Self-powered Nanosystems Research Articles

A biocompatible, eco-friendly, and high-performance triboelectric nanogenerator based on sepiolite, bentonite, and kaolin decorated chitosan composite film

Recent advancements in triboelectric nanogenerators (TENGs) have primarily focused on improving power conversion and generation efficiency. However, challenges still exist in developing TENGs that are affordable and biocompatible. Chitosan, an abundant natural biopolymer derived from marine crustacean shells, and natural clays offer exciting possibilities for developing cost-effective and biodegradable TENG applications. In this study, we present the development of biocompatible and eco-friendly TENGs by incorporating clay-based compounds as natural fillers into chitosan. To construct chitosan/clay-based biocomposite TENGs, we have introduced sepiolite, bentonite, and kaolin, as natural additives, into the chitosan biopolymer matrix. Decorating chitosan with natural clays improves the triboelectric properties of the TENGs, which in turn enhances the output voltage and significantly boosts the electric power density. Chitosan-based TENGs with 3 wt% sepiolite, 1 wt% bentonite, and 1 wt% kaolin demonstrate open circuit voltages of 863, 996, and 963 V, respectively. Moreover, when compared to pure chitosan-based TENG, the chitosan-based TENGs with 3 wt% sepiolite, 1 wt% bentonite, and 1 wt% kaolin show a maximum output peak power increase of 19, 54.4, and 32.6%, respectively. At 1.1 MΩ load resistance, the maximum peak electric power densities of 20.4, 26.5, and 22.8 W/m² are reached for chitosan-based TENGs with 3 wt% sepiolite, 1 wt% bentonite, and 1 wt% kaolin, respectively. Furthermore, we analyzed the surface potential, morphology, roughness, and dielectric constant of chitosan/clay composites to understand the relationship between them and electrical performance. The results demonstrate that the output performances of the chitosan/clay-based TENGs are quite high. TENGs made of biocompatible materials may not only pave the way for the production of environmentally friendly, cost-effective, and efficient TENGs for self-powered nanosystems and biomedical devices but may also shed light on new technologies utilizing natural materials.

A self-powered sound-driven humidity sensor for wearable intelligent dehydration monitoring system

Self-powered wearable sensing systems have attracted great attention for their application in continuous health monitoring, which can reveal real-time physiological information on the body. Here, an innovative self-powered sound-driven humidity sensor for wearable intelligent dehydration monitoring system has been proposed. The sensor is primarily comprised of PTFE membrane, ZnO nanoarrays and Ti thin film. The piezoelectric/triboelectric effect of ZnO nanoarrays/PTFE membrane is coupled with the humidity sensing process. Sound wave can drive PTFE membrane to vibrate, and the contact and separation between PTFE and ZnO can generate electrical signals through piezoelectric/triboelectric effect. At the same time, the surface of the nanostructures can absorb the water molecules, which will influence the electrical output of the device. The device can convert sound energy into electrical output without any external electricity power supply, and the outputting voltage decreases with increasing relative humidity, acting as the sensing signal. The sensor has been integrated with data processing unit and wireless transmission module to form a self-powered wearable intelligent dehydration monitoring system, which can actively monitor the humidity of exhaled breath and transmit the information to the mobile phone. The results can open a possible new direction for the development of sound-driven gas sensors and will further expand the scope for self-powered nanosystems.

Humidity Sustainable Hydrophobic Poly(vinylidene fluoride)-Carbon Nanotubes Foam Based Piezoelectric Nanogenerator.

