Pyroelectric Research Articles

Broadband Self-Powered CdS ETL-Based MAPbI3 Heterojunction Photodetector Induced by a Photovoltaic-Pyroelectric-Thermoelectric Effect.

CdS, with a noncentrosymmetric structure, is thought as an important electron transport layer (ETL) in perovskite-based devices, but its pyroelectric effect, which can efficiently modulate the optoelectronic processes, is not well explored. In this work, a MAPbI3 heterojunction of CdS/MAPbI3/Spiro-OMeTAD with a c-axis preferred oxygen-doped CdS ETL is developed as a high-performance photodetector (PD). This PD exhibits a stable self-powered property in the spectral range of ∼360-780 nm due to its excellent photovoltaic effect. Moreover, the light-induced pyroelectric potential in the CdS ETL is demonstrated to be an efficient approach for improving the photoresponses, and different effects are observed for different laser irradiations, which can be well understood from their working mechanisms. Upon 450 nm laser irradiation, the photovoltage responsivity (R) is greatly improved from 596.9 to 6383.6 V/W with an increment of 1069.54%. In addition, the response spectrum is also extended outside the bandgap restriction of the MAPbI3 to 1550 nm due to both the pyroelectric and photothermoelectric effects, which is a big breakthrough for the perovskite heterojunction PD. Through turning the external bias voltage and ambient temperature, the coupling mechanisms of the pyroelectric and photovoltaic effects are further analyzed. This work provides an important understanding of designing the CdS ETL-based perovskite heterojunction for broadband high-performance photoelectric devices by introducing the pyroelectric effect.

Ultrathin Pyroelectric Photodetector with Integrated Polarization-Sensing Metasurface.

An abundance of metallic metasurfaces have been realized with miniscule, intricate features capable of tailored scattering, reflection, and absorption; however, high losses through heat limit their use in optoelectronics. Here, codesign of a detector and a polarization-sensing metasurface overcomes this challenge by utilizing the heat generation for integrated pyroelectric detection of the incoming light polarization. Using a nanogap metasurface with asymmetric metallic elements, polarization-sensitive photodetection exhibits high extinction ratios up to 19 for orthogonally polarized light and allows extraction of Stokes parameters with <12% deviation from theoretical values. This polarization-sensitive photodetector is ultrathin, consisting of active layers of only 290 nm, and exhibits fast response times of ∼2 ns. The structure is fully integrated, requiring no external cameras, detectors, or power sources, and points toward the creation of layered, multifunctional devices that utilize exotic metasurface properties for novel and compact sensing and imaging.

Pyro-phototronic effect coupled in self-powered, fast and broadband photodetector based on CIS/CTS heterojunction

The pyro-phototronic effect has been demonstrated as a successful approach to optimize the performance of heterojunction-based photodetector (PD) devices. Beyond the conventional restriction imposed by materials with intrinsic symmetry, pyroelectricity can be induced from the symmetry modulated at the interface of centrosymmetric components. Here, a self-powered PD based on cost-effective and eco-friendly p-type CuInS2 (CIS)/p-type Cu2SnS3 (CTS) nanocrystals (NCs) layers heterostructure is fabricated. By introducing the pyro-phototronic effect derived from the built-in electric field at the CIS/CTS interface, the PD realizes broadband detection in the ultraviolent (UV) (390 nm) to near infrared (NIR) (950 nm) range. The maximum responsivity and detectivity reach 9.053 mA/W and 5.05 × 1010 Jones for 390 nm illumination, 18.8 mA/W and 1.49 × 1011 Jones for 750 nm illumination and 42.5 mA/W and 6.507 × 1011 Jones for 950 nm illumination, at zero bias. These results show a ∼ 6-fold improvement, compared with those only based on the photovoltaic effect-induced photo-response (for 950 nm illumination). Upon 950 nm illumination, PD exhibits a fast photo-response component with rise time and fall time of 49.6 ms and 34.7 ms, respectively. This work offers a simple and promising approach to develop high-performance self-powered and broad-spectrum isotype heterojunction-based PDs (UV–vis-NIR) using the photovoltaic–pyroelectric coupled effect, while are no restricted to non-centrosymmetric materials.

