RESUMEN
2D layered metal halide perovskites (MHPs) are a potential material for fabricating self-powered photodetectors (PDs). Nevertheless, 2D MHPs produced via solution techniques frequently exhibit multiple quantum wells, leading to notable degradation in the device performance. Besides, the wide band gap in 2D perovskites limits their potential for broad-band photodetection. Integrating narrow-band gap materials with perovskite matrices is a viable strategy for broad-band PDs. In this study, the use of methylamine acetate (MAAc) as an additive in 2D perovskite precursors can effectively control the width of the quantum wells (QWs). The amount of MAAc greatly affects the phase purity. Subsequently, PbSe QDs were embedded into the 2D perovskite matrix with a broadened absorption spectrum and no negative effects on ferroelectric properties. PM6:Y6 was combined with the hybrid ferroelectric perovskite films to create a self-powered and broad-band PD with enhanced performance due to a ferro-pyro-phototronic effect, reaching a peak responsivity of 2.4 A W-1 at 940 nm.
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Van der Waals junctions hold significant potentials for various applications in multifunctional and low-power electronics and optoelectronics. The multistep device fabrication process usually introduces lattice mismatch and defects at the junction interfaces, which deteriorate device performance. Here the layer engineering synthesis of van der Waals homojunctions consisting of 2H-MoTe2 with asymmetric thickness to eliminate heterogenous interfaces and thus obtain clean interfaces is reported. Experimental results confirm that the homostructure nature gives rise to the formation of pristine van der Waals junctions, avoiding chemical disorders and defects. The ability to tune the energy bands of 2H-MoTe2 continuously through layer engineering enables the creation of adjustable built-in electric field at the homojunction boundaries, which leads to the achievement of self-powered photodetection based on the obtained 2H-MoTe2 films. Furthermore, the successful integration of 2H-MoTe2 homojunctions into an image sensor with 10 × 10 pixels, brings about zero-power consumption and near-infrared imaging functions. The pristine van der Waals homojunctions and effective integration strategies shed new insights into the development of large-scale application for two-dimensional materials in advanced electronics and optoelectronics.
RESUMEN
The interfacial pyro-phototronic effect (IPPE) presents a novel approach for improving the performance of self-powered photodetectors (PDs) based on metal halide perovskites (MHPs). The interfacial contact conditions within the Schottky junctions are crucial in facilitating the IPPE phenomenon. However, the fabrication of an ideal Schottky junction utilizing MHPs is a challenging endeavor. In this study, we present a surface passivation method aimed at enhancing the performance of self-powered photodetectors based on inverted planar perovskite structures in micro- and nanoscale metal-halide perovskite SCs. Our findings demonstrate that the incorporation of a lead halide salt with a benzene ring moiety for surface passivation leads to a substantial improvement in photoresponses by means of the IPPE. Conversely, the inclusion of an alkane chain in the salt impedes the IPPE. The underlying mechanism can be elucidated through an examination of the band structure, particularly the work function (WF) modulated by surface passivation. Consequently, this alteration affects the band bending and the built-in field (VBi) at the interface. This strategy presents a feasible and effective method for producing interfacial pyroelectricity in MHPs, thus facilitating its potential application in practical contexts such as energy conversion and infrared sensors.
RESUMEN
Developing inventive approaches to control crystallization and suppress trap defects in perovskite films is crucial for achieving efficient perovskite photovoltaics. Here, a synchronous regulation strategy is developed that involves the infusion of a zwitterionic ionic liquid additive, pyrrolidinium thiocyanate (PySCN), into the perovskite precursor to optimize the subsequent crystallization and defects. PySCN modification not only orchestrates the crystallization process but also deftly addresses trap defects in perovskite films. Within this, SCN- compensates for positively charged defects, while Py+ plays the role of passivating negatively charged defects. Based on the vacuum flash evaporation without anti-solvent, the air-processed perovskite solar cells (PSCs) with PySCN modification can achieve an extraordinary champion efficiency of 22.46% (0.1 cm2) and 21.15% (1.0 cm2) with exceptional stability surpassing 1200 h. Further, the self-powered photodetector goes above and beyond, showcasing an ultra-low dark current of 2.13 × 10-10 A·cm-2, a specific detection rate of 6.12 × 1013 Jones, and an expansive linear dynamic range reaching an astonishing 122.49 dB. PySCN modification not only signifies high efficiency but also ushers in a new era for crystallization regulation, promising a transformative impact on the optoelectronic performance of perovskite-based devices.
