areal power and energy densities obtained after 1000 bending cycles were 29.88 and 0.01 mWh cm−2, respectively, with no evident degradation. Additionally, patterned current collectors were designed to deposit lower quantities of ink, without detriment to electrochemical performance. After 1000 bending cycles, the textile composite supercapacitors (TCSs) having 50% less current collector material demonstrated an areal power and energy density of 28.08 and 0.01 mWh cm−2, respectively. The proposed strategy is essential in enabling the utilisation of highly conductive metal-based inks, improving the rate capabilities and long-term operation of wearable energy storage devices, while maximising specific power and energy densities of TCSs, and decreasing the manufacturing cost.

The substrate plays an important role in flexible devices and sensors. In this direction, it is observed that elastomeric encapsulation assists the sensor system to deform successfully under stretching. The encapsulation not only makes it flexible but also protects it from environmental factors and mechanical damage. In this paper, a finite element method analysis is used to study the mechanical effects on the encapsulated system, which provides insight into the design of a stretchable substrate for flexible electronic systems. Here, a serpentine silver electrode is designed on a polyethylene terephthalate substrate, which is then encapsulated by polydimethylsiloxane. With the variation in the ratio of top-to-bottom encapsulation thickness i.e. T en1: T en2, the interfacial stress was studied. The mismatch in T en1 and T en2 may result in compressive bending strain, which can be avoided by making T en1 = T en2. It is observed from the simulation that, there is a spike in von-Mises stress at the interface of the substrate and the encapsulation when stretching mode deformation is applied. Also, this maximum stress varies with the variation in encapsulation thickness. For a range of total encapsulation thickness i.e. T EN = T en1 + T en2 = 30 μm to 100 μm, the optimum thickness is found to be 55 μm, for which the spike in interfacial von-Mises stress is minimum.

Polythiophenes comprise a class of emerging materials with potential applications in the field of temperature sensing. In this article, we validate and apply an integrated blending and printing methodology to combinatorially study libraries of pristine and compositionally graded blends of polythiophenes PEDOT:PSS and P(S-EDOT) (a PEDOT-like self-doped conjugated polymer) to understand their intrinsic electrical conductivity behaviour and along with its temperature dependence on blend composition and ambient temperature. Hypothesis testing is conducted to identify optima in electrical conductivity from combinations of input material proportions intended to meet multiple requirements otherwise difficult to achieve in any single-component solution-processable material. We chose PEDOT:PSS as a commercial developed intrinsically conductive polythiophene and with it, compared a novel self-doped polythiophene P(S-EDOT) as its potential replacement or complement as a sensor material. The electrical and morphological characteristics for both polymers and their blends were investigated for use as different components of temperature sensing applications. Different error sources within the process flow were considered for statistically significant conclusions regarding the utility of different compositions for different aspects of temperature sensing.

Burring is commonly encountered upon patterning of dielectric-metal-dielectric (DMD) transparent electrodes by laser ablation. These burrs are conductive and thus lead to shunting of the (opto-)electronic devices built upon these electrodes. In this work, CO2 snow jet blasting is presented as a convenient and reliable method for deburring laser-patterned DMD electrodes during roll-to-roll manufacturing of organic solar modules. As CO2 snow jet blasting significantly reduces the extent of shunting and concomitantly avoids scratching the electrode, the photoelectrical conversion efficiencies of the solar modules thus produced are higher than those obtained for traditional deburring techniques.

Rapid fabrication of flexible electronics is attracting much attention in many industries. There is a need to rapidly produce flexible electronic components without relying on costly precursor materials and complex processes. This work presents a direct laser writing (DLW) process capable of rapidly depositing flexible copper or copper oxide structures with a high degree of control over electrical properties. The DLW process uses a low-power fiber laser beam to selectively irradiate a thin film of copper ions to form and interconnect copper nanoparticles. The electrical properties of the deposited patterns can be controlled by tuning laser power, scanning speed, and beam defocus. The microstructures of patterns printed at varying laser powers are investigated using scanning electron microscopy, x-ray photoelectron spectroscopy, and x-ray powder diffraction and the relation between laser power and sheet resistance is explored. The results showed that high laser energy densities resulted in highly conductive patterns of metallic copper, whereas lower energy patterns resulted in copper oxide-rich patterns with significantly lower conductivity. This method can produce high-quality flexible electronic components with a range of potential applications, as demonstrated by the proof-of-concept fabrication of a flexible memristive junction with resistive switching observed at ±0.7 V and a R on/R off ratio of 102.

