Pyro-phototronic Effect Research Articles

Circularly Polarized Light-Dependent Pyro-Phototronic Effect from 2D Chiral-Polar Double Perovskites.

Chiral hybrid perovskites combine the advantages of chiral materials and halide perovskites, offering an ideal platform for the design of circularly polarized light (CPL) detectors. The pyro-phototronic effect, as a special mechanism of the photoexcited pyroelectric signal, can significantly improve the performance of photodetectors, whereas it remains a great challenge to achieve pyroelectricity-based CPL detection. In this work, the chiroptical phenomena and the pyro-phototronic effect are combined in chiral-polar perovskites to achieve unprecedented pyroelectric-based CPL detection. Two novel two-dimensional (2D) lead-free chiral-polar double perovskites, S/R-[(4-aminophenyl)ethylamine]2AgBiI8·0.5H2O, are successfully designed and synthesized by introducing chiral organic ligands into metal halide frameworks. Strikingly, the photoresponse is substantially boosted with the support of the pyro-phototronic effect, showing an increased pyro-phototronic current that is 40 times greater than the photovoltaic current. Furthermore, the pyroelectric-based detector possesses excellent CPL detection capacity to distinguish different polarization states of CPL photons, which achieve an impressive glph of up to 0.27 at zero bias. This study provides a brand new process for CPL detection by utilizing the pyro-phototronic effect in chiral-polar perovskites, which opens a new avenue for chiral materials in optoelectronic applications.

Photovoltaic–Pyroelectric coupled effect enhanced photo-responsivity of a p-n heterojunction Self-Powered ultraviolet photodetector

TiO2-based ultraviolet (UV) photodetectors (PDs) with broadband optical detection range are widely used in commercial and military applications. Nevertheless, the self-powered UV PDs of TiO2 nanoarrays (NRs) have relatively low response rates and slow response times. Here, a high responsivity self-powered p-n heterojunction UV PD based on TiO2 NRs: CQDs/FTO and PEDOS/FTO is fabricated by a simple face-to-face assembly process. The pyroelectric effect of TiO2 NRs is enhanced by sensitizing TiO2 NRs with CQDs, which would reduce the bandgap value of TiO2 NR, broaden the range of photoresponse, and reduce recombination of electron-hole. Furthermore, the pyro-phototronic effect of CQDs, the energy level matching from CQDs to PEDOS and the interaction between –OH in CQDs and ethylene oxide groups in PEDOS enhance the performance of the prepared UV PDs. The TiO2 NRs: CQDs//PEDOS UV PDs achieve a high photo-responsivity and photo-detectivity of 150.95 mA/W and 3.73 × 1011 Jones at 0 bias (365 nm), respectively, which are better than those at wavelengths of 380 nm. We also found that the photocurrent induced via the pyro-phototronic effect increases with the light power intensity. This work points the way for photovoltaic and photo-induced pyro-phototronic effects to improve the performance of TiO2 NRs-based UV PDs.

Self-powered CdS nanorods/planar-Si photodetector and its performance optimization by fully developing pyro-phototronic effect

Self-powered performance is a crucial aspect of photodetectors (PDs) as it allows them to function without the need for external power sources. PDs with excellent broadband self-powered property are dependable, cost-effective, and possess high-efficiency photoelectric conversion, making them suitable for various applications. In this manuscript, a simple and low-cost hydrothermal synthesis method is employed to directly deposit cadmium sulfide (CdS) nanorods onto planar silicon (Si) substrate, resulting in a self-powered PD that incorporates a n-CdS nanorods/p-Si heterostructure. Outstanding photoresponses are observed for the PD in the range of 405∼1064 nm and open circuit voltages (Vocs) are significant, proving its prominent broadband self-powered performance. The maximum responsivity (R) and detectivity (D) are 3.92 mA/W and 7.91 × 108 Jones at zero bias, respectively. Besides, as the CdS nanorods grown on the planar Si surface exhibit superior c-axis orientation, the pyroelectric field caused by temperature variation could significantly enhance carrier transport and separation behavior in the heterojunction. Therefore, the optimal R of 64.8 mA/W and D of 1.31 × 1010 Jones are achieved, with an argument of 3450.5%, as well as a fast response time of 190.8/298.4 μs. Furthermore, the light response wavelength extends to 1550 nm, covering visible light to near-infrared, far beyond the spectral limitations of the heterojunction. This high-performance broadband self-powered PD is expected to show great potentials in various applications.

