Flexible Electronic Systems Research Articles

Beyond Flexible: Unveiling the Next Era of Flexible Electronic Systems.

Flexible electronics are integral in numerous domains such as wearables, healthcare, physiological monitoring, human-machine interface, and environmental sensing, owing to their inherent flexibility, stretchability, lightweight construction, and low profile. These systems seamlessly conform to curvilinear surfaces, including skin, organs, plants, robots, and marine species, facilitating optimal contact. This capability enables flexible electronic systems to enhance or even supplant the utilization of cumbersome instrumentation across a broad range of monitoring and actuation tasks. Consequently, significant progress has been realized in the development of flexible electronic systems. This study begins by examining the key components of standalone flexible electronic systems-sensors, front-end circuitry, data management, power management and actuators. The next section explores different integration strategies for flexible electronic systems as well as their recent advancements. Flexible hybrid electronics, which is currently the most widely used strategy, is first reviewed to assess their characteristics and applications. Subsequently, transformational electronics, which achieves compact and high-density system integration by leveraging heterogeneous integration of bare-die components, is highlighted as the next era of flexible electronic systems. Finally, the study concludes by suggesting future research directions and outlining critical considerations and challenges for developing and miniaturizing fully integrated standalone flexible electronic systems.

Motion Sensing by a Highly Sensitive Nanogold Strain Sensor in a Biomimetic 3D Environment.

Recent advancements in flexible electronics have highlighted their potential in biomedical applications, primarily due to their human-friendly nature. This study introduces a new flexible electronic system designed for motion sensing in a biomimetic three-dimensional (3D) environment. The system features a self-healing gel matrix (chitosan-based hydrogel) that effectively mimics the dynamics of the extracellular matrix (ECM), and is integrated with a highly sensitive thin-film resistive strain sensor, which is fabricated by incorporating a cross-linked gold nanoparticle (GNP) thin film as the active conductive layer onto a biocompatible microphase-separated polyurethane (PU) substrate through a clean, rapid, and high-precision contact printing method. The GNP-PU strain sensor demonstrates high sensitivity (a gauge factor of ∼50), good stability, and waterproofing properties. The feasibility of detecting small motion was evaluated by sensing the beating of human induced pluripotent stem cell (hiPSC)-derived cardiomyocyte spheroids embedded in the gel matrix. The integration of these components exemplifies a proof-of-concept for using flexible electronics comprising self-healing hydrogel and thin-film nanogold in cardiac sensing and offers promising insights into the development of next-generation biomimetic flexible electronic devices.

The detection of acetone in exhaled breath using gas Pre-Concentrator by modified Metal-Organic framework nanoparticles

Volatile organic compounds (VOCs) from exhaled breath are promising indicators for the diagnostics of human health conditions. However, the composition of breath is rather complex, including water vapors and various tiny amounts of gases and biomarkers. Pre-concentrator plays a significant role in capturing and concentrating target gas in the gas mixture. In this work, the MIL-101 (Cr) nanoparticles are coated with polydimethylsiloxane (PDMS) through physical vapor deposition process to concentrate acetone under high humidity and room temperature. Experimentally, the newly developed material exhibits significant improvement in signal intensity that is 76.3 times greater than a commercial reference material under relative humility of 80 %. The detection range is also proven to be desirable (from 100 ppb to 2500 ppb), capturing the spectrum of acetone concentrations typically found in human exhaled breath. Moreover, following a thermal desorption process, the device demonstrates a high degree of linearity with a coefficient of 0.9956. The modified metal–organic framework materials are made into a flexible thin-film-shape device, that could be embedded in a facemask. The proposed device could meet the critical requirements for sampling, concentrating and detecting of exhaled breath biomarkers, thereby opening a new opportunity as part of the flexible electronic systems on face masks to facilitate quantitative breath analyses.