Stretchable printed electronics have recently opened up new opportunities and applications, including soft robotics, electronic skins, human-machine interfaces, and healthcare monitoring. Stretchable hybrid systems (SHS) leverage the benefits of low-cost fabrication of printed electronics with high-performance silicon technologies. However, direct integration of silicon-based devices on conventional stretchable substrates such as thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS) is extremely challenging due to their restricted low-temperature processing. In this study, a recently developed thermoset, stretchable substrate (BeyolexTM) with superior thermal and mechanical properties was employed to realize SHS via direct flip chip bonding. Here, ultra-thin chips (UTC) with a fine-pitch, daisy-chain structure was flip-chip bonded by using anisotropic conductive adhesives, while the complementary circuitry was facilitated via screen-printed, stretchable silver tracks. The bonded samples successfully passed reliability assessments after being subjected to cyclic 30% stretch tests for 200 cycles. The potential benefits of chip encapsulation after integration with the stretchable substrate to withstand larger strains were demonstrated by both mechanical simulation and experimental results.

In recent years, inkjet printing has been widely used in the field of flexible sensor preparation. However, the effects of inkjet printing parameters and post-processing conditions on sensor performance have not been systematically investigated. Simple fabrication and optimized performance are eagerly desired for the practical use of temperature sensors in wearable healthcare devices. Herein, we report the resistive flexible temperature sensor fabricated on polyethylene terephthalate (PET) substrates with silver nanoparticles (AgNPs)-based ink using an inkjet printer. We have thoroughly investigated and optimized the sensitivity and linearity between the resistance and temperature of inkjet-printed temperature sensors by adjusting droplet spacing and curing conditions (temperature and time). In conclusion, the droplet spacing of 20 µm and the curing condition of 30 min at 150 °C were determined as the optimized parameters. With optimized process parameters, the temperature sensor has a high sensitivity of 0.084 °C−1 and a linear coefficient of 0.999 between relative resistance and temperature in the range of 30 °C–100 °C. Furthermore, it has a fast response time (7 s) and high stability against repeated bending deformation of 500 cycles. The prepared wearable sensors have potential application prospects in temperature monitoring.

The electrical performance of stretchable electronic inks degrades as they undergo cyclic deformation during use, posing a major challenge to their reliability. The experimental characterization of ink fatigue behavior can be a time-consuming process, and models allowing accurate resistance evolution and life estimates are needed. Here, a model is proposed for determining the electrical resistance evolution during cyclic loading of a screen-printed composite conductive ink. The model relies on two input specimen-characteristic curves, assumes a constant rate of normalized resistance increase for a given strain amplitude, and incorporates the effects of both mean strain and strain amplitude. The model predicts the normalized resistance evolution of a cyclic test with reasonable accuracy. The mean strain effects are secondary compared to strain amplitude, except for large strain amplitudes (>10%) and mean strains (>30%). A trace width effect is found for the fatigue behavior of 1 mm vs 2 mm wide specimens. The input specimen-characteristic curves are trace-width dependent, and the model predicts a decrease in N f by a factor of up to 2 for the narrower trace width, in agreement with the experimental results. Two different methods are investigated to generate the rate of normalized resistance increase curves: uninterrupted fatigue tests (requiring ∼6–7 cyclic tests), and a single interrupted cyclic test (requiring only one specimen tested at progressively higher strain amplitude values). The results suggest that the initial decrease in normalized resistance rate only occurs for specimens with no prior loading. The minimum-rate curve is therefore recommended for more accurate fatigue estimates.

Electromigration (EM) is crucial to the reliability of most conductive lines used in electronics. In the present study, the EM characteristics of inkjet-printed Ag conductive lines were analyzed under various EM acceleration conditions to comprehend the EM failure behaviors associated with inkjet-printed Ag lines with nanoparticle inks. The evolution of the porosity level in the microstructure of the inkjet-printed Ag lines during the EM test was investigated to locate the EM failure positions in the line and identify the main driving force for EM mass transport. Two theoretical models (resistometric and Black’s) were employed to analyze the activation energy and expected lifetime of inkjet-printed Ag lines. This study indicates that the EM of Ag cations is directed toward the cathode by the direct force resulting from the electric field–ion interaction, resulting in EM failure near the anode and hillock formation near the cathode of the inkjet-printed Ag lines. The activation energy computed from the theoretical models suggests that the surface diffusion of Ag through the inkjet-printed line plays an important part in the EM failure mechanism. This research was a pioneering attempt to experimentally investigate the EM performance of inkjet-printed Ag lines.