Light weight lead free, polymer, and carbon nanotubes based flexible piezoelectric nanogenerators have prompted widespread concern for harvesting mechanical energy and powering next generation electronics devices. Herein, lightweight polyvinylidene fluoride (PVDF)-carbon nanotube (CNT) foam was prepared to fabricate humid resistant hydrophobic flexible piezoelectric nanogenerator to converts mechanical energy into electricity for the first time. Hydrophobic piezoelectric PVDF-CNT foam with density of 0.15 g/cm3 was prepared by solution route. PVDF-CNT foam exhibited crystalline and a well-defined chain likes structure with 65% fraction of β-phase. Self-poled PVDF-CNT foam shows piezoelectric charge coefficient (d33) of 9.4 pC/N. High d33 of PVDF-CNT foam is caused by dipole alignment induced by local electric field of CNT in the microcellular structure of PVDF. The developed foam exhibits ultrahigh dielectric constant (ε') ∼ 3048 at 150 Hz. Flexible piezoelectric PVDF-CNT foam based nanogenerator was fabricated, which generates high output voltage ∼12 V and current density of 30 nA/cm2 at small compressive pressure of 0.02 kgf. Piezoelectric output performance was measured under different humid condition and an output voltage up to 8 V was achieved even under 60% RH condition. PVDF-CNT foam exhibited hydrophobic behavior and high surface water contact angle of 139°. Such high output voltage even under small pressure, without applying electrical poling and under humid condition was originated though CNT induced self-alignment of electric dipoles in PVDF polymer. These excellent performances of developed foam based device confirmed its potential application in organic based ultrasensitive self-powered nanosensors and nanosystems.

Non-centrosymmetric zinc silicate-graphene based transparent flexible piezoelectric nanogenerator

Abstract Rapid advancement of transparent flexible electronics has great potential for next-generation energy devices for self-powered nanosystems and nanosensors. Here, we present the transparent and flexible piezoelectric lead free zinc silicate (Zn2SiO4) nanorods-graphene based nanogenerators for harvesting mechanical energies for the first time. A simple and cost effective hydrothermal method was used to synthesize the piezoelectric Zn2SiO4 nanorods with non-centrosymmetricity property. Tetragonal crystal system and dimension of nanorods were investigated using X-ray diffraction spectroscopy and high resolution electron microscopies, respectively. Raman spectra exhibited all characteristic signature peaks of the Zn2SiO4 nanorods. Piezoelectric properties of grown Zn2SiO4 nanorods was confirmed and a piezoelectric charge coefficient (d33) of about 117 p.m./V was obtained through piezoelectric force microscopy study. A high performance piezoelectric hybrid composite nanogenerator was successfully fabricated using polydimethylsiloxane (PDMS) polymer, Zn2SiO4 nanorods and CVD grown monolayer graphene sheet. The average piezoelectric output voltage and current density of 5.5 V and 0.50 μA/cm2 were obtained under very small pressure of 0.15 kgf applied through computer controlled dynamic shaker without applying any external electric poling. The average energy conversion efficiency of the flexible piezoelectric Zn2SiO4: PDMS-based device was found to be ≈ 29.10%. The mechanism of high piezoelectric output performance from Zn2SiO4 nanorods device was discussed and co-related with dielectric, piezoelectric and proper adhesion of graphene sheet with polymer composites.

Study and Review of Advancements in Cutting Edge Inventions of Nanotechnology “Wherever Technology Takes Us the Human Still Has a Key Role to Play”

The world is on the brink of a new technological revolution beyond any human experience. A new more powerful industrial revolution capable of bringing wealth, health and education, without pollution, to every person on the planet. This is the promise of nanotechnology. Nanotechnology has gained increased popularity largely due to the design, creation and utilization of materials whose constituent structures exist at Nanoscale. This paper aims to review all the previous work done and also therecent advancements and cutting edge inventions in nanotechnology. Today most of the products made using nanomaterials have general as well as unique applications like cancer treatment, self-powered Nano systems, Integrated chip fabrications, batteries etc. The recent works in the area of carbon nanotubes, Nano-polymers, nanocomposites, Nano-crystals, Nanoparticles, Nano shells, nanotubes, Nano filters, Nanohorn, nanowires, Nano springs etc. are reportedand the Various risks involved in using nanotechnology is discussed and the futuristic works like CNT processors, Peroforene, super capacitors and flow batteries are also discussed.