An ultrathin, rapidly fabricated, flexible giant magnetoresistive electronic skin

In recent years, there has been a significant increase in the prevalence of electronic wearables, among which flexible magnetoelectronic skin has emerged as a key component. This technology is part of the rapidly progressing field of flexible wearable electronics, which has facilitated a new human perceptual development known as the magnetic sense. However, the magnetoelectronic skin is limited due to its low sensitivity and substantial field limitations as a wearable electronic device for sensing minor magnetic fields. Additionally, achieving efficient and non-destructive delamination in flexible magnetic sensors remains a significant challenge, hindering their development. In this study, we demonstrate a novel magnetoelectronic touchless interactive device that utilizes a flexible giant magnetoresistive sensor array. The flexible magnetic sensor array was developed through an electrochemical delamination process, and the resultant ultra-thin flexible electronic system possessed both ultra-thin and non-destructive characteristics. The flexible magnetic sensor is capable of achieving a bending angle of up to 90 degrees, maintaining its performance integrity even after multiple repetitive bending cycles. Our study also provides demonstrations of non-contact interaction and pressure sensing. This research is anticipated to significantly contribute to the advancement of high-performance flexible magnetic sensors and catalyze the development of more sophisticated magnetic electronic skins.

Resistive switching behavior and thermal stability in the flexible BEFO/ZnO/LSMO heterostructure for flexible/wearable electronics

With the advent of the internet era, wearable electronic devices and flexible electronic technology are rapidly emerging, and new resistive random access memory (RRAM) based on flexible substrates have thus gained extensive attention. Here, the flexible Bi0·95Er0·05FeO3/ZnO/La0·66Sr0·34MnO3 (BEFO/ZnO/LSMO) heterostructure is prepared on Mica substrate using the sol-gel method. The high resistance state (HRS) to low resistance state (LRS) ratio consistently surpasses 102 under the flat and the 15 mm bending radius state. There is no significant change in the resistive switching (RS) behavior after 30 I–V curve cycles and 103 write/erase operations on the BEFO/ZnO/LSMO heterostructure, which reflects excellent stability. In addition, the device still works properly at 175 °C for dynamic conversion between HRS and LRS. The observed RS behavior in the BEFO/ZnO/LSMO heterostructure is attributed to ion migration and alterations in the potential barrier height at the interfaces. These results suggest that the BEFO/ZnO/LSMO heterostructure based on a flexible Mica substrate plays a crucial role in the development of next-generation portable and flexible electronic systems due to its excellent flexibility and thermal stability.

Condition Monitoring System: A Flexible Hybrid Electronics Approach for Sealed Container Applications

A comparative study is presented between two advanced flexible hybrid electronics (FHE) systems designed for monitoring temperature within storage containers across various industries, including food, pharmaceuticals, agriculture, automotive, and defense. The first system, a copper-flex system (CFS), employs an 88.9 µm polyimide substrate with 35 µm thick copper traces, coated with a 12.5 µm polyimide solder mask. The second system, a printed-flex system (PFS), utilizes a 127 µm polyimide substrate with high-temperature resistance and tensile strength. Conductive silver ink was screen-printed on the PFS substrate, and electronic components including a temperature sensor were attached. Functional and reliability tests were performed to check the accuracy and durability of the temperature sensor. Further, environmental and mechanical characterizations including moisture and insulation resistance, corrosion, elongation, bending, and terminal bond strength tests were performed based on ASTM and IPC-TM650 standards. Moisture and insulation resistance test on the PFS test coupons without a coating layer indicated stable resistance of approximately 18 MΩ, while permanent color change indicated oxidation of copper on uncoated CFS test coupons. After 72 hours of corrosion test, both the CFS and PFS “meander line” test coupons covered with polyimide showed negligible change in weight and resistance, approximately 0.35%. A Young’s modulus of 7.17 GPa and 2.6 GPa was calculated from the elongation test for the CFS and PFS, respectively. Bending tests on PFS revealed negligible average resistance change (0.1%) during 180° bending cycles, while no impact was recorded on the CFS. During the terminal bond strength test, soldered wires detached from the CFS test coupons at an average force of 43 N, while it was 3.8 N on the PFS test coupons. Both systems with polyimide coating layer demonstrate robustness and reliability for diverse applications in various industries.

A mechanics and electromagnetic scaling law for highly stretchable radio frequency electronics