Novel printed electronics are projected to grow and be manufactured in the future in large volumes. In many applications, printed electronics are envisaged as sustainable alternatives to conventional (PCB-based) electronics. One such application is in the semi-quantitative drug detection and point-of-care device called ‘GREENSENSE’ that uses paper-based printed electronics. This paper analyses the carbon footprint of GREENSENSE in order to identify and suggest means of mitigating disproportionately high environmental impacts, labeled ‘sustainability hotspots’, from materials and processes used during production which would be relevant in high-volume applications. Firstly, a life cycle model traces the flow of raw materials (such as paper, CNCs, and nanosilver) through the three ‘umbrella’ processes (circuit printing, component mounting, and biofunctionalization) manufacturing different electronic components (the substrate, conductive inks, energy sources, display, etc) that are further assembled into GREENSENSE. Based on the life cycle model, life cycle inventories are modeled that map out the network of material and energy flow throughout the production of GREENSENSE. Finally, from the environmental impact and sustainability hotspot analysis, both crystalline nanocellulose and nanosilver were found to create material hotspots and they should be replaced in favor of lower-impact materials. Process hotspots are created by manual, lab-, and pilot-scale processes with unoptimized material consumption, energy use, and waste generation; automated and industrial-scale manufacturing can mitigate such process hotspots.

Joule heating textiles are available on the market for a variety of applications. However, their market growth is limited by challenges in terms of quality, for instance with the need to provide a reliable account of the heating to be expected, prevent the occurrence of overheating leading to burns and fires, and ensure the long-term performance when exposed to use conditions such as abrasion and laundering. Standard test methods are a key component to solve these issues of efficiency, safety, and durability. Yet, they mostly remain to be established. In this research, a test method was developed for the characterization of the Joule heating efficiency of electric textiles. It involves measuring the temperature of a heating textile using a thermocouple affixed to its surface while it is powered for an hour. The value of the surface temperature that would ultimately be reached by the heating textile after an infinite heating time and the time for the temperature to enter a slow increase regime are determined by fitting an equation to the temperature-time data. These two parameters provide a quantitative mean of comparison between different heating textiles/conditions. This test method was used to analyze the effect of different experimental conditions on the heating efficiency of four heaters corresponding to different technologies of Joule heating textiles and make recommendations in terms of conditions for a standardized test protocol. These results give some insights towards the development of a robust and universal test method for the quantitative assessment of the Joule heating efficiency of electrical textiles that will ultimately be proposed for standardization to help support the growth of the e-textile industry.

The ability to detect impact waves and their propagation across materials is the key to structural health monitoring and defect detection of materials. To detect impact waves from a certain type of structures, it is important for a sensor to be highly flexible and complex in shape. Direct ink write (DIW) allows for the manufacturing of complex sensors. This article presents the fabrication of a flexible impact wave propagation sensor (IWPS) through the DIW technique. The dispersion of a ferroelectric ceramic material barium titanate (BaTiO3, or BTO) in polydimethylsiloxane (PDMS), not only enhances the flexibility of the 3D (three-dimensional) printed sensor but also ensures the uniform piezoelectric response throughout the whole sensor. This research explored the impact load generated impact wave in the flexible sensor and sensing response. The capability of DIW for multi-material printing was utilized to print multi-walled carbon nanotube based electrodes on BTO/PDMS stretchable composites. A total of 50 wt% of BTO in the PDMS matrix resulted in a piezoelectric coefficient of 20 pC N−1 after contact poling of IWPS. Upon applying impact loading at the center of the sensor, an impact wave was generated which gradually diminished with the distance from the origin of the applied impact load. The impact wave propagation was quantitatively characterized by measuring output voltage from different nodes of IWPS. Additionally, from the voltage response time difference at different locations of the sensor, the particle-wave velocity of a certain material attached to IWPS was determined in this research. Using the custom-designed IWPS, it was found that the particle-wave velocity of stainless steel and low-density polyethylene were 5625 m s−1 and 2000 m s−1 respectively, which are consistent with their theoretical values.

The selection of materials and technologies for green printed electronics design is a fundamental and time-consuming task. This paper represents a rigorous experimental overview in which different printing technologies, ink formulations, and paper-based substrates are examined and analyzed. Three printing techniques are investigated: inkjet printing, screen printing, and direct ink writing. Regarding the inks, formulations based on carbon and silver have been chosen as conductive materials. Initially, the electrical properties of the selected inks have been characterized on a conventional substrate in printed electronics such as polyethylene terephthalate. Later, the printing conditions are optimized for various paper-based substrates, including commercial papers and substrates based on cellulose nanofibers (CNF). CNF are also used as a coating for commercial papers and their influence on the printing quality is evaluated. The substrates are also characterized in terms of morphology, wettability, and thermal stability. This study facilitates the benchmarking tasks for researchers developing new devices and contributes toward the eco-design of flexible green printed electronics.