RESUMEN
In this work, we report the design and fabrication of self-powered binary response PDs based on II-type heterostructures consisting of SnSx nanoflakes (NFs) and rutile TiO2 nanorod arrays (NRs). The TiO2 NRs effectively block light with wavelengths below 400 nm from reaching SnSx. Under 385 nm light, the photoelectrons in TiO2 recombine with holes in SnSx at the interface due to the energy band bending, resulting in a positive photocurrent. Under 410 nm light, the photoelectrons in SnSx and the photogenerated holes in TiO2 accumulate at the interface, overcoming the interfacial potential barriers induced by the higher Fermi levels of SnSx and inducing a negative photocurrent. Based on the bipolar response, the dual-band imaging capability without external filters and the light-encrypted OR, AND, and NOT logic gates using a single device are demonstrated. This work provides a blueprint for the development of multifunctional self-powered PDs that can simplify system architecture, reduce the energy consumption, and improve accuracy for applications, such as visual systems, light-controlled logic circuits, and encrypted optical communications.
RESUMEN
Cu2ZnSn(S,Se)4 (CZTSSe) has attracted great interest in thin-film solar cells due to its excellent photoelectric performance in past decades, and recently is gradually expanding to the field of photodetectors. Here, the CZTSSe self-powered photodetector is prepared by using traditional photovoltaic device structure. Under zero bias, it exhibits the excellent performance with a maximum responsivity of 0.77 A W-1, a high detectivity of 8.78 × 1012 Jones, and a wide linear dynamic range of 103 dB. Very fast response speed with the rise/decay times of 0.576/1.792 µs, and ultra-high switching ratio of 3.54 × 105 are obtained. Comprehensive electrical and microstructure characterizations confirm that element diffusion among ITO, CdS, and CZTSSe layers not only optimizes band alignment of CdS/CZTSSe, but also suppresses the formation of interface defects. Such a suppression of interface defects and spike-like band alignment significantly inhibit carrier nonradiative recombination at interface and promote carrier transport capability. The low trap density in CZTSSe and low back contact barrier of CZTSSe/Mo could be responsible for the very fast response time of photodetector. This work definitely provides guidance for designing a high performance self-powered photodetector with high photoresponse, high switching ratio, fast response speed, and broad linear dynamic range.
RESUMEN
The construction of nanostructured Z-scheme heterostructure is a powerful strategy for realizing high-performance photoelectrochemical (PEC) devices such as self-powered photodetectors and water splitting. Considering the band structure and internal electric field direction, BiVO4 is a promising candidate to construct SnS2 -based heterostructure. Herein, the direct Z-scheme heterostructure of vertically oriented SnS2 nanosheet on BiVO4 nanoflower is rationally fabricated for efficient self-powered PEC photodetectors. The Z-scheme heterostructure is identified by ultraviolet photoelectron spectroscopy, photoluminescence spectroscopy, PEC measurement, and water splitting. The SnS2 /BiVO4 heterostructure shows a superior photodetection performance such as excellent photoresponsivity (10.43 mA W-1 ), fast response time (6 ms), and long-term stability. Additionally, by virtue of efficient Z-scheme charge transfer and unique light-trapping nanostructure, the SnS2 /BiVO4 heterostructure also displays a remarkable photocatalytic hydrogen production rate of 54.3 µmol cm-2 h-1 in Na2 SO3 electrolyte. Furthermore, the synergistic effect between photo-activation and bias voltage further improves the PEC hydrogen production rate of 360 µmol cm-2 h-1 at 0.8 V, which is an order of magnitude above the BiVO4 . The results provide useful inspiration for designing direct Z-scheme heterostructures with special nanostructured morphology to signally promote the performance of PEC devices.
RESUMEN
WSe2 has a high mobility of electrons and holes, which is an ideal choice as active channels of electronics in extensive fields. However, carrier-type tunability of WSe2 still has enormous challenges, which are essential to overcome for practical applications. In this work, the direct growth of n-doped few-layer WSe2 is realized via in situ defect engineering. The n-doping of WSe2 is attributed to Se vacancies induced by the H2 flow purged in the cooling process. The electrical measurements based on field effect transistors demonstrate that the carrier type of WSe2 synthesized is successfully transferred from the conventional p-type to the rarely reported n-type. The electron carrier concentration is efficiently modulated by the concentration of H2 during the cooling process. Furthermore, homomaterial inverters and self-powered photodetectors are fabricated based on the doping-type-tunable WSe2. This work reveals a significant way to realize the controllable carrier type of two-dimensional (2D) materials, exhibiting great potential in future 2D electronics engineering.
