Pyroelectric Nanogenerator Research Articles

Hybrid nanogenerator for self-powered object recognition

Energy harvesting systems, including piezoelectric (PENG), triboelectric (TENG), and pyroelectric (PYNG) nanogenerator technologies, have emerged as one of the major future energy solutions. Energy harvesting eliminates the need for conventional batteries and encourages eco-friendly alternatives. This study reports hydrothermally synthesized BaTiO3 (BTO) particles with a tetragonal symmetry for hybrid energy harvesting. BTO particles are incorporated with PDMS at various wt% to form a flexible composite film. The 15 wt% BTO-PDMS composite/Al hybrid device (PENG-TENG) produces a peak voltage of 100 V, a current of 980 nA, and a charge of 17 nC, generating a peak power output of 33.64 μW at 100 MΩ. Furthermore, integrating this HNG (external hybridization) yielded an output of 101 V and 980 nA, demonstrating practical applicability. HNG is also employed to interact by touching various objects at different temperatures. The pyroelectric behavior of BTO allows direct thermal sensing of the object. The signals produced are processed using a convolutional neural network (CNN)-based object recognition system, which achieved a remarkable classification accuracy of 99.27% for various objects. External hybridization improves energy efficiency, representing a huge step forward in sustainable technology applications. This research paves the way for developing hybrid energy harvesters and can be employed further for extremely precise battery-free object recognition systems. This unique hybrid nanogenerator, which combines pyroelectric, piezoelectric, and triboelectric components, represents a new method of self-powered object detection. External hybridization improves energy efficiency, representing a huge step forward in sustainable technology applications.

A π-conjugated organic pyroelectric nanogenerator (OPyNG) based on pyrophototronic effect

This report provides a proof of concept for the realization of an organic pyroelectric nanogenerator which encompasses the fabrication and study of charge driven π-conjugated hetero-system by pyrophototronic effect. A rectifying junction is created with polycrystalline graphene-based material, and crystalline polyaniline-rubrene thin-film which belongs to the aromatic class of organic materials where light-induced change in surface layer polarization helps the device to achieve pyroelectric behavior. The fabricated device is self-sustainable and can generate current as well as voltage in self-powered mode. Overall, this work reveals the viable alternatives and new perspectives for harnessing power from organic materials to realize an organic pyroelectric nanogenerator.

Multi‐Effects Coupled Nanogenerators for Simultaneously Harvesting Solar, Thermal, and Mechanical Energies

AbstractAs a result of the widespread use of small‐scale and low‐power electronic devices, the demand for micro‐energy sources has increased, in particular the potential to harvest the wide variety of energy sources present in their surrounding environment. In this paper, a novel coupled nanogenerator that can realize energy harvesting for multiple energy sources is reported. Based on the unique electrical properties of ferroelectric Bi0.5Na0.5TiO3 (BNT) materials, it is possible to combine a photovoltaic cell, pyroelectric nanogenerator, and triboelectric‐piezoelectric nanogenerator in a single element to harvest light, heat, and mechanical energy simultaneously. To evaluate the effectiveness of coupling for different materials, a Yang coupling factor (kC,Q) is defined in terms of transferred charge, where BNT has the largest kC,Q of 1.29 during heating, indicating that BNT has the best coupling enhancement compared to common ferroelectric materials. This new criterion and novel device structure therefore provide a new basis for the future development of coupled nanogenerators which are capable of harvesting multiple sources of energy.