Coupling of Pyro-Piezo-Phototronic Effects in a GaN Nanowire.

In this paper, we systematically investigate the synergistic regulation of ultraviolet and mechanical loading on the electromechanical behavior of a GaN nanowire. The distributions of polarization charge, potential, carriers, and electric field in the GaN nanowire are analytically represented by using a one-dimensional model that combines pyro-phototronic and piezo-phototronic properties, and then, the electrical transmission characteristics are analyzed. The results suggest that, due to the pyro-phototronic effect and ultraviolet photoexcited non-equilibrium carriers, the electrical behavior of a nano-Schottky junction can be modulate by ultraviolet light. This provides a new method for the function improvement and performance regulation of intelligent optoelectronic nano-Schottky devices.

Pyro-Phototronic Effect in All-Inorganic Two-Dimensional Ruddlesden-Popper Ferroelectric Perovskite Thin-films and Photodetection.

Ferroelectric perovskites, where ferroelectricity is embedded in the structure, are being considered for different device applications. In this study, we introduce Cs2PbI2Cl2, an all-inorganic 2D Ruddlesden-Popper (RP) halide perovskite, as a ferroelectric material suitable for pyro-phototronic applications. Thin-films of the all-inorganic perovskite are successfully cast, and they demonstrate ferroelectric properties. Unlike hybrid materials, the ferroelectricity in Cs2PbI2Cl2 does not rely on the organic moiety possessing an electric dipole moment. Instead, the 2D-layer-forming octahedra are twisted and tilted due to a distortion in the bond lengths, leading to the emergence of spontaneous electric polarization. Based on the properties, we fabricate p-i-n heterojunctions by integrating the perovskite with carrier-transport layers. To determine the band-energies of the materials, scanning tunneling spectroscopy and Kelvin probe force microscopy are employed. The band-edges evidence a type-II band-alignment at both interfaces, enabling the material to exhibit both photovoltaic and pyroelectric behaviors when subjected to pulsed illumination. The devices based on the all-inorganic RP perovskite developed in this study exhibit pyro-phototronic effects and serve as self-powered photodetectors without any need for an external bias.

Ultraviolet/visible distinguishable self-powered photodetector enhanced by pyro-phototronic effect in p–n–p junction

Self-powered photodetectors (PDs) with distinguishable wavelength detection have great application potential in intelligent optoelectronics. However, slow response speed, low responsivity, and signal interference prevent its development and applications. Here, an asymmetric bipolar p-NiO/n-ZnO/p-Si heterojunction is designed as a wavelength-distinguishable PD by using two tandem p–n junctions to reduce the wavelength interference and effectively separate photo-generated carriers. Bidirectional transient photocurrents are achieved in the external circuit for ultraviolet and visible detection by smartly using the pyro-phototronic effect induced by the variations of spontaneous polarization and interface-induced polarization within the p–n–p junction. The transient peak-to-peak current are thus significantly improved by 2310% for 325 nm lasing and by 5950% for 442 nm lasing. This approach can be used to realize wavelength-distinguishable detection through flexibly selecting materials and using the pyro-phototronic effect. The designed PD might have potential applications in the fields of environmental detection, smart imaging, and intelligent optoelectronics.

Pyro-Phototronic Aided Self-Powered Photodetector With Hybrid Heterojunction of PQT-12 and CdSe CQDs

This letter examines the pyro-phototronic effect in a photodetector based on PQT-12 and CdSe colloidal quantum dots (CQDs), operating under self-bias. The device employs a hybrid heterojunction between PQT-12 and CdSe CQDs, along with a Pd-electrode. The use of pyroelectric materials, such as CdSe and PQT-12, enhances the device’s efficiency by exploiting the pyro-phototronic effect observed during light transients. The investigation was conducted using both UV and white light sources, and the device demonstrated rapid response to UV light, with a rise and fall time of 14.18 and 28.32ms, respectively. At around 847 nm, the device achieved a maximum current density, and responsivity of 6.67×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A/cm</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , and 4.58 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mA/W</i> , respectively. Additionally, the device’s optical properties were evaluated using the transfer matrix method to determine its suitability for wavelength-specific applications.