RESUMEN
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.
RESUMEN
Self-powered photodetectors (PDs) have the advantages of no external power requirement, wireless operation, and long life. Spontaneous ferroelectric polarizations can significantly increase built-in electric field intensity, showing great potential in self-powered photodetection. Moreover, ferroelectrics possess pyroelectric and piezoelectric properties, beneficial for enhancing self-powered PDs. 2D metal halide perovskites (MHPs), which have ferroelectric properties, are suitable for fabricating high-performance self-powered PDs. However, the research on 2D metal halide perovskites ferroelectrics focuses on growing bulk crystals. Herein, 2D ferroelectric perovskite films with mixed spacer cations for self-powered PDs are demonstrated by mixing Ruddlesden-Popper (RP)-type and Dion-Jacobson (DJ)-type perovskite. The (BDA0.7 (BA2 )0.3 )(EA)2 Pb3 Br10 film possesses, overall, the best film qualities with the best crystalline quality, lowest trap density, good phase purity, and obvious ferroelectricity. Based on the ferro-pyro-phototronic effect, the PD at 360 nm exhibits excellent photoelectric properties, with an ultrahigh peak responsivity greater than 93 A W-1 and a detectivity of 2.5 × 1015 Jones, together with excellent reproducibility and stability. The maximum responsivities can be modulated by piezo-phototronic effect with an effective enhancement ratio of 480%. This work will open up a new route of designing MHP ferroelectric films for high-performance PDs and offers the opportunity to utilize it for various optoelectronics applications.
RESUMEN
Interface engineering of the hole transport layer in CH3NH3PbI3 photodetectors has resulted in significantly increased carrier accumulation and dark current as well as energy band mismatch, thus achieving the goal of high-power conversion efficiency. However, the reported heterojunction perovskite photodetectors exhibit high dark currents and low responsivities. Herein, heterojunction self-powered photodetectors, composed of p-type CH3NH3PbI3 and n-type Mg0.2Zn0.8O, are prepared through the spin coating and magnetron sputtering. The obtained heterojunctions exhibit a high responsivity of 0.58 A/W, and the EQE of the CH3NH3PbI3/Au/Mg0.2Zn0.8O heterojunction self-powered photodetectors is 10.23 times that of the CH3NH3PbI3/Au photodetectors and 84.51 times that of the Mg0.2ZnO0.8/Au photodetectors. The built-in electric field of the p-n heterojunction significantly suppresses the dark current and improves the responsivity. Remarkably, in the self-supply voltage detection mode, the heterojunction achieves a high responsivity of up to 1.1 mA/W. The dark current of the CH3NH3PbI3/Au/Mg0.2Zn0.8O heterojunction self-powered photodetectors is less than 1.4 × 10-1 pA at 0 V, which is more than 10 times lower than that of the CH3NH3PbI3 photodetectors. The best value of the detectivity is as high as 4.7 × 1012 Jones. Furthermore, the heterojunction self-powered photodetectors exhibit a uniform photodetection response over a wide spectral range from 200 to 850 nm. This work provides guidance for achieving a low dark current and high detectivity for perovskite photodetectors.
RESUMEN
Ultraviolet (UV) communication is a cutting-edge technology in communication battlefields, and self-powered photodetectors as their optical receivers hold great potential. However, suboptimal charge utilization has largely limited the further performance enhancement of self-powered photodetectors for high-throughput communication application. Herein, a self-powered Ti3 C2 Tx -hybrid poly(3,4 ethylenedioxythiophene):poly-styrene sulfonate (PEDOT:PSS)/ZnO (TPZ) photodetector is designed, which aims to boost charge utilization for desirable applications. The device takes advantage of photothermal effect to intensify pyro-photoelectric effect as well as the increased conductivity of the PEDOT:PSS, which significantly facilitated charge separation, accelerated charge transport, and suppressed interface charge recombination. Consequently, the self-powered TPZ photodetector exhibits superior comprehensive performance with high responsivity of 12.3 mA W-1 and fast response time of 62.2 µs, together with outstanding reversible and stable cyclic operation. Furthermore, the TPZ photodetector has been successfully applied in an integrated UV communication system as the self-powered optical receiver capable of real-time high-throughput information transmission with ASCII code under 9600 baud rate. This work provides the design insight of highly performing self-powered photodetectors to achieve high-efficiency optical communication in the future.