Achieving milliwatt level solar-to-pyroelectric energy harvesting via simultaneous boost to photothermal conversion and thermal diffusivity

Pyroelectric technology is an effective strategy to harvest ambient waste heat into electrical energy to tackle global energy and environmental crises. However, current pyroelectric generators are often limited by low effective power output. Herein, we develop a non-contact, solar-induced pyroelectric nanogenerator (S-PENG) which integrates Au@CNT as solar-thermal layer and polarized PVDF film as pyroelectric layer. The high thermal conductivity of CNT accelerates the heat transfer process, while its strong solar-thermal effect can be coupled with the plasmonic effect of Au nanoparticles to obtain a hybrid ensemble with superior light absorption and conversion. Notably, the solar-thermal temperature of Au@CNT/PVDF rapidly increases from 38 °C to 79.6 °C within 30 s under sunlight irradiation, with a corresponding temperature change rate reaching a maximum of 14.3 °C/s. The drastic temperature fluctuation is crucial to improve the output performance of our S-PENG. More importantly, our S-PENG successfully generates a notable 1.5 mW/m2 output power under a 200 MΩ load (at 20 ℃), thereby overcoming the performance bottleneck of traditional S-PENG designs with micro-watt power output. Our design offers a promising approach to efficiently utilize green solar energy to alleviate our demand on limited energy resources and reduce carbon footprint.

Flexible wearable hybrid nanogenerator to harvest solar energy and human kinetic energy

Solar energy is a clean energy and it is ubiquitous. The movement of people will generate kinetic energy and happened at any time. If solar energy and human kinetic energy could be harvest at the same time, it will be of great significance. In this paper, we used CNTs to fabricate a solar-thermal structure with special concave surface. The solar-thermal conversion ability of this solar-thermal structure is 14.3% higher than other CNTs surface. One side electrode of the pyroelectric nanogenerator was replaced with multi-strip conductive mesh, which can not only conduct electricity, but also cut the magnetic induction line many times to generate electricity. A compact hybrid nanogenerator was fabricated, the thickness is only 410 µm and the density is only 0.065 g/cm2. The hybrid nanogenerator is very light and thin, so it is very suitable for people wear. Experiments show that the output power density of hybrid nanogenerator can reach 2.78 mW/m2. When participants worn the hybrid nanogenerator during walking and running, it can harvest solar energy and human kinetic energy at the same time. The obtained electrical energy can drive a hygrothermograph to work. In a word, a flexible wearable hybrid nanogenerator to harvest solar energy and human kinetic energy is presented in this paper. This hybrid nanogenerator is suitable for people to wear during outdoor sports, and can realize power supply for outdoor electronic devices.

Phase transition enhanced pyroelectric nanogenerators for self-powered temperature sensors

Pyroelectric materials are of interest for waste heat utilization and thermal detection. However, the low output current and inefficiency reduces their effectiveness. Here, we utilize the abrupt decrease in polarization of ferroelectric BaTiO3 materials around Curie temperature to improve the output performance of a pyroelectric nanogenerator. The variation of the polarization leads to a large change in the density of surface free charges, resulting in an increase of pyroelectric current. We have designed a temperature control and recording system to realize direct measurement of the pyroelectric output current. The pyroelectric current, power and energy conversion efficiency of the device near the Curie temperature were measured to be 15.6-fold, 18-fold and 15.8-fold higher than those acquired near room temperature. Moreover, the temperature induced current and charge density enhancement can be applied to detect temperature and temperature change. The responsivity of the self-powered temperature sensor near Tc is 120 nC/cm2∙K, which 4.8 times higher than that near room temperature (25.1 nC/cm2∙K). The results confirmed the ability to exploit a ferroelectric phase transition for pyroelectric performance enhancement.

Boosting solar-to-pyroelectric energy harvesting via a plasmon-enhanced solar-thermal conversion approach