Many classes of flexible and stretchable bio-integrated electronic systems rely on mechanically sensitive electromagnetic components, such as various forms of antennas for wireless communication and for harvesting energy through coupling with external power sources. This efficient wireless functionality can be important for body area network technologies and can enable operation without the weight and bulky size of batteries for power supply. Recently, antenna designs have received increased attention because their mechanical and electromagnetic properties significantly influence the wireless performance of bio-integrated electronics, particularly under excessive mechanical loads. These mechanical factors are critical for skin-integrated electronics during human motion, as complex skin deformations can damage the conductive traces of antennas, such as those used for near-field communication (NFC), leading to yield or fracture and affecting their electromagnetic stability. Serpentine interconnects have been proposed as a geometric alternative to in-plane circular or rectangular spiral antenna designs to improve the elastic stretchability of the metallic traces in NFC antennas and prevent mechanical fractures. Despite the use of serpentine interconnects within the physiologically relevant strain range for skin (<20 %), the electromagnetic stability of the antennas decreases. This instability, reflected by shifts in resonance frequency and scattering parameters due to inductance changes, reduces the antennas' wireless power transfer efficiency and readout range. Therefore, maintaining the electromagnetic stability of antennas, specifically NFC antennas, under various mechanical deformations has become a critical challenge in practical wireless skin-integrated applications, such as sensing and physiological monitoring. Here, we establish a new mechanics and electromagnetic scaling law that quantifies the inductance changes under strain in a rectangular-loop serpentine structure typically used for NFC wireless communication in stretchable electronics. We present a systematic analysis of the antenna's geometric parameters, material properties of the antenna and substrate, and the applied strain on the inductance change. Our findings demonstrate that the relative change of inductance is solely influenced by the serpentine structure's width-radius ratio, arc angle, aspect ratio of the NFC antennas, and the applied strain. Additionally, under physiological strain conditions for the skin, the relative change of inductance can be minimized to preserve the NFC antenna's performance and prevent mechanical fracture and electromagnetic stability loss.

Photoresponsive Janus microfibers array film with tunable electrical anisotropy

A new kind of photoresponsive film is produced by integrating photoconductive material into the type-II anisotropic conductive film. This film consists of orderly arranged Janus microfibers, with each Janus microfiber is comprised of a conductive region and an insulating region. Copper phthalocyanine, as the photoconductive material, is introduced into the conductive regions of these Janus microfibers, and thus the electrical conduction of the conductive regions can be enhanced by applying appropriate external light irradiation, while the insulating regions are basically unaffected. Based on this property, the electrical conduction along with the length direction of the Janus microfibers in the film is adjustable by light, the perpendicular direction along the film surface remains constantly insulating, and thus the electrical anisotropy of the resulting Janus microfibers array film can be tuned under light irradiation. The products have potential applications in flexible electronic devices and control systems.

Non-Volatile Memory Based on ZnO Thin-Film Transistor with Self-Assembled Au Nanocrystals.

Non-volatile memory based on thin-film transistor is crucial for system-on-panel and flexible electronic systems. Achieving high-performance and reliable thin-film transistor (TFT) memory still remains challenging. Here, for the first time, we present a ZnO TFT memory utilizing self-assembled Au nanocrystals with a low thermal budget, exhibiting excellent memory performance, including a program/erase window of 9.8 V, 29% charge loss extrapolated to 10 years, and remarkable endurance characteristics. Moreover, the memory exhibits favorable on-state characteristics with mobility, subthreshold swing, and current on-off ratio of 17.6 cm2V-1s-1, 0.71 V/dec, and 107, respectively. Our study shows that the fabricated TFT memory has great potential for practical applications.

Wireless Flexible System for Highly Sensitive Ammonia Detection Based on Polyaniline/Carbon Nanotubes.

Ammonia (NH3) is a harmful atmospheric pollutant and an important indicator of environment, health, and food safety conditions. Wearable devices with flexible gas sensors offer convenient real-time NH3 monitoring capabilities. A flexible ammonia gas sensing system to support the internet of things (IoT) is proposed. The flexible gas sensor in this system utilizes polyaniline (PANI) with multiwall carbon nanotubes (MWCNTs) decoration as a sensitive material, coated on a silver interdigital electrode on a polyethylene terephthalate (PET) substrate. Gas sensors are combined with other electronic components to form a flexible electronic system. The IoT functionality of the system comes from a microcontroller with Wi-Fi capability. The flexible gas sensor demonstrates commendable sensitivity, selectivity, humidity resistance, and long lifespan. The experimental data procured from the sensor reveal a remarkably low detection threshold of 0.3 ppm, aligning well with the required specifications for monitoring ammonia concentrations in exhaled breath gas, which typically range from 0.425 to 1.8 ppm. Furthermore, the sensor demonstrates a negligible reaction to the presence of interfering gases, such as ethanol, acetone, and methanol, thereby ensuring high selectivity for ammonia detection. In addition to these attributes, the sensor maintains consistent stability across a range of environmental conditions, including varying humidity levels, repeated bending cycles, and diverse angles of orientation. A portable, stable, and effective flexible IoT system solution for real-time ammonia sensing is demonstrated by collecting data at the edge end, processing the data in the cloud, and displaying the data at the user end.