RESUMEN
The interface between the perovskite and electron-transporting material is often treated for defect passivation to improve the photovoltaic performance of devices. A facile 4-Acetamidobenzoic acid (containing an acetamido, a carboxyl, and a benzene ring)-based molecular synergistic passivation (MSP) strategy is developed here to engineer the SnOx /perovskite interface, in which dense SnOx are prepared using an E-beam evaporation technology while the perovskite is deposited with vacuum flash evaporation deposition method. MSP engineering can synergistically passivate defects at the SnOx /perovskite interface by coordinating with Sn4+ and Pb2+ with functional group CO in the acetamido and carboxyl. The optimized solar cell devices can achieve the highest efficiency of 22.51% based on E-Beam deposited SnOx and 23.29% based on solution-processed SnO2 , respectively, accompanied by excellent stability exceeding 3000 h. Further, the self-powered photodetectors exhibit a remarkably low dark current of 5.22 × 10-9 A cm-2 , a response of 0.53 A W-1 at zero bias, a detection limit of 1.3 × 1013 Jones, and a linear dynamic range up to 80.4 dB. This work proposes a molecular synergistic passivation strategy to enhance the efficiency and responsivity of solar cells and self-powered photodetectors.
RESUMEN
Organic-inorganic hybrid perovskite materials have been focusing more attention in the field of self-powered photodetectors due to their superb photoelectric properties. However, a universal growth approach is required and challenging to realize vertically oriented growth and grain boundary fusion of 2D and 3D perovskite grains to promote ordered carrier transport, which determines superior photoresponse and high stability. Herein, a general thermal-pressed (TP) strategy is designed to solve the above issues, achieving uniaxial orientation and single-grain penetration along the film thickness direction. It constructs the efficient channel for ordered carrier transport between two electrodes. Combining of the improved crystal quality and lower trap-state density, the quasi-2D and 3D perovskite-based self-powered photodetector devices (with/without hole transport layer) all exhibit giant and stable photoresponse in a wide spectrum range and specific wavelength laser. For the MAPbI3-based self-powered photodetectors, the largest Rλ value is as high as 0.57 A W-1 at 760 nm, which is larger than most reported results. Meanwhile, under laser illumination (532 nm), the FPEA2MA4Pb5I16-based device exhibits a high responsivity (0.4 A W-1) value, which is one of the best results in 2DRP self-powered photodetectors. In addition, fast response, ultralow detection limit, and markedly improved humidity, optical and heat stabilities are clearly demonstrated for these TP-based devices.
RESUMEN
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 93 mA W-1 accompanied by a detectivity (D*) of 3.1 × 1010 Jones are observed under self-driven conditions, when the device is exposed to 405 nm excitation laser wavelength, with a laser power density of 36 mW cm-2 and at a chopper frequency of 400 Hz. 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.
RESUMEN
Self-powered broadband photodetectors have attracted great interest due to their applications in biomedical imaging, integrated circuits, wireless communication systems, and optical switches. Recently, significant research is being carried out to develop high-performance self-powered photodetectors based on thin 2D materials and their heterostructures due to their unique optoelectronic properties. Herein, a vertical heterostructure based on p-type 2D WSe2and n-type thin film ZnO is realized for photodetectors with a broadband response in the wavelength range of 300-850 nm. Due to the formation of a built-in electric field at the WSe2/ZnO interface and the photovoltaic effect, this structure exhibits a rectifying behavior with a maximum photoresponsivity and detectivity of â¼131 mA W-1and â¼3.92 × 1010Jones, respectively, under an incident light wavelength ofλ= 300 nm at zero voltage bias. It also shows a 3-dB cut-off frequency of â¼300 Hz along with a fast response time of â¼496µs, making it suitable for high-speed self-powered optoelectronic applications. Furthermore, the facilitation of charge collection under reverse voltage bias results in a photoresponsivity as high as â¼7160 mA W-1and a large detectivity of â¼1.18 × 1011Jones at a bias voltage of -5 V. Hence, the p-WSe2/n-ZnO heterojunction is proposed as an excellent candidate for high-performance, self-powered, and broadband photodetectors.