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.

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.

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.

Layer dependent pyro-phototronic effect in Al/ nanostructured porous silicon multi-layer (PS-ML) UV sensing Schottky photovoltaic device

The present letter reports layer dependent UV (365 nm) photo-sensing performance in Al: PS-ML: p+-Si Schottky photovoltaic device aided by pyro-phototronic behaviour with incremental value of 156%,221%,128% and pyro response and recovery times of 0.4 s, 0.5 s, 0.7 s and 1 s, 1.3 s, 1.1 s for three PS-ML devices respectively. The open circuit voltage (Voc) and Fill factor (FF) for the devices are found to be -194mV,-200mV,-345mVand29%,32%,29%.

2D Ruddlesden-Popper Polycrystalline PerovskitePyro-Phototronic Photodetectors.

Two-dimensional (2D) Ruddlesden-Popper (RP) layered halide perovskite has attracted wide attentions due to its unique structure and excellent optoelectronic properties. With inserting organic cations, inorganic octahedrons are forced to extend in a certain direction, resulting in an asymmetric 2D perovskite crystal structure and causing spontaneous polarization. The pyroelectric effect resulted from spontaneous polarization exhibits a broad prospect in the application of optoelectronic devices. Herein, 2D RP polycrystalline perovskite (BA)2 (MA)3 Pb4 I13 film with excellent crystal orientation is fabricated by hot-casting deposition, and a class of 2D hybrid perovskite photodetectors (PDs) with pyro-phototronic effect is proposed, achieving temperature and light detection with greatly improved performance by coupling multiple energies. Because of the pyro-phototronic effect, the current is ≈35 times to that of the photovoltaic effect current under 0V bias. The responsivity and detectivity are 12.7mAW-1 and 1.73×1011 Jones, and the on/off ratio can reach 3.97×103 . Furthermore, the influences of bias voltage, light power density, and frequency on the pyro-phototronic effect of 2D RP polycrystalline perovskite PDs are explored. The coupling of spontaneous polarization and light facilitates photo-induced carrier dissociation and tunes the carrier transport process, making 2D RP perovskites a competitive candidate for next-generation photonic devices.

Pyro-phototronic effect

Pyro-phototronic effect

An overview of pyroelectric photodetector: Photoresponse mechanisms and applications

Recently, pyroelectric materials have gained significant interest for energy harvesting, sensing and detection, and so on. For photodetection, pyroelectric photodetectors show great advantages due to high-performance photo-sensing without an external bias voltage. In this review, the pyroelectric coefficients and three types of important figure of merits are introduced. Moreover, the work mechanisms of pyroelectric photodetectors, including light-induced pyroelectric effect, pyroelectric-photoelectric coupled effect, photovoltaic-pyroelectric coupled effect, pyro-phototronic effect, ferro-pyro-phototronic effect, pyro-phototronic and piezo-phototronic coupling effects, and photo-pyroelectric-thermoelectric effect, are systematically summarized. Finally, the survey of the pyroelectric applications for photoresponse is presented, which divided the pyroelectric photoresponse into four major categories consisting ultraviolet detecting, visible detecting, infrared detection, and broadband detection. This review provides a detailed analysis and summarization of the work mechanisms of pyroelectric photodetectors and the photoresponse applications, which will provide significant guidance and inspiration toward designing the improved pyroelectric photodetectors.

Disentangling the Role of the SnO Layer on the Pyro-Phototronic Effect in ZnO-Based Self-Powered Photodetectors.