In this research, we conducted a wear test on inkjet-printed silver conductors using different loads and counter materials (two paperboards, brushed steel sheet, and sandpaper) with similar surface roughness values. The conductor’s reliability was characterized by resistance measurement, the failures and tested counter materials were analyzed using an optical microscope, profilometer, scanning electron microscope, and energy dispersive spectrometer. It was found that the counter material has a dominant impact on a conductor’s reliability and failure mechanism compared with load. The conductors were exceptionally reliable but subject to adhesive wear when tested by paperboards. They were also highly reliable when tested by brushed steel sheet although the silver became severely detached, and the conductivity was lost suddenly when a major scratch was caused by two-body and three-body abrasive wear mechanisms. Sandpaper rubbing caused the most severe silver detachment and quick loss of conductivity, as a large amount of small-size (5–15 µm) silicon carbide particles with sharp edges and corners caused a dense cutting effect via two-body abrasive wear (by cutting) mechanism. Additionally, the failures in almost all samples occurred in the areas in contact with the counter edges, suggesting that failure was accelerated by the edge effect. This study proves that inkjet-printed electronics on the investigated paperboard is exceptionally durable when rubbed by paperboards and steel sheets, and thus provides a reliable solution to intelligent packaging. To promote intelligent packaging, more paperboards, as well as approaches for reducing the edge effect can be investigated.

Besides the metal oxide thin film transistors (TFTs) in flat-panel displays that are fabricated using vacuum-processes, there is a growing interest in the fabrication of metal oxide TFTs by means of scalable, low-cost solution and printing processes for applications such as flexible displays and biosensors. Although devices with printed semiconductor and gate insulator can exhibit good electrical performance, source/drain-contacts (S/D) printed from silver (Ag) nanoparticles (NPs) typically suffer from deteriorated electrical characteristics and stability problems. On the other hand, metals providing good contacts, such as aluminum (Al), titanium (Ti) and molybdenum (Mo), cannot be formed as air-stable NPs. To overcome these issues, we have developed a patterning method based on high-resolution reverse-offset printing (ROP) of a sacrificial polymer resist layer. ROP delivers patterns with micrometer-level resolution and steep sidewalls, which are ideal for patterning vacuum-deposited metal contacts at high resolution via lift-off process. Solution-processed indium oxide (In2O3) TFTs were successfully fabricated by using ROP lift-off process for patterning of gate and S/D-electrodes using Al. The fabricated In2O3-based TFTs with Al S/D-contacts exhibit good uniformity, constant mobility (μ sat) ∼ 2 cm2 (V s)−1 over a wide range of width/length-ratios (W/L) and almost zero turn-on voltage (V on) ∼ −0.2 V. TFTs down to 5 µm channel lengths were successfully patterned. Further development of the fabrication process could lead to flexible fully-print-patterned high-resolution TFT backplanes for flexible displays, biosensors, photosensors and x-ray detectors.

The proliferation of electronic devices has made electromagnetic interference (EMI) shielding an exponentially growing business. Regulatory requirements change constantly as new technologies continue to emerge. Innovations in materials and new advances in shielding implementation techniques are needed to pass regulatory compliance tests at an affordable cost. Here, we print various EMI shielding materials such as copper, silver and a composite of copper with Fe3O4 using plasma jet printing. Printing enables shields only a few microns thick capable of high shielding effectiveness. Copper’s EMI shielding performance is primarily contributed by reflection mechanism, as expected and this is known to cause secondary pollution. A Green Index for EMI shielding, given by the ratio of absorption and reflection contributions to shielding, indicates values lower than 0.1 for printed copper films.

Nanocomposites formed by silver nanowires (AgNWs) embedded in a polymer matrix are a convenient way to deposit thin films with electrical conductance and high transparency on different substrates. Nanocomposite resists containing AgNWs in a poly(methyl methacrylate) solution can be effectively used to produce conductive coatings in a straightforward manner. Here, we show that by adding a sacrificial layer of polyvinylpyrrolidone on a glass substrate, prior to the nanocomposite resist, it is possible to obtain large-area free-standing films of about 450 nm with electrical conductance and high transparency. The films can be transferred to different surfaces and materials including non-flat substrates. The formation of conductive stacks by piling two layers was also demonstrated. The optical, electrical, and structural properties of these free-standing films were studied obtaining films with transmittance T(%) = 78% at 550 nm, sheet resistance Rs = (670 ± 40) Ω sq−1 and surface roughness Ra = (50 ± 10) nm. We studied the strain resistance behavior of films transferred to polyethylene terephthalate sheets under bending tests finding a sensitivity of (0.51 ± 0.01) Ω deg−1 and a gradual increase in the resistance during cycling. In addition, thin flexible supports can be added by covering the nanocomposite film with polydimethylsiloxane (PDMS) prior to its release, enhancing the mechanical robustness and improving the manipulation of the films.