Simultaneously enhancing sensitivity and operation range of flexible pressure sensor by constructing a magnetic-guided microstructure in laser-induced graphene composite

Flexible pressure sensors play an essential role in the development of flexible electronic systems, which have been widely used in recent times for human activity monitoring and personal healthcare. However, possessing both high sensitivity and a wide operation range for pressure sensor remains challenging, as these requirements are commonly incompatible with each other. Herein, a magnetic induced graphene composite-based pressure sensor (MIPS) is demonstrated by integrating laser induced graphene (LIG) with a patterned valley-peak microstructure and a graphene film doped with magnetic microspheres. Owing to the synergistic effect of the 3D valley-peak microstructures and intercalation-like microstructures within the LIG composite film, the MIPS demonstrates excellent sensing performance in both sensitivity and operation range. The conductive network formed by graphene flakes improves electromechanical response capability, while the incorporation of magnetic microspheres (MMs) promotes the proliferation of conductive pathways in a small applied pressure range, and the valley-peak structure further enhances compressive strength over a large operation range. Accordingly, the MIPS exhibit excellent sensing capability over a range of 0–830 kPa, with an exceptionally high sensitivity of 4426.12 kPa−1 and excellent mechanical stability and durability (2000 cycles at a pressure of 800 kPa). Additionally, we have developed a novel pressure mapping system utilizing the MIPS array, enabling real-time monitoring of pressure spatial distribution and intensity. Notably, the MIPS array exhibits remarkable potential in diverse applications, including the monitoring of human physiological signals and movement. This pressure sensor with a hierarchically composite microstructure presents a promising candidate for the rapid advancement of next-generation wearable bioelectronics.

Properties and Emerging Applications of Ruthenium Nanoclusters

Abstract Ruthenium nanoclusters have shown great promise as multifunctional nanomaterials in broad scientific and technological sectors. Owing to their distinct characteristics arising from their nanoscale size and tunable electrical configuration, ruthenium nanoclusters are highly useful in photocatalysis, biomedical, electronics, sensors, and energy storage applications. Ruthenium nanoclusters are an effective catalyst with remarkable activity and selectivity. Contact with reactants is facilitated by their large surface area. Size-dependent electronic characteristics enable ruthenium nanoclusters to detect gases and biomolecules with high sensitivity and selectivity. The creation of sophisticated materials for electronic devices, such as transistors, memory chips, and conductive coatings, is facilitated by ruthenium nanoclusters. These materials’ distinct electronic structures enable more effective and flexible electronic systems, and consequently improve device performance. Because of their stability and biocompatibility, ruthenium nanoclusters are used in the biomedical industry as drug delivery systems and imaging agents. Finally, ruthenium nanoclusters have shown photocatalytic efficiency in light-driven chemical processes, and thus may aid in solar energy conversion and environmental cleanup. Their roles in sustainable uses of solar energy may make these materials valuable for solving global problems.

Nucleic acid-based wearable and implantable electrochemical sensors.

The rapid advancements in nucleic acid-based electrochemical sensors for implantable and wearable applications have marked a significant leap forward in the domain of personal healthcare over the last decade. This technology promises to revolutionize personalized healthcare by facilitating the early diagnosis of diseases, monitoring of disease progression, and tailoring of individual treatment plans. This review navigates through the latest developments in this field, focusing on the strategies for nucleic acid sensing that enable real-time and continuous biomarker analysis directly in various biofluids, such as blood, interstitial fluid, sweat, and saliva. The review delves into various nucleic acid sensing strategies, emphasizing the innovative designs of biorecognition elements and signal transduction mechanisms that enable implantable and wearable applications. Special perspective is given to enhance nucleic acid-based sensor selectivity and sensitivity, which are crucial for the accurate detection of low-level biomarkers. The integration of such sensors into implantable and wearable platforms, including microneedle arrays and flexible electronic systems, actualizes their use in on-body devices for health monitoring. We also tackle the technical challenges encountered in the development of these sensors, such as ensuring long-term stability, managing the complexity of biofluid dynamics, and fulfilling the need for real-time, continuous, and reagentless detection. In conclusion, the review highlights the importance of these sensors in the future of medical engineering, offering insights into design considerations and future research directions to overcome existing limitations and fully realize the potential of nucleic acid-based electrochemical sensors for healthcare applications.