RESUMEN
Self-powered photodetectors have attracted widespread attention due to their low power consumption which can be driven by the built-in electric field instead of external power, but it is very difficult to achieve high responsivity and fast response speed concurrently. Here, a self-powered photodetector with light-induced electric field enhancement based on a 2D InSe/WSe2 /SnS2 van der Waals heterojunction is designed. The light-induced electric field derived from the photo-generated electrons of SnS2 accumulated at the SnS2 /WSe2 interface produces an additional negative gate voltage applied to the WSe2 layer, which enhances the built-in electric field in the InSe/WSe2 /SnS2 heterojunction. Accordingly, the photocurrent and photoresponse speed of the heterostructure device are largely improved. The self-powered photodetector based on the InSe/WSe2 /SnS2 heterostructure exhibits a high responsivity of 550 mA W-1 , which is a 50 times increase compared to the InSe/WSe2 photodetector, and the response speed (110/120 µs) is one order of magnitude faster than that of the InSe/WSe2 photodetector. The high responsivity and fast speed are caused by the stronger built-in electric field modulated by a light-induced electric field, which can separate carriers effectively and reduce drift times. This device architecture can provide a new avenue to fabricate high-responsivity, fast self-power photodetectors by utilizing the van der Waals heterojunction.
RESUMEN
Organic materials exhibit efficient light absorption and low-temperature, large-scale processability, and have stimulated enormous research efforts for next-generation optoelectronics. While, high-performance organic devices with fast speed and high responsivity still face intractable challenges, due to their intrinsic limitations including finite carrier mobility and high exciton binding energy. Here an ultrafast and highly sensitive broadband phototransistor is demonstrated by integrating high-quality pentacene single crystal with monolayer graphene. Encouragingly, the -3 dB bandwidth can reach up to 26 kHz, which is a record-speed for such sensitized organic phototransistors. Enormous absorption, long exciton diffusion length of pentacene crystal, and efficient interfacial charge transfer enable a high responsivity of >105 A W-1 and specific detectivity of >1011 Jones. Moreover, self-powered weak-light detection is realized using a simple asymmetric configuration, and the obvious zero-bias photoresponses can be displayed even under 750 nW cm-2 light intensity. Excellent response speed and photoresponsivity enable high-speed image sensor capability in UV-Vis ranges. The results offer a practical strategy for constructing high-performance self-powered organic hybrid photodetectors, with strong applicability in wireless, weak-light detection, and video-frame-rate imaging applications.
RESUMEN
Realizing omnidirectional self-powered photodetectors is central to advancing next-generation portable and smart photodetector systems. However, the traditional omnidirectional photodetector is typically achieved by integrating complex hemispherical microlens on multiple photodetectors, which makes the detection system cumbersome and restricts its application in the portable field. Here, facile and high-performance flexible omnidirectional self-powered photodetectors are achieved by solution-processed two-dimensional (2D) layered PbI2 nanoplates on transparent conducting substrates. Characterization of PbI2 nanoplates microstructural/compositional and their photodetection properties have been systematically characterized. Under the irradiation of a 405 nm laser, the photodetectors exhibit an impressively low dark current of 10-13 A, a high light on/off ratio up to 106, and a fast rise/decay response time of 2/3 ms. Importantly, when light irradiates the photodetector at 5°, it can still maintain high photodetection properties, realizing almost 360° omnidirectional self-powered photodetection. What is more, these self-powered photodetectors exhibit robust omnidirectional photoresponse stability of flexibility even after bending for 1200 cycles. Thus, this work broadens the applicability of 2D layered nanoplates for further extending its applications in advanced optoelectronic devices.
RESUMEN
Thin-film lithium niobate platform, namely lithium-niobate-on-insulator (LNOI), brings new opportunities for integrated photonics, taking advantages from both outstanding crystalline properties and special structural features. The excellent properties of LNOI have triggered development of a variety of on-chip photonic devices for light generation and manipulation. However, as an indispensable component for photonic circuit with full functionalities, the thin-film photodetector lacks in portfolios of LNOI-based devices due to standing obstacles of low electrical conductivity and poor photoelectric conversion ability. Here, a self-powered broadband LNOI photodetector based on enhanced photovoltaic effect, benefitting from encapsulated plasmonic nanoparticles and doped silver ions, is reported. Maximum responsivity of 0.25 A W-1 and detectivity (1.56 × 1014 Jones) are achieved. First-principle calculations and electric-field simulation reveal intrinsic mechanisms and crucial roles of plasmonic nanoparticles and silver ions on photocurrent generation and collection. This work opens an avenue to develop high-performance on-chip LNOI photodetectors, offering a conceivable means toward multiple-functional photonic circuits.