Strong pyroelectric enhancement induced by the evolution of PNRs in paraelectric-phase KTN crystals

KTa1−xNbxO3 crystals exhibit excellent piezoelectric, ferroelectric, and electro-optical properties near the phase transition point, owing to the evolution of polar nanoregions (PNRs). This paper discusses the physical properties of the PNRs in three characteristic temperature ranges and analyzes the dielectric relaxation properties of the crystals. The effects of different heating rates and initial temperatures on the pyroelectric effect are discussed, and the influence of small electric fields on increasing the pyroelectric coefficient is investigated. The polarization characteristics of the crystal were obtained according to the change in the pyroelectric performance, and the influence of different conditions on the dynamic response of the PNRs was analyzed. It is proposed that the evolution of PNRs, induced by external coupling with an internal electric field, significantly affects macroscopic performance.

Mid-infrared pyroelectric detector with metasurface electrode for broadband enhanced absorption

Pyroelectric photodetectors have continuously been an attractive candidate due to their noncryogenic and easy-to-fabricate specifics. Because the detectivity or resolution of the pyroelectric detector is closely related to the absorptivity to incident radiation, we propose a scheme for a metasurface-based pyroelectric detector (MPPD) by constructing its top electrode with an absorptive metasurface composed of nanogrid-patch units. The resonance modes of Fabry–Perot cavity, magnetic dipole and electric dipole are collectively leveraged for the mid-infrared MPPD with optimal broadband absorption plus three absorptive peaks at 3.13 μm, 3.94 μm and 4.8 μm. The mechanisms and field distributions of these resonance peaks are intensively explored and verified for configuration of the metasurface top electrode with optimized geometries. Finally, our scheme achieves an average absorptivity of 94.2% in the mid-infrared range of 3–5 μm, with its thermal response enhanced by 2.6 times that results in a significantly improved pyroelectric current for the detector.

Near–infrared–excited photothermal–pyroelectric synergy promoted paper–based sensing platform for enhanced photoelectrochemical analysis performance

Exploring and regulating photothermal materials–driven pyroelectric effects may aroused remarkable possibilities for the next generation of in–vitro point–of–care diagnosis. In the pursuit of this goals, the powerful impact of near–infrared light (NIR) has been largely neglected. Herein, a concise yet energetic NIR–excited photothermal–pyroelectric sensing platform had been successfully developed for sensitive let–7a detection. To realize it, the energy harvest was firstly achieved from flexibility polyimide–paper–based electrode on photothermal–pyroelectric. Under NIR irradiation, the photothermal–active matrix of ZnO/AgBiS2 with the electronic configuration and allosteric triple–helix effector with pyroelectric SrTiO3 were switched by fluctuation of thermal–field and pyroelectric–field, facilitating the separation of NIR–responsive carriers. During the process, the effector could regulate the activity of the CRISPR–Cas12a system according to the dose of the let–7a, reasonably leading to the precise quantification of targets with the detection limits of 1.68 fM. Besides, the effect of temperature variation on the sensing platform was investigated, revealing the NIR–excited synergy between photothermal effect and pyroelectric field. This work broadens new horizons towards upgrading the overall performance of photoelectrochemical sensing platform by more efficiently.