A self-powered flexible-vision electronic skin based on piezophototronic GaN nanowires for rapid image recognition

A self-powered flexible-vision electronic skin for rapid image recognition has been fabricated from piezophototronic GaN nanowires. The basic structure of each photodetecting pixel consists of horizontally-aligned GaN nanowires crossing a cross-finger electrode, and 6 × 6 photodetecting pixels that form a patterned sensing matrix. The working mechanism is based on the piezophototronic effect, and the device can harvest a tiny amount of mechanical energy and directly output photodetecting signals without any external electrical power. The output piezoelectric voltage is significantly dependent on UV illumination, and the response is up to ~76 for 80 µW cm−2 light. The response and recovery times are very short. A practical application of the device for rapid image recognition has been simply demonstrated, and this shows the potential for realizing an artificial intelligent retina. This work can promote the development of wearable flexible electronics and expand the scope of self-powered nanosystems.

Review on Nanomaterials and Their Utilization in the Recovery of Waste Mechanical Energy by Using Piezoelectric Nanogenerators

Nano scale materials are defined as a set of substances where at least one dimension is less than approximately 100 nanometers. A nanometer is one millionth of a millimeter- approximately 100,000 times smaller than the diameter of a human hair. Nanomaterials are of interest because at this scale unique optical, magnetic, electrical, and other properties emerge. These emergent properties have the potential for great impacts in electronics, medicine, and other fields. Energy harvesting from the environment is one of the core features of a functional, self-sufficient nanosystem. Self-powered nanosystems combine the nanogenerator with functional nanodevices in order to harvest mechanical energy from the environment into electricity to power nanodevices. It can work independently, without any other external power sources. Piezoelectricity is the electric charge that accumulates in certain solid materials (such as crystals, certain ceramics, and biological matter such as bone, DNA and various proteins) in response to applied mechanical stress.Energy harvesting (or power scavenging) refers to capturing energy from environment, surrounding system or any other source and converting it into a usable form of energy to develop self-power system that doesn’t need external power supply e.g. piezoelectric process. In order to harvest the waste mechanical energy during various processes, piezoelectric properties of different materials such as ZnO can be utilised in order to convert the waste mechanical energy into electrical energy which could further be used.

Hybrid nanomanufacturing of mixed-dimensional manganese oxide/graphene aerogel macroporous hierarchy for ultralight efficient supercapacitor electrodes in self-powered ubiquitous nanosystems

The economic production of wearable energy storage devices exhibiting mechanically-compliable form factors and reliable performance enable exciting opportunities in emerging technologies of consumer electronics, human-machine interface, and the Internet of Things. Here we report a hybrid scheme for designing and nanomanufacturing ultralight, high-performance supercapacitor electrodes through the hydrothermal growth of two-dimensional MnO2 on three-dimensional printed graphene aerogel (GA). The derived mixed-dimensional hierarchical macroporous composite electrodes exhibit superior specific capacitance and excellent cycling stability after thousands of cycles. We further explored the integration of a contact mode triboelectric nanogenerator and a mixed-dimensional MnO2/GA based supercapacitor into a self-powered system that is capable of converting mechanical signals into electrical power and further storing such scavenged power. The holistic integration of energy harvesting and storage units promises the implementation of self-powered wearable devices with greater intelligence that can scavenge and store environmental energy through sustainable pathways for ubiquitous electronics in societally-pervasive applications.

A self-powered electronic-skin for detecting CRP level in body fluid based on the piezoelectric-biosensing coupling effect of GaN nanowire

A self-powered biosensing electronic-skin for real-time blood analysis has been presented based on the piezoelectric-biosensing coupling effect of GaN nanowire. The piezoelectric output generated by GaN nanowires can be regarded as both the power source to drive the device and the piezoelectric-biosensing signal for detecting C-reactive protein (CRP). The outputting voltage of the device immersing in the test solution is significantly affected by the CRP concentration, and the response is up to 78.2% against 0.624 mg ml−1. The CRP antigen-antibody specific binding reaction occurs on the surface of GaN nanowire, it not only influence the surface carrier density but also influence piezoelectric output. The actual application of the device for testing the CRP concentration in rabbit blood samples (fever or not) has been confirmed. The existing results can stimulate a study trend on self-powered nanosystems and promote the development of flexible biosensors.