Pyroelectric technology promises the potential transformation of waste heat into useful electrical energy to address the global energy and environmental crises. However, current designs suffer from low power output and the need for additional mechanical devices to drive pyroelectric conversion. Here, we introduce an efficient sunlight-triggered pyroelectric nanogenerator (S-PENG) by combining an Au@polyethylenimine modified graphene oxide (Au@rGO-PEI)-based solar-thermal layer with a PVDF pyroelectric layer. Our strategy integrates rGO’s photothermal properties and Au nanoparticles’ plasmonic effects to boost sunlight absorption for enhanced pyroelectric conversion. When S-PENG is irradiated with sunlight, solar-thermal temperature rapidly reaches ~68 °C in 30 s which is 23 °C higher than neat PVDF. The superior solar-thermal conversion consequently enables Au@rGO-PEI/PVDF to achieve a high power output of 940 μW/m2 that is up to 35-fold better than other pyroelectric devices. By further incorporating S-PENG onto rotating windmill blades, we showcase a blade-type pyroelectric generator for direct solar energy harvesting without needing external light intensity adjustment device. This unique design functions efficiently at various outdoor environments (e.g. temperature, wind, and rain), notably achieving a high power output of 2700 μW/m2 that can be stored in a capacitor (Voc, ~ 5.2 V, 300 s charging). Our work offers valuable insights for the design of next-generation S-PENG and their facile integration with other energy technologies (e.g. windmill) for concurrent electricity harvesting from different green energy sources.

Effects of patterned electrode on near infrared light-triggered cesium tungsten bronze/poly(vinylidene)fluoride nanocomposite-based pyroelectric nanogenerator for energy harvesting

Pyroelectric nanogenerators (PyNG) are crucial to convert waste heat into electrical energy. In this study, we develop PyNG device with screen-printed serpentine electrode (SRE) and we modify with cesium tungsten bronze (Cs0.33WO3). We incorporate Cs0.33WO3 into both the electrode and poly(vinylidene)fluoride (PVDF) layers. We investigate effects of Cs0.33WO3 on pyroelectric response and photothermal conversion and electrode pattern effects on the pyroelectric properties. The electrode pattern remarkably improves pyroelectric response in which SRE pattern with width of 2 mm (Sample 2 (S2)) presents the highest electrical current and power. Moreover, the PVDF/Cs0.33WO3 PyNG device possesses outstanding photothermal conversion and pyroelectric response in comparison to PVDF-based PyNG device. Particularly, temperature of the device with 7 wt% Cs0.33WO3 reaches 121 °C and it shows electrical output responses of 4.36 V and 214 nA. It also generates a power density of 23.28 μW/m2 at a loading resistance of 20 MΩ. The electrical energy PyNG device generate power liquid crystal display (LCD) and four light-emitting diodes (LEDs). Our PyNG device presents better pyroelectric properties than that of PyNG device in open literature. This study represents an alternative to design and develop PyNG devices to harvest solar energy.

Pyroelectric Nanogenerator Based on an SbSI-TiO2 Nanocomposite.

For the first time, a composite of ferroelectric antimony sulfoiodide (SbSI) nanowires and non-ferroelectric titanium dioxide (TiO2) nanoparticles was applied as a pyroelectric nanogenerator. SbSI nanowires were fabricated under ultrasonic treatment. Sonochemical synthesis was performed in the presence of TiO2 nanoparticles. The mean lateral dimension da = 68(2) nm and the length La = 2.52(7) µm of the SbSI nanowires were determined. TiO2 nanoparticles served as binders in the synthesized nanocomposite, which allowed for the preparation of dense films via the simple drop-casting method. The SbSI–TiO2 nanocomposite film was sandwiched between gold and indium tin oxide (ITO) electrodes. The Curie temperature of TC = 294(2) K was evaluated and confirmed to be consistent with the data reported in the literature for ferroelectric SbSI. The SbSI–TiO2 device was subjected to periodic thermal fluctuations. The measured pyroelectric signals were highly correlated with the temperature change waveforms. The magnitude of the pyroelectric current was found to be a linear function of the temperature change rate. The high value of the pyroelectric coefficient p = 264(7) nC/(cm2·K) was determined for the SbSI–TiO2 nanocomposite. When the rate of temperature change was equal dT/dt = 62.5 mK/s, the maximum and average surface power densities of the SbSI–TiO2 nanogenerator reached 8.39(2) and 2.57(2) µW/m2, respectively.