Self-powered photodetectors (PDs) have been recognized as one of the developing trends of next-generation optoelectronic devices. Herein, it is shown that by introducing a thin layer of SnO film between the Si substrate and the ZnO film, the self-powered photodetector Al/Si/SnO/ZnO/ITO exhibits a stable and uniform violet sensing ability with high photoresponsivity and fast response. The SnO layer introduces a built-in electrostatic field to highly enhance the photocurrent by over 1000%. By analyzing energy diagrams of the p-n junction, the underlying physical mechanism of the self-powered violet PDs is carefully illustrated. A high photo-responsivity (R) of 93mA W-1 accompanied by a detectivity (D*) of 3.1 × 1010 Jones are observed under self-driven conditions, when the device is exposed to 405nm excitation laser wavelength, with a laser power density of 36mW cm-2 and at a chopper frequency of 400Hz. The Si/SnO/ZnO/ITO device shows an enhancement of 3067% in responsivity when compared to the Al/Si/ZnO/ITO. The photodetector holds an ultra-fast response of ≈ 2 µs, which is among the best self-powered photodetectors reported in the literature based on ZnO.

Pyro-Phototronic Effect for Advanced Photodetectors and Novel Light Energy Harvesting.

Pyroelectricity was discovered long ago and utilized to convert thermal energy that is tiny and usually wasted in daily life into useful electrical energy. The combination of pyroelectricity and optoelectronic yields a novel research field named as Pyro-Phototronic, where light-induced temperature variation of the pyroelectric material produces pyroelectric polarization charges at the interfaces of semiconductor optoelectronic devices, capable of modulating the device performances. In recent years, the pyro-phototronic effect has been vastly adopted and presents huge potential applications in functional optoelectronic devices. Here, we first introduce the basic concept and working mechanism of the pyro-phototronic effect and next summarize the recent progress of the pyro-phototronic effect in advanced photodetectors and light energy harvesting based on diverse materials with different dimensions. The coupling between the pyro-phototronic effect and the piezo-phototronic effect has also been reviewed. This review provides a comprehensive and conceptual summary of the pyro-phototronic effect and perspectives for pyro-phototronic-effect-based potential applications.

Improved Dual-Polarity Response via Pyro-phototronic Effect for Filterless Visible Light Communication.

Dual-polarity response photodetectors (PDs) take full advantage of the directivity of the photocurrent to identify optical information. The dual-polarity signal ratio, a key parameter that represents the equilibrium degree of responses to different lights, is proposed for the first time. The synchronous enhancement of dual-polarity photocurrents and the amelioration of the dual-polarity signal ratio are beneficial to the practical applications. Herein, based on the selective light absorption and energy band structure design, a self-powered CdS/PEDOT:PSS/Au heterojunction PD consisting of a p-n junction and a Schottky junction exhibits unique wavelength-dependent dual-polarity response, where the photocurrent is negative and positive in the short and long wavelength regions, respectively. More importantly, the pyro-phototronic effect inside the CdS layer significantly improves the dual-polarity photocurrents with the maximum enhancement factors of 120%, 343%, 1167%, 1577%, and 1896% at 405, 450, 532, 650, and 808 nm, respectively. Furthermore, the dual-polarity signal ratio tends to 1:1 due to different degrees of the enhancement. This work provides a novel design strategy for dual-polarity response PDs with a simple working principle and improved performance, which can supply a substitution for two traditional PDs in the filterless visible light communication (VLC) system.

Pyro-Phototronic Effect Enhanced Pyramid Structured p-Si/n-ZnO Nanowires Heterojunction Photodetector.