Previously, we developed several carbamate side chain-substituted hemi-isoindigo (HID)-based π-conjugated polymers, which demonstrated excellent sensitivity and stability as the sensing layers in chemiresistive temperature sensors. This work investigated the effects of the side chains on the HID units by changing the carbamate to alkyl side chains. Specifically, a series of 2-ethylhexyl-substituted HID polymers, poly(3-((3'',4'-bis(dodecyloxy)-[2,2':5',2''-terthiophen]-5-yl) methylene)-1-(2-ethylhexyl)indolin-2-one-6,5”-diyl) (PTAB), poly(3-((3'',4'-bis(dodecyloxy)-3,4-dimethoxy-[2,2':5',2''-terthiophen]-5-yl) methylene)-1-(2-ethylhexyl)indolin-2-one-6,5”-diyl) (PMAB), and poly(3-((7-(3,3'-bis(dodecyloxy)-[2,2'-bithiophen]-5-yl)-2,3-dihydrothieno[3,4-b] [1,4]dioxin-5-yl)methylene)-1-(2-ethylhexyl)indolin-2-one-6,5”-diyl) (PEAB) were synthesized, and their properties and temperature sensing performance were compared with their counterpart carbamate-substituted HID polymers, poly(2-ethylhexyl-3-((3'',4'-bis(dodecyloxy)-[2,2':5',2''-terthiophen]-5-yl)methylene)-2-oxoindoline-1-carboxylate-6,5”-diyl) (PTEB), poly(2-ethylhexyl-3-((3'',4'-bis(dodecyloxy)-3,4-dimethoxy-[2,2':5',2''-terthiophen]-5-yl)methylene)-2-oxoindoline-1-carboxylate-6,5”-diyl) (PMEB), and poly(2-ethylhexyl-3-((7-(3,3'-bis(dodecyloxy)-[2,2'-bithiophen]-5-yl)-2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)methylene)-2-oxoindoline-1-carboxylate-6,5”-diyl) (PEEB), and their thermally annealed products, poly(3-((3'',4'-bis(dodecyloxy)-[2,2':5',2''-terthiophen]-5-yl)methylene)indolin-2-one-6,5”-diyl) (PTNB), poly(3-((3'',4'-bis(dodecyloxy)-3,4-dimethoxy-[2,2':5',2''-terthiophen]-5-yl)methylene)indolin-2-one-6,5”-diyl) (PMNB), and poly(3-((7-(3,3'-bis(dodecyloxy)-[2,2'-bithiophen]-5-yl)-2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)methylene)indolin-2-one-6,5”-diyl) (PENB). The highest occupied molecular orbital energy (E HOMO) level and crystallinity of PEAB are very similar compared to PEEB. Chemiresistor devices with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) (PEAB:F4TCNQ) fabricated on flexible plastic substrates exhibited a high temperature coefficient of resistance (TCR) of −1.09% °C−1, although the value is lower than that (−1.92% °C−1) of the device based on PENB:F4TCNQ. The device based on PEAB:F4TCNQ also showed excellent stability with no performance degradation over 1 month, which is similar to the device based on PENB:F4TCNQ. On the other hand, PTAB and PMAB showed significantly higher E HOMO levels and crystallinity compared to their counterpart polymers. Sensors based on PTAB:F4TCNQ and PMAB:F4TCNQ showed TCR values of −1.02% °C−1 and −1.15% °C−1, respectively, which are lower than their corresponding annealed carbamate-substituted HID polymers. PTAB has a much lower E HOMO level (−4.95 eV) than that of PTNB (−4.69 eV) and is more crystalline than the latter, which should lead to poorer stability of the doped complex PTAB:F4TCNQ. Surprisingly, PTAB:F4TCNQ showed much better long-term stability than PTNB:F4TCNQ. It was considered that the hydrophobic alkyl side chains in PTAB can help prevent the interaction of water in the air with the PTAB:F4TCNQ complex, thereby stabilizing the complex. This study provided new insights into the design principles of conjugated polymers for printed and flexible temperature sensors.