Triboelectric Nanogenerators and Hybridized Systems for Enabling Next-Generation IoT Applications.

In the past few years, triboelectric nanogenerator-based (TENG-based) hybrid generators and systems have experienced a widespread and flourishing development, ranging among almost every aspect of our lives, e.g., from industry to consumer, outdoor to indoor, and wearable to implantable applications. Although TENG technology has been extensively investigated for mechanical energy harvesting, most developed TENGs still have limitations of small output current, unstable power generation, and low energy utilization rate of multisource energies. To harvest the ubiquitous/coexisted energy forms including mechanical, thermal, and solar energy simultaneously, a promising direction is to integrate TENG with other transducing mechanisms, e.g., electromagnetic generator, piezoelectric nanogenerator, pyroelectric nanogenerator, thermoelectric generator, and solar cell, forming the hybrid generator for synergetic single-source and multisource energy harvesting. The resultant TENG-based hybrid generators utilizing integrated transducing mechanisms are able to compensate for the shortcomings of each mechanism and overcome the above limitations, toward achieving a maximum, reliable, and stable output generation. Hence, in this review, we systematically introduce the key technologies of the TENG-based hybrid generators and hybridized systems, in the aspects of operation principles, structure designs, optimization strategies, power management, and system integration. The recent progress of TENG-based hybrid generators and hybridized systems for the outdoor, indoor, wearable, and implantable applications is also provided. Lastly, we discuss our perspectives on the future development trend of hybrid generators and hybridized systems in environmental monitoring, human activity sensation, human-machine interaction, smart home, healthcare, wearables, implants, robotics, Internet of things (IoT), and many other fields.

Nanogenerator as self-powered sensing microsystems for safety monitoring

A fast and accurate real-time safety monitoring system can encourage people to work and live more safely and comfortably. Developing flexible, portable, and sustainable microsystems to monitor the safety status remains a challenge in the electronic devices. These traditional’ sensors always bring about enormous time-consuming energy and complex power supply wire arrangements. Nanogenerator (NG), an emerging energy-harvesting device, provides a pathway to sense different safety-related information (SRI) without external power sources. So far, by different operating mechanisms, NGs, including piezoelectric nanogenerator (PENG), triboelectric nanogenerator (TENGs), and pyroelectric nanogenerator (PyNGs), have a booming development in safety monitoring. This work provides a comprehensive review of the safety monitoring application based on NGs for monitoring SRI about environments, machines, and human, such as hazard sources in the workplace, abnormal machine status, and unhealthy worker. Meanwhile, several methods of processing SRI and typical NGs safety monitoring systems are summarized. Finally, the perspectives and challenges about the future development and application of NGs for safety monitoring were also discussed. It is anticipated that NG sensors will promote a low-cost, precise and intelligent way for safety monitoring, which is expected to bring a new safety concept at technical aspects.

Local hot charge density regulation: Vibration-free pyroelectric nanogenerator for effectively enhancing catalysis and in-situ surface enhanced Raman scattering monitoring

Abstract Highly efficient catalysis and monitoring play an extremely important role in the modern chemical industry. The local thermal charge density, which is proportional to the square of the local near-field enhancement, is essential to improve the catalytic efficiency. However, the vibration-free way to improve the local hot charge density at the surfaces of the catalyst still needs to be investigated. Optical energy is one of the most promising green energy sources in the natural environment. Here, we designed a pyroelectric nanogenerator by absorbing optical energy as surface enhanced Raman scattering (SERS) substrate for in-situ monitoring the complete oxidation reaction from 4-aminothiophenol (4-ATP) to 4-nitrothiophenol (4-NTP) and the oxygen reduction reaction (ORR) intermediates. The pyroelectricity could be easily generated by the simulated sunlight illumination and was investigated in theory and experiment. The electric field induced by the coupling of pyroelectric and plasmonic effect can effectively tune the hot charge density on the surface of SERS substrate, which further increases the SERS signals and efficiently drives the catalytic process. The proposed measuring strategies of catalytic and SERS enhancement can promote energy conservation and environmental protection.