A self-powered temperature-sensitive electronic-skin based on tribotronic effect of PDMS/PANI nanostructures

A new self-powered temperature-sensitive electronic-skin (e-skin) for real-time monitoring body temperature without external electricity power was fabricated from patterned polydimethylsiloxane/polyaniline (PDMS/PANI) nanostructures. The e-skin can be feasibly attached on the human body and driven by the mechanical motion energy through triboelectric effect. The outputting triboelectric impulse of the PDMS/PANI units is significantly dependent on the local surface temperature of the e-skin, serving as both the power source and temperature sensing signal. The outputting current of the e-skin increases with increasing surface temperature of the device. Under applied bending deformation, the response of the e-skin is up to 63.6 for 38.6 °C. The e-skin can detect minimum temperature change of 0.4 °C. The working mechanism can be ascribed to the coupling effect of triboelectric and semiconductor properties (tribotronic effect). A practical application of the e-skin attaching on the human body for detecting the body temperature range of 36.5–42.0 °C has been simply demonstrated. This work provides a viable method for real-time monitoring body temperature, and can promote the development of wearable temperature sensors and self-powered multifunctional nanosystems.

(Invited) scavenging of Mechanical Energy Using Piezoelectric and Triboelectric Materials

The issue of the research for self-powered nanosystems is likely to integrate different nano-devices into a stand-alone. Such nanosystem, surely, requires a sustainable power source to make the entire package as self-powered one. In this regard, scavenging energy from the environmental sources can be a possible choice for powering nano-systems. Among the others, there are many of mechanical form of energy (such as body movement, muscle stretching) or vibration energy (such as acoustic/ultrasonic wave) which can be converted into electric energy. In here, we have demonstrated some approaches for converting mechanical energy into electric energy by piezoelectric, ferroelectric nanomaterials and triboelectric nanostructures. The technology allowed us to harvest energy which is mostly regarded as wasted mechanical movement/vibration or noises. Moreover, new design of devices have been fabricated, and possible materials for such generators have been explored. The presentation will be continuously dedicated to recent developments and improvements of energy harvesting technology towards self-powered nano-systems.

Experimental Demonstration of Spintronic Broadband Microwave Detectors and Their Capability for Powering Nanodevices

The harvesting of ambient radio-frequency (RF) energy is an attractive and clean way to realize the idea of self-powered electronics. Here we present a design for a microwave energy harvester based on a nanoscale spintronic diode (NSD). This diode contains a magnetic tunnel junction with a canted magnetization of the free layer, and can convert RF energy over the frequency range from 100 MHz to 1.2 GHz into DC electric voltage. An attractive property of the developed NSD is the generation of an almost constant DC voltage in a wide range of frequencies of the external RF signals. We further show that the developed NSD provides sufficient DC voltage to power a low-power nanodevice - a black phosphorus photo-sensor. Our results demonstrate that the developed NSD could pave the way for using spintronic detectors as building blocks for self-powered nano-systems, such as implantable biomedical devices, wireless sensors, and portable electronics.

Ultrathin Piezotronic Transistors with 2 nm Channel Lengths.

Because silicon transistors are rapidly approaching their scaling limit due to short-channel effects, alternative technologies are urgently needed for next-generation electronics. Here, we demonstrate ultrathin ZnO piezotronic transistors with a ∼2 nm channel length using inner-crystal self-generated out-of-plane piezopotential as the gate voltage to control the carrier transport. This design removes the need for external gate electrodes that are challenging at nanometer scale. These ultrathin devices exhibit a strong piezotronic effect and excellent pressure-switching characteristics. By directly converting mechanical drives into electrical control signals, ultrathin piezotronic devices could be used as active nanodevices to construct the next generation of electromechanical devices for human-machine interfacing, energy harvesting, and self-powered nanosystems.