Features of spontaneous ferroelectric domain nucleation in Ti:LiNbO3 modulators

Integrated optical modulators based on lithium niobate Ti-indiffused waveguides (Ti:LiNbO3) are used extensively for broadband devices that have a high coupling efficiency with optical fibers at a 1.5 μm wavelength window. However, the ferroelectric nature of lithium niobate crystal results in some undesirable effects causing parameters fluctuations. For example, the pyroelectric effect leads to thermal dependent DC-drift and excess optical losses. Therefore, to develop effective compensation methods, it is important to understand the origin of instability. In the interelectrode gap of phase modulators we found needle-like domain defects with switched polarization along a surface layer of the monodomain X-cut lithium niobate substrate. Based on domain nucleation theory and polarization switching behavior, the spontaneous nature of domain nucleation caused by the pyroelectric field was shown and described for the interelectrode gap of the modulator along electrode edges. Considering the corona effect, models of domain nucleation and growth are proposed, and the morphology of needle-like domains is describes based on numerical simulation of the pyroelectric field distribution in the crystal volume. Experimental studies of industrial optical phase modulators characterize the shape and size of domains not only in the interelectrode gap, but also along the boundary of external electrodes proving the pyroelectric type of domain nucleation. Several methods were used for domain visualization-selective chemical etching, piezoresponse force microscopy, and electron scanning microscopy. The present work provides a theoretical and practical basis for future research on stabilization of the parameters for optical phase modulators.

Geometric Thermoelectric Pump: Energy Harvesting beyond Seebeck and Pyroelectric Effects

Thermal-electric conversion is crucial for smart energy control and harvesting, such as thermal sensing and waste heat recovering. So far, researchers are aware of two main ways of direct thermal-electric conversion, Seebeck and pyroelectric effects, each with different working mechanisms, conditions and limitations. Here, we report the concept of Geometric Thermoelectric Pump (GTEP), as the third way of thermal-electric conversion beyond Seebeck and pyroelectric effects. In contrast to Seebeck effect that requires spatial temperature difference, GTEP converts the time-dependent ambient temperature fluctuation into electricity. Moreover, GTEP does not require polar materials but applies to general conducting systems, and thus is also distinct from pyroelectric effect. We demonstrate that GTEP results from the temperature-fluctuation-induced charge redistribution, which has a deep connection to the topological geometric phase in non-Hermitian dynamics, as a consequence of the fundamental nonequilibrium thermodynamic geometry. The findings advance our understanding of geometric phase induced multiple-physics-coupled pump effect and provide new means of thermal-electric energy harvesting.

A Portable Infrared Attenuated Total Reflection Spectrometer for Food Analysis.

The analytical performance of a compact infrared attenuated total reflection spectrometer using a pyroelectric detector array has been evaluated and compared to a conventional laboratory Fourier transform infrared system for applications in food analysis. Analytical characteristics including sensitivity, repeatability, linearity of the calibration functions, signal-to-noise ratio, and spectral resolution have been derived for both approaches. Representative analytes of relevance in food industries (i.e., organic solvents, fatty acids, and mycotoxins) have been used for the assessment of the performance of the device and to discuss the potential of this technology in food and feed analysis.

Enhancement of ferroelectric polarization in magnetoelectric coupled manganese ferrite (MnFe2O4)/P(VDF-TrFE) nanocomposite polymer films at room temperature and solar energy (thermal) harvesting using pyroelectric effect of these films

Enhancement of ferroelectric polarization in magnetoelectric coupled manganese ferrite (MnFe2O4)/P(VDF-TrFE) nanocomposite polymer films at room temperature and solar energy (thermal) harvesting using pyroelectric effect of these films

Pyroelectric effect and piezoelectric properties of composites based on ferroelectric copolymer of poly(vinylidene fluoride-trifluoroethylene) and deuterated triglycine sulfate

In this work, composite films of a copolymer of vinylidene fluoride with trifluoroethylene P(VDF-TrFE) comprising microcrystals of deuterated triglycine sulfate (DTGS) were produced. The pyroelectric properties of the composite samples were studied by the dynamic method. Pyroelectric measurements indicated an extreme dependence of the pyroelectric coefficient on the concentration of DTGS inclusions in the composite. Piezoelectric modules were macroscopically measured in static mode. The measured piezoelectric moduli d 31 and d 33 show ambiguous dependences on the volume fraction of DTGS inclusions.