A self-powered, flexible ultra-thin Si/ZnO nanowire photodetector as full-spectrum optical sensor and pyroelectric nanogenerator.

In this work, a new type of self-powered, high-performance ultra-thin p-Si/n-ZnO nanowire (NW) flexible photodetector (PD) and its application as full-spectrum optical sensor and pyroelectric nanogenerator (PENG) are demonstrated. The working mechanism of PDs for PENGs is carefully investigated and systematically analyzed. The self-powered PDs exhibit high responsivity (1200 mA/W), high detectivity (1013 Jones) and fast response (τr = 18 μs, τf = 25 μs) under UV illumination. High and stable short-circuit output currents at each wavelength from ultraviolet (UV) to near-infrared (NIR) demonstrates that the device can realize full-spectrum optical communication. An experiment in which the PENG powers other devices is designed to further demonstrate the proposed working mechanism. This work provides an effective approach to realize self-powered, high-performance PDs for full-spectrum communication. Also, the fabrication of the PENG utilizing a simple and low-cost method shows its potential applications in self-powered flexible electronic devices.

A wearable solar-thermal-pyroelectric harvester: Achieving high power output using modified rGO-PEI and polarized PVDF

Abstract Harvesting solar energy via pyroelectric technology is highly desired because it is a sustainable and clean solution to yield electricity. However, the low power output (below 5mW/m2) and bulky device design of traditional devices hinder their practical applicability. Herein, we demonstrate a highly efficient sunlight-triggered pyroelectric nanogenerator (S-PENG) design that achieves unprecedented performance of 21.3 mW/m2 under one sun irradiation. This is achieved via enhancing both the solar harvesting properties and the pyroelectric efficiencies rationally by employing polyethyleneimine (PEI) chemically modified reduced graphene oxide (rGO-PEI), and a pyroelectric layer based on a polarized polyvinylidene fluoride (PVDF) film respectively. Moreover, we demonstrate its practical application by adapting the S-PENG into a wearable outdoor bracelet. Using a facile hand-waving motion to replace the traditional bulky sunlight-alternating device, our compact bracelet can charge a fitness tracker after only 1 h of outdoor exposure, demonstrating its capability to be seamlessly integrated with outdoor sports activities. We expect our rational design to promote the development of S-PENG and pave the way for the utilization of sunlight as a viable on-the-go electrical source.

The recent advances in self‐powered medical information sensors

AbstractMonitoring various medical information distributed throughout the body is of great importance in early clinic diagnosis and treatment of disease. To discover abnormal medical signals and find their causes in good time, the human body should be monitored continuously and accurately. To meet the requirements, various battery‐less and self‐powered information acquisition techniques are invented. In this review, the recent advances in self‐powered medical information sensors (SMIS) with different functions, structure design, and electric performance are summarized and discussed. The SMIS mainly involves triboelectric nanogenerator (TENG), piezoelectric nanogenerator (PENG), pyroelectric nanogenerator (PyNG)/ thermoelectric generator (TEG) and solar cell. Additionally, this review also analyzed the remaining challenges and prospected the development direction of SMIS in future.image

SbSeI pyroelectric nanogenerator for a low temperature waste heat recovery

The low-grade waste heat, which constitutes majority of the total waste heat produced in industrial sector, is very difficult to be recovered. Pyroelectric materials have recently received a great attention for harvesting waste heat due to their ability to convert temperature fluctuations into an electrical energy. A simple, scalable and cheap fabrication method of pyroelectric nanogenerator (PENG) based on antimony selenoiodide (SbSeI) is presented for the first time. It involves a sonochemical synthesis of SbSeI nanowires and their high pressure (100 MPa) compression at room temperature into a bulk sample. Fabricated device has been subjected to thermal fluctuations, thereby generating an electric signal which has been highly correlated to the thermal input. SbSeI PENG has generated electric output up to 11 nA with power density of 0.59(4) μW/m2 upon exposure to heat-cool condition for a temperature variation from 324 K to 334 K. Presented paper reports also the temperature dependences of electric conductance and pyroelectric coefficient of compressed SbSeI nanowires, which has reached the maximum value of 44(5) nC/(cm2K) at 327 K.