(Invited) Piezoelectric Peptide-Based Energy Harvesters

Nanoscale energy harvester holds promise for the development of self-powered nanosystems, while molecular self-assembly of bio-inspired materials has attracted much research effort in recent years. Here we report the controlled growth of vertically aligned FF peptide microrods and their application in nanogenerators. The peptide has recently been demonstrated as a sustainable and smart material for piezoelectric energy conversion. Utilizing both piezoelectric and triboelectric effects is of significant research interest due to their complementary energy conversion mechanisms. We discovered a simple and efficient approach to integrate the piezoelectric nanogenerator with triboelectric nanogenerator. The stacking one layer atop the piezoelectric peptide-based nanogenerator to form the single-electrode triboelectric nanogenerator eliminate the needed extra electrode and complicated connection found in other devices. The energy conversion process is simplified and improved. This work demonstrated the first biomaterial-based hybrid nanogenerator and significantly advanced the study of smart biomaterials. Our work can enable new applications of bio-inspired materials in areas such as energy harvesting and storage, electromechanical sensing and actuation, drug delivery, as well as fundamental studies of FF-based structures.

Engineered and Laser-Processed Chitosan Biopolymers for Sustainable and Biodegradable Triboelectric Power Generation.

Recent advances achieved in triboelectric nanogenerators (TENG) focus on boosting power generation and conversion efficiency. Nevertheless, obstacles concerning economical and biocompatible utilization of TENGs continue to prevail. Being an abundant natural biopolymer from marine crustacean shells, chitosan enables exciting opportunities for low-cost, biodegradable TENG applications in related fields. Here, the development of biodegradable and flexible TENGs based on chitosan is presented for the first time. The physical and chemical properties of the chitosan nanocomposites are systematically studied and engineered for optimized triboelectric power generation, transforming the otherwise wasted natural materials into functional energy devices. The feasibility of laser processing of constituent materials is further explored for the first time for engineering the TENG performance. The laser treatment of biopolymer films offers a potentially promising scheme for surface engineering in polymer-based TENGs. The chitosan-based TENGs present efficient energy conversion performance and tunable biodegradation rate. Such a new class of TENGs derived from natural biomaterials may pave the way toward the economically viable and ecologically friendly production of flexible TENGs for self-powered nanosystems in biomedical and environmental applications.

(Invited) Flexible Piezo-, Tribo-Electric Energy Harvesting Devices for Self-Powered Nanosensor Systems

Flexible devices have been drawn a great attention as next-generation electronic devices. Especially for flexible and wearable system, the challenge to achieve such systems are the development of functional and flexible new materials and unique integration method of conventional devices into flexible ones including high performances. Nevertheless, such nanosystem also requires a power source to make the entire package small, sustainable and even long lasting. In this regards, harvesting energy from the environment is a choice for powering nanosystems. As for the goal, it is desired to explore flexible and wearable devices for scavenging energy around our surroundings, thus it can supply the power to nanosensor system without consuming much battery or to supporting battery life. Here, we will present some approaches for converting mechanical energy into electric energy using piezoelectric or triboelectric effects. This technology may make it possible to harvest energy from certain mechanical movements or human activity. Moreover, self-powered nano-sensor systems have been fabricated by combining the energy harvesting technology which ensures its compatibility and perspective. The presentation will be continuously dedicated to recent developments and improvements of energy harvesting technology towards self-powered nano-systems such as mobile electronics and wearable healthcare.