Photoconductivity, pyroconductivity, and pyroelectricity effects in photodetection of layer-structured CuInP2S6/MoS2 heterojunction

Layer-structured ferroelectric material-modulated heterojunctions are promising for use as photodetectors. However, the mechanism behind their photodetection performance, including photoconductivity, pyroconductivity, and pyroelectricity effects, has not yet been fully studied. Herein, we present a CuInP2S6/MoS2 heterojunction with a layered structure, in which the narrow bandgap of MoS2 extends the detection wavelength range with a specific detectivity (D*) of 108–1010 Jones. The pyroelectric effect, dominated by polarization, introduces significant current peaks and valleys when the light is turned on and off. A competitive mechanism is discovered among the photoconductivity, pyroconductivity, and pyroelectricity effects. At low optical power intensities, the pyroconductivity effect is dominant under 405 nm light, while the pyroelectricity effect dominates under 808 nm light. However, at high optical power intensities, both the photoconductivity and pyroconductivity effects become dominant, regardless of the light wavelength. The responsivity (R), external quantum efficiency (EQE), and D* of the CuInP2S6/MoS2 heterojunction are two orders of magnitude for 405 nm light compared to 808 nm light. These results not only demonstrate the coupling effect among the photoconductivity, pyroconductivity, and pyroelectricity effects in the photodetection of layer-structured CuInP2S6/MoS2 heterojunctions but also highlight the potential applications of these heterojunctions in multifunctional devices, provided that these effects can be clearly distinguished.

Enhanced pyro-/photo catalysis of the pyroelectric PZT/CdS heterostructure for dye decomposition driven by visible light and cold-hot cycles

Semiconductor heterojunction have received wide attention for their enhanced catalytic properties. In this paper, the PZT/CdS pyroelectric heterojunction prepared by hydrothermal method has remarkable pyro-/photo catalytic degradation performance and RhB can be almost completely degraded within 120 min. The pyro-/photo catalytic degradation of RhB by PZT/CdS was 99.25% under 20–55 °C and visible light irradiation, which was 1.5 times and 6 times that of PZT/CdS (64.72%) and PZT (16.35%) photocatalysis, respectively. The increase of decomposition rate is because the introduction of CdS not only expands the light response range of the material, but also improves the redox ability of the material. At the same time, CdS and PZT can also produce pyroelectric effect under temperature fluctuation. Double pyroelectric effect and heterojunction work together to further promote the separation of carriers. This study confirmed that PZT/CdS heterojunctions based on pyroelectric effect can achieve efficient pyro-/photo catalysis by using solar/thermal energy, which provides a reference in the field of catalytic degradation of dye wastewater by multiple energy sources.

Finite element simulation-based prediction of CMOS-compatible pyroelectric material in MEMS IR detectors

Aluminum nitride (AlN) and zinc oxide (ZnO) have immensely drawn the interest of researchers as lead-free and CMOS-compatible materials for pyroelectric applications to replace the existing hazardous materials, namely lead zirconate titanate (PZT), lithium niobate (LiNbO3), and lithium tantalate (LiTaO3) in infrared (IR) detectors applications. This article uses the finite element method (FEM) to conduct a systemic investigation of a micro-electromechanical system (MEMS)-based pyroelectric IR detector using AlN or ZnO as the sensing material. The IR detector is designed over a 1 μm thin silicon dioxide diaphragm with a trapezoidal-shaped cavity of 300 μm depth in the silicon substrate to lower the detector's thermal mass and to increase the rate of change of temperature (dT/dt). The thickness and area of the pyroelectric layer were varied in the ranges of 0.5 to 5 μm and 0.16 to 3.24 mm2, respectively. The studies indicate that the AlN-based IR detector shows better performance than that of ZnO, with dT/dt ∼ 15.65 K/s, voltage responsivity (Rv) ∼ 62.52 V/W, noise equivalent power (NEP) ∼ 4.41 ×10−8 W/√Hz and specific detectivity (D*) ∼ 9.06 × 105 cm√Hz/W for a 0.16 mm2 area and 5 μm thick sensing layer.