Designs and Applications for the Multimodal Flexible Hybrid Epidermal Electronic Systems.

Research on the flexible hybrid epidermal electronic system (FHEES) has attracted considerable attention due to its potential applications in human-machine interaction and healthcare. Through material and structural innovations, FHEES combines the advantages of traditional stiff electronic devices and flexible electronic technology, enabling it to be worn conformally on the skin while retaining complex system functionality. FHEESs use multimodal sensing to enhance the identification accuracy of the wearer's motion modes, intentions, or health status, thus realizing more comprehensive physiological signal acquisition. However, the heterogeneous integration of soft and stiff components makes balancing comfort and performance in designing and implementing multimodal FHEESs challenging. Herein, multimodal FHEESs are first introduced in 2 types based on their different system structure: all-in-one and assembled, reflecting totally different heterogeneous integration strategies. Characteristics and the key design issues (such as interconnect design, interface strategy, substrate selection, etc.) of the 2 multimodal FHEESs are emphasized. Besides, the applications and advantages of the 2 multimodal FHEESs in recent research have been presented, with a focus on the control and medical fields. Finally, the prospects and challenges of the multimodal FHEES are discussed.

Flexible and wearable electronic systems based on 2D hydrogel composites.

Flexible electronics is a rapidly developing field of study, which integrates many other fields, including materials science, biology, chemistry, physics, and electrical engineering. Despite their vast potential, the widespread utilization of flexible electronics is hindered by several constraints, including elevated Young's modulus, inadequate biocompatibility, and diminished responsiveness. Therefore, it is necessary to develop innovative materials aimed at overcoming these hurdles and catalysing their practical implementation. In these materials, hydrogels are particularly promising owing to their three-dimensional crosslinked hydrated polymer networks and exceptional properties, positioning them as leading candidates for the development of future flexible electronics.

Preparation of Tough and Adhesive PVA/P(AM-AMPS)/Glycerol/Laponite/Na2SO4 Organohydrogels for All-Solid-State Supercapacitors and Self-Powered Wearable Strain Sensors.

Hydrogel electrolytes are ideal for flexible wearable electronic devices because of their high ionic conductivity, flexibility, and biocompatibility. However, some problems, such as poor mechanical properties, low conductivity, and lack of adhesivity, are encountered in the process of hydrogel preparation and application, which restrict the further development of hydrogel electrolytes. In this study, PVA was used as the first network, and P(AM-co-AMPS) as the second network to prepare a double-network hydrogel electrolyte. Laponite and Na2SO4 were introduced into the hydrogel during hydrogel formation as the nanofiller and salt with the salting-out effect to enhance its mechanical properties. The hydrogel electrolyte with high toughness (1663 kJ·m-3), adhesivity (77 kPa), and ionic conductivity (1.7 S·m-1) was obtained. In addition, the hydrogel electrolyte also has excellent antifatigue performance. In the 10 consecutive tensile cycles, the tensile strength does not decay. Due to the high adhesivity of the hydrogel electrolyte, a symmetrical all-solid-state supercapacitor was assembled with a tight interface between the hydrogel electrolyte and the AC/CNT composite electrode. The supercapacitor has a high specific capacitance of 186.1 mF·cm-2 at the current density of 1 mA·cm-2. In addition, the capacitor has good flexibility and can withstand bending at various angles. The hydrogel electrolyte also has excellent strain sensing performance, with an ultrafast tensile response time (0.17 s) and high sensitivity factor (GF = 10.01). Finally, the self-powered sensor system composed of a supercapacitor as the power supply device and hydrogel electrolyte as the sensing part was obtained and applied to human motion monitoring, which provides a potential application in the integrated flexible electronic system.

Stable vortex waves generation by a flexible antenna made of highly conductive graphene film

Electromagnetic waves carrying orbital angular momentum (OAM and vortex waves) attract much attention due to their specific characteristics and prospects for use in wireless communication, biomedical engineering, and imaging. Vortex waves are complex spatial entities; therefore, their stable generation is a quite complicated task, especially in the radio frequency and terahertz wave domains, considering that the corresponding antennas must be precisely adjusted. Such adjusting is very difficult to achieve for flexible antennas, which are now being actively introduced into practice. Here, we propose a design of a flexible antenna that is able to stably generate waves carrying OAM even when being subjected to some bending. The antenna is composed of a ring-shaped resonator made of a highly conductive graphene film deposited on a thin polydimethylsiloxane substrate. The antenna is operated on two mutually orthogonal degenerate TMm1 modes excited by two supply strip lines to generate vortex waves with a desired topological charge. We verify this ability numerically and in a microwave experiment on two antenna prototypes deriving the OAM mode purity by changing the bending radius of the antenna bearing surface, giving it either positive or negative curvature. The obtained experimental results confirm that the antenna has good performance and can be used for flexible electronic devices and communication systems.