A Self-Powered Wearable Pressure Sensor and Pyroelectric Breathing Sensor Based on GO Interfaced PVDF Nanofibers

This paper reports a self-powered, flexible, piezo- and pyro-electric hybrid nanogenerator (NG) device that can be fixed on different locations of human skin for detecting static and dynamic pressu...

Controlled synthesis and room-temperature pyroelectricity of CuInP2S6 ultrathin flakes

Since the very recent discovery of ferroic ordering under two dimensional limit, novel devices based on 2D ferroelectricity or ferromagnetism has attracted a lot of interests and are promising for next generation electronic and optoelectronic applications. We find that, below the transition temperature Tc ~320 K, ultrathin CuInP2S6 (CIPS) nanoflakes down to bilayer are still pyroelectric. Changing the temperature will lead to charge modification at the surface of CIPS. 2D pyroelectric nanogenerator is fabricated which can efficiently convert the pyroelectric charges into electrical current. This work will facilitate novel applications of pyroelectric and ferroelectric materials, including pyroelectric devices, thermal sensors, ultrathin nanogenerators and various van der Waals (vdW) heterostructure at room temperature.

Standard and figure-of-merit for quantifying the performance of pyroelectric nanogenerators

Pyroelectric nanogenerators have emerged as an effective approach for the energy of the new-era, the era of internet of things, with a great potential for harvesting waste heat energy. Here, we present the figure-of-merit for quantifying the output of a pyroelectric nanogenertor. The charge-voltage cycle during temperature cycling has been experimentally performed on a PVDF film and PZT ceramic material. Output energy of 2.53 μJ per cycle and 2.59 mJ per cycle is presented at temperature cycling of 23 K (from 300 to 323 K) and 8 K (from 300 to 308 K) for the PVDF and PZT, respectively. The practicability of the derived figure-of-merit as a universal standard for pyroelectric nanogenerator is further experimentally confirmed and compared with previous results. We believe that it could be useful for optimizing the performance of pyroelectric nanogenerators from both material and structural aspects as well as estimating the generated electricity based on maximum temperature cycling.

Piezo-phototronic and pyro-phototronic effects to enhance Cu(In, Ga)Se2 thin film solar cells

Cu(In, Ga)Se2 (CIGS)-based materials have gained remarkable attention for thin-film photovoltaic applications due to their high absorption coefficient, tunable bandgap, compositional tolerance, outstanding stabilities, and high efficiency. A small increase in the efficiency of CIGS solar cells has huge economic impact and practical importance. As such, we fabricated a flexible CIGS solar cell on amica substrate and demonstrated the enhanced device performance through the piezo- and pyro-phototronic effects based on a ZnO thin film. The device showed enhanced energy conversion efficiency from 13.48% to 14.23% by decreasing the temperature from 31 to 2 °C at a rate of ∼ 0.6 °C·s−1 via the pyro-phototronic effect, and further enhanced from 14.23% to 14.37% via the piezo-phototronic effect by further applying a static compressive strain. A pyro-electric nanogenerator effect was also found to promote the performance of the CIGS solar cell at the beginning of the cooling process. The manipulated energy band of the CIGS/CdS/ZnO heterojunction under the influence of the inner pyroelectric and piezoelectric potentials is believed to contribute to the sephenomena. Applying the piezo- and pyro-phototronic effects simultaneously offers a new opportunity for enhancing the output performance of commercialthin film solar cells.