Improved pyroelectric effect in PVDF/BaTiO3 composite flexible films mediated by enhanced β – PVDF phase formation

Improved pyroelectric effect in PVDF/BaTiO3 composite flexible films mediated by enhanced β – PVDF phase formation

CMOS AlN and ScAlN Pyroelectric Detectors with Optical Enhancement for Detection of CO2 and CH4 Gases

AbstractGas sensors are useful for monitoring of greenhouse gases. As the move toward complementary metal‐oxide‐semiconductor (CMOS) compatible pyroelectric room temperature detectors is gaining traction due to its scalability to 8‐in./12‐in. wafer area and integrable with CMOS electronics, CMOS compatible aluminum nitride (AlN)‐ and scandium aluminum nitride (ScAlN)‐based pyroelectric detectors are developed for sensing of CO2and CH4gases, which are two of the greenhouse gases that contribute significantly to global warming. Leveraging gas absorption at respective mid‐infrared (IR) wavelengths, CO2 and CH4 gases are detected at various concentrations with fast response time ≈1 s. A compound parabolic collector (CPC) is designed and integrated into the gas sensor to enhance the optical flux received by the detector, which demonstrates ≈10× signal improvement in its presence. Further factors such as the effect of sensing area reduction and response to random gas concentrations are also tested on AlN‐ and ScAlN‐based pyroelectric detectors respectively to observe the gas sensing behaviors of both detectors. The results obtained provide further understanding of the behavior of CMOS AlN‐ and ScAlN‐based pyroelectric detectors as IR gas sensors, which can potentially inspire new design and design selection for various gas sensing applications.

Pyro-Photoelectric Effect Enhanced Dual-Mode Self-Powered ITO/ZnO:Ga Microwire/AlGaN Thin-Film Heterojuncted Ultraviolet Imaging Photodetector

Ultraviolet (UV) photodetectors have received a significant amount of attention in a variety of areas; especially, self-powered photodetectors are anticipated to address the energy-saving demand in the astronautics under the photovoltaic effect. In this work, a ZnO:Ga/Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.1</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.9</sub> N heterojunction is introduced for performing UV photodetector, which is enhanced by the pyro-photoelectric effect coupling of pyroelectric and photovoltaic effects. The heterojunction UV photodetector can operate in a self-powered mode with responsivity of 0.063 mA W <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> under the illumination of 135 μW cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> . More importantly, after pyro-photoelectric enhancement, the photocurrent is effectively increased from 13 pA to 45 pA. Additionally, under the illumination of 493 μW cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> , the photo-to-dark-current ratio ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PDCR</i> ) of 80 and 1.7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> are obtained at reverse bias of -10 V and forward bias of +10 V, respectively, indicating that the heterojunction UV photodetector can be regarded as a dual-mode photodetector since it can operate in both forward-biased photoconductive mode and reverse-biased depletion mode. Moreover, the UV photodetector exhibits a fast temporal pulsed laser response with a rising time of 0.79 ms and decay time of 9.4 ms. In all, this work presents a novel strategy for the advancement of UV detection.

A self-powered ultraviolet photodetector based on TiO2 nanoarrays and poly(3,4-ethylenedioxyselenophene) with the enhanced performance by pyro-phototronic effect