Hybrid CMOS and Pseudo-CMOS Organic Memory for Flexible Sensors

In this paper, we propose and elucidate a novel static random access memory (SRAM) for flexible electronic systems using low-voltage organic thin-film transistors. The SRAM can be used for local data storage and post-processing of the signals generated by sensors. This is essential for truly flexible systems. The proposed SRAM utilizes hybrid CMOS and pseudo-CMOS design to enhance stability. The memory cells based on CMOS design style utilize p-type access transistors to improve area efficiency and stability. A degradation-mitigation circuit, based on pseudo-CMOS design style, extends retention time. The proposed circuit, which is comprised of few basic logic gates, is easy to implement and occupies minimum layout area. The SRAM circuit can self-detect degradation and automatically perform a process to mitigate device degradation at the necessary time periods.We confirm the operation of key components in the proposed memory via test chip measurements. Additionally, the effectiveness of the degradation-mitigation circuit has been verified.

A flexible PI/graphene heterojunction optoelectronic device modulated by TENG and UV light for neuromorphic vision system

Artificial neural visual electronic devices have attracted great research interest in the fields of low-power and high-efficiency pattern recognition. However, emulating the hyperpolarized behavior of cone and rod cells and further developing image recognition functionalities encounter formidable challenges due to the inherent optoelectronic effects in semiconductors. Here, a flexible optoelectronic synapse device based on polyimide (PI)/Graphene heterojunction is proposed to effectively emulate human visual functionalities. The PI not only serves as a flexible substrate but also exhibits remarkable UV light absorption capability. Furthermore, the electrical conductivity of graphene channel can be bidirectionally regulated through UV light irradiation and triboelectric nanogenerator (TENG) induced negative gas ions adsorption, corresponding to inhibitory and excitatory behaviors, respectively. The negative photoconductance effect, stemming from the recombination between photogenerated electrons in PI and holes in graphene, endows the emulation of hyperpolarized behavior of cone and rod cells. Various synaptic behaviors, such as paired-pulse facilitation, spike-rate dependent plasticity, short-term depression, and long-term depression, can be achieved by modulating light pulses parameters. Additionally, the TENG-induced gas ions adsorbed on the graphene surface act as floating gate, leading to an increase in graphene conductivity. Continuous pulse stimulation through corona discharge enables long-term potentiation behavior in the synaptic device. Ultimately, combining opto-electrically coupled weight updates with artificial neural network algorithms allows for real-time handwritten digit recognition. This work presents a novel pathway for constructing simple flexible artificial visual electronic systems.

AI-enabled epidermal electronic system to automatically monitor a prognostic parameter for hypertension with a smartphone

We present a wearable, flexible, wireless and smartphone-enabled epidermal electronic system (EES) for the continuous monitoring of a prognostic parameter for hypertension. The thin and lightweight EES can be tightly attached to the chest of a patient and synchronously monitor first lead electrocardiograms (ECG) and seismocardiograms (SCG). To demonstrate the concept, we developed the EES using state-of-the-art cleanroom technologies. Two types of sensors were integrated: A pair of metal electrodes to contact the skin and to record ECG and a vibration sensor based on a thin piezoelectric polymer to record SCG from the same location of the chest, simultaneously. The complete EES was powered by the near field communication functionality of the smartphone. We developed a machine-learning algorithm and trained it on public ECG data and recorded SCG signals to extract characteristic features of the recordings. Binary classifiers were used to automatically annotate peaks. After training, the algorithm was transferred to the smartphone to continuously analyze the timing between particular ECG and SCG peaks and to extract the Weissler’s index as a prognostic parameter for hypertension. Tests with data of healthy control persons and clinical experiments with patients diagnosed with cardio-pulmonary hypertension showed a promising prognostic performance. The presented EES technology could be utilized for pre-screening of cardio-pulmonary hypertension, which is a strong burden in our today’s healthcare system.