The emergence of nanomaterials has brought about the development of miniature photodetectors into a new stage, and ZnO nanomaterials are currently one of the most popular research objects. Here, the performance of a photodetector consisting of micropyramid structured p-Si/n-ZnO NWs heterojunction constructed by an anisotropic chemical etching and hydrothermal method is optimized by using the pyro-phototronic effect, and the photoresponses of the device to 405 and 648 nm lasers are investigated. The results show that, with the introduction of pyro-phototronic effect, the photoresponsivity Rpyro increases to 208 times that of Rphoto when the wavelength is 405 nm and the optical power density is 0.0693 mW/cm2. Moreover, with the increase of the chopper frequency, the photocurrent increases by more than 3 times, and the photoresponsivity is also increased by a factor of 4.5, making it possible to detect ultrafast pulsed light. In addition, in order to increase the current collection efficiency, a thin film Al layer was deposited as the back electrode on the basis of the device, and the photocurrent and photoresponsivity are significantly improved. Finally, the coupling between the pyro-phototronic effect and the piezo-phototronic effect is analyzed by applying compressive strain to the photodetector. When the compressive strain is -1.02%, the photocurrent decreases by 31.4% and the photoresponsivity decreases by 27.9% due to the opposite direction between laser illumination induced pyroelectric polarization charges and compressive strain induced piezoelectric polarization charges. This work not only demonstrates the great potential of pyro-phototronic effect in enhancing the silicon-based heterojunction photodetectors for high-performance photodetection and ultrafast pulsed light detection but also provides assistance for a better understanding of the coupling mechanism between pyro-phototronic and piezo-phototronic effects.

A new approach for broadband photosensing based on Ag2Se/Si heterojunction tuned by Pyro-phototronic effect

With its high carrier mobility and low effective mass characteristics, silver selenide (Ag2Se) emerges as an attractive candidate for use in optoelectronic devices. However, the relatively low responsivity, slow response speed, and need for a large external bias largely limit their practical applications. In this manuscript, a newly photodetector (PD) is fabricated based on the n-Ag2Se/p-Si heterojunction. It is observed that this PD exhibits a broadband response range of 405–1064 nm at zero bias, and the best responsivity (R) and detectivity (D) are obtained to be 3.04 mA/W and 1.67 × 1010 Jones at 1064 nm, respectively, demonstrating its great potential in high-performance self-powered near-infrared (NIR) PD. More importantly, the light-induced pyroelectric effect, which can be employed to modulate the photoelectric processes and improve the photoresponse, is found in the Ag2Se film due to the imperfect orthorhombic structure. When the Pyro-phototronic effect is introduced in the heterojunction, the R and D of the PD are significantly enhanced to 43.32 mA/W and 1.75 × 1011 Jones with an argument of 1425 % , respectively. An ultrafast response time of 64/62 μs is simultaneously achieved under the illumination of a 400 Hz-pulsed laser, the performances of which are much better than those of previously reported Ag2Se-based heterostructure PDs. Besides, the response range is broadened beyond the bandgap of the heterojunction to a near-infrared region of 1550 nm. This study provides a novel pyroelectric material-based self-powered broadband PD and also gives a great promise for designing high-performance infrared ultrafast PD based on the Pyro-phototronic effect.

Large ferro–pyro–phototronic effect in 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 thin films integrated on silicon for photodetection

AbstractCoupling together the ferroelectric, pyroelectric, and photovoltaic characteristics within a single material is a novel way to improve the performance of photodetectors. In this work, we take advantage of the triple multifunctionality shown by 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 (BCZT), as demonstrated in an Al/Si/SiOx/BCZT/ITO thin‐film device. The Si/SiOx acts as an n‐type layer to form a metal–ferroelectric–insulator–semiconductor heterostructure with the BCZT, and with Al and ITO as electrodes. The photo‐response of the device, with excitation from a violet laser (405 nm wavelength), is carefully investigated, and it is shown that the photodetector performance is invariant with the chopper frequency owing to the pyro‐phototronic effect, which corresponds to the coupling together of the pyroelectric and photovoltaic responses. However, the photodetector performance was significantly better than that of the devices operating based only on the pyro‐phototronic effect by a factor of 4, due to the presence of ferroelectricity in the system. Thus, after a poling voltage of −15 V, for a laser power density of 230 mW/cm2 and at a chopper frequency of 400 Hz, optimized responsivity, detectivity, and sensitivity values of 13.1 mA/W, 1.7 × 1010 Jones, and 26.9, respectively, are achieved. Furthermore, ultrafast rise and fall times of 2.4 and 1.5 µs, respectively, are obtained, which are 35,000 and 36,000 times faster rise and fall responses, respectively, than previous reports of devices with the ferro–pyro–phototronic effect. This is understood based on the much faster ferroelectric switching in ferroelectric thin films owing to the predominant 180° domains in a single direction out of plane.