Fabrication and characterization of piezoelectric nanogenerator based on Al/ZnO/Au structure

PurposeThe purpose of this research work is to harvest energy using the piezoelectric properties of ZnO nanowires (NW). Fabrication and characterization of the piezoelectric nanogenerator (NG), based on Al/ZnO/Au structure without using hosting layer, were done to harvest energy. The proposed method has full potential to harvest the cost-effective energy.Design/methodology/approachZnO NW were fabricated between the thin layers of Al- and Au-coated substrates for the development of piezoelectric NG. To grow ZnO NW, ZnO seed layer was prepared on the Al-coated substrate, and then ZnO NW were grown by aqueous chemical growth method. Finally, Au top electrode was used to conclude the Al/ZnO/Au NG structure. The Al and Au electrodes were used to establish the ohmic and Schottky contacts with ZnO NW, respectively.FindingsSurface morphology of the fabricated device was done by using scanning electron microscopy, and electrical characterization of the sample was performed with digital oscilloscope, picoammeter and voltmeter. The energy harvesting experiment was performed to excite the presented device. The fabricated piezoelectric-sensitive device revealed the maximum open circuit voltage up to 5 V and maximum short circuit current up to 30 nA, with a maximum power of 150 nW. Consequently, it was also shown that the output of the fabricated device was increased by applying the stress. The presented work will help for the openings to capture the mechanical energy from the surroundings to power up the nano/micro-devices. This research work shows that NGs have the competency to build the self-powered nanosystems. It has potential applications in biosensing and personal electronics.Originality/valueThe fabrication of simple and cost-effective piezoelectric NG is done with a structure of Al/ZnO/Au without using hosting layer. The presented method elucidates an efficient and cost-effective approach to harvest the mechanical energy from the native environment.

Optimal geometrical design of inertial vibration DC piezoelectric nanogenerators based on obliquely aligned InN nanowire arrays.

Piezoelectric nanogenerators have been investigated to generate electricity from environmental vibrations due to their energy conversion capabilities. In this study, we demonstrate an optimal geometrical design of inertial vibration direct-current piezoelectric nanogenerators based on obliquely aligned InN nanowire (NW) arrays with an optimized oblique angle of ∼58°, and driven by the inertial force of their own weight, using a mechanical shaker without any AC/DC converters. The nanogenerator device manifests potential applications not only as a unique energy harvesting device capable of scavenging energy from weak mechanical vibrations, but also as a sensitive strain sensor. The maximum output power density of the nanogenerator is estimated to be 2.9 nW cm-2, leading to an improvement of about 3-12 times that of vertically aligned ZnO NW DC nanogenerators. Integration of two nanogenerators also exhibits a linear increase in the output power, offering an enormous potential for the creation of self-powered sustainable nanosystems utilizing incessantly natural ambient energy sources.

A Light Sensitive Nanogenerator for Self‐Powered UV Detection with Two Measuring Ranges

An integrated UV sensor with two measuring ranges for self-powered UV light detection is fabricated, which itself can simultaneously harvest the mechanical energy from the environment and quantitatively detect the intensity of UV light as a self-powered sensor without any storage circuit or external measurement instruments. This work contributes towards the development and application of nanogenerators and self-powered nanosystems.

In-situ synthesis and defect evolution of single-crystal piezoelectric nanoparticles

Piezoelectric nanocrystals have been widely used for self-powered nanosystems, implantable biodevices, wireless sensors and portable/wearable electronics. These nanocrystals function by transforming mechanical deformation into electricity for energy harvesting. Defects are inevitably generated during such mechanical deformations, and these defects are essential for the overall piezoelectric performance or mechanical reliability of piezoelectric nanocrystals. However, defects inside piezoelectric nanocrystals during deformation are rarely investigated, due to the difficulty to obtain direct experimental information. Here, we synthesize and deform piezoelectric nanocrystals sequentially in TEM column to enable in-situ high spatial-resolution study of defects within these nanocrystals. Planar defects form and evolve due to the internal strain caused by piezoelectricity of nanocrystals. The elimination of these defects are also directly observed due to annealing effect of electron beam irradiation. Throughout the whole deformation processes of nanocrystals, planar defects are found to be the dominating defect type. The present technique can also be applied for studying deformation mechanisms of other piezoelectric nanocrystals, as a complementary approach to nanoindentation TEM holder. The obtained insights here in defects evolution and deformation mechanisms of piezoelectric nanocrystals would be beneficial for controlling their piezoelectric performances and mechanical reliabilities.