Pyro-phototronic effect plays an important role in improving the photodetection performance of ultraviolet (UV) photodetectors (PDs). Here, a novel pyro-phototronic effect between TiO2 nanoarrays (TiO2 NRs) and the conducting polymer poly(3,4-ethylenedioxy selenophene) (PEDOS) is applied to fabricate a self-powered UV PD with the enhanced photodetection ability. The self-powered p-n heterojunction UV PD is fabricated by a face-to-face hybrid of acid (HCl and H2SO4)-treated TiO2 NRs with PEDOS. Interestingly, a pyro-phototronic effect is found between TiO2 NRs/FTO and PEDOS/FTO, and the acid treatment of TiO2 NRs can dramatically enhance the pyro-phototronic effect. H2SO4 treatment can improve the p-n heterojunction, while HCl treatment can increase carrier concentration due to the introduction of surface oxygen vacancies on the surface of TiO2 NRs. Under UV light illumination and 0 bias voltage, the rise time (Trise) and fall time (Tfall) of UV PD from the face-to-face hybrid of PEDOS/FTO with TiO2(HCl)/FTO are 0.080 s and 0.079 s, while the responsivity (R) and detectivity (D*) are 58.706 mA/W and 3.627 × 1011 Jones, respectively. The face-to-face fabrication of UV PDs and the matching of the energy levels between PEDOS and TiO2 NRs cause the pyro-phototronic effect due to temperature change and pyroelectric effect of TiO2 NRs under the UV light illumination. This work gives a new idea to generate pyro-phototronic effect between TiO2 NRs and conducting polymers for application in UV PDs field.

Highly Sensitive Pyroelectric Detector Using Atomically Thin Nanoscale Silicon Ditelluride

Two-dimensional (2D) materials are increasingly being used as detectors and are gaining popularity due to the advantage of tunability of their electrical and thermal properties. Certain non-centrosymmetric materials exhibit a property known as pyroelectricity, which can be utilized to detect infrared (IR) radiation. On the other hand, the pyroelectric effect can be induced in centrosymmetric materials by making them react to external stimuli that break up their symmetry. Here, we report the pyroelectric behavior of a centrosymmetric 2D SiTe2 by inducing interface polarization in a Schottky junction. For this bulk, SiTe2 was synthesized via induction melting and its 2D counterpart via liquid-phase exfoliation. A pyroelectric photodetector in Au/p-SiTe2/ITO configuration was fabricated. The electrical studies confirm the formation of a Schottky junction. The 2D SiTe2-based pyroelectric detector exhibited a high pyroelectric coefficient of 3.73 mC/m2 K and a good responsivity of 3.9 × 105 Jones. The obtained pyroelectric coefficient using 2D SiTe2 was remarkably superior to that of conventional bulk materials. This enhanced property arises from the combined effect of the two-dimensional nature of the material and the induced interface polarization in the device. We employed density functional theory to support our experimental observations. The performance results suggest that 2D SiTe2 could be a benchmark candidate for ultrafast pyroelectric detectors.

Nanoheterojunction Engineering Enables NIR‐II‐Triggered Photonic Hyperthermia and Pyroelectric Catalysis for Tumor‐Synergistic Therapy

AbstractPhotodynamic therapy (PDT) as a non‐invasive strategy shows high promise in cancer treatment. However, owing to the hypoxic tumor microenvironment and light irradiation‐mediated rapid electron–hole pair recombination, the therapeutic efficacy of PDT is dramatically discounted by limited reactive oxygen species (ROS) generation. Herein, a multifunctional theranostic nanoheterojunction is rationally developed, in which 2D niobium carbide (Nb2C) MXene is in situ grown with barium titanate (BTO) to generate a robust photo‐pyroelectric catalyst, termed as BTO@Nb2C nanosheets, for enhanced ROS production, originating from the effective electron–hole pair separation induced by the pyroelectric effect. Under the second near‐infrared (NIR‐II) laser irradiation, Nb2C MXene core‐mediated photonic hyperthermia regulates temperature variation around BTO shells facilitating the electron–hole spatial separation, which reacts with the surrounding O2 and H2O molecules to yield toxic ROS, achieving a synergetic effect by means of combinaterial photothermal therapy with pyrocatalytic therapy. Correspondingly, the engineered BTO@Nb2C composite nanosheets feature benign biocompatibility and high antitumor efficiency with the tumor‐inhibition rate of 94.9% in vivo, which can be applied as an imaging‐guided real‐time non‐invasive synergetic dual‐mode therapeutic nanomedicine for efficient tumor nanotherapy.