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Asymmetric Contact Induced Self-Powered 2D In2S3 Photodetector towards High-Sensitivity and Fast-Response
摘要： Self-powered photodetectors have triggered extensive attention in recent years due to the advantages of high sensitivity, fast response, low power consumption, high level of integration and wireless operation. To date, most self-powered photodetectors are implemented through the construction of either heterostructures or asymmetric electrode material contact, which are complex to process and costly to produce. Herein, for the first time, we achieve self-powered operation by adopting geometrical asymmetry in the device architecture, where a triangular non-layered 2D In2S3 flake with asymmetric contact is combined with traditional photogating effect. Importantly, the device achieves excellent photoresponsivity (740 mA/W), high detectivity (1.56 × 1010 Jones), and fast response time (9/10 ms) under zero bias. Furthermore, the asymmetric In2S3/Si photodetector manifests long-term stability. Even after 1000 cycles of operation, the asymmetric In2S3/Si device displays negligible performance degradation. In sum, the above results highlight a novel route towards self-powered photodetectors with high performance, simple processing and structure in the future.
关键词： high sensitivity,fast response,asymmetric contact,Self-powered photodetectors,2D In2S3,photogating effect
更新于2025-09-19 17:13:59
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Solution-processed one-dimensional CsCu <sub/>2</sub> I <sub/>3</sub> nanowires for polarization-sensitive and flexible ultraviolet photodetectors
摘要： Polarization-sensitive ultraviolet (UV) photodetectors are highly desired due to their great significance in many applications. As the newly-emerging functional semiconductors, the metal-halide perovskites have attracted huge attention in photodetection due to their excellent optoelectronic features. However, the ever-reported perovskites polarized photodetectors mainly focused on the visible/infrared-light region, and the devices targeted at the UV region have not been reported. Here, for the first time, ternary copper halides CsCu2I3 nanowire was used as the light absorber to achieve polarization-sensitive UV photodetection. By combining the intrinsic anisotropy of the asymmetry structure and external morphology anisotropy of CsCu2I3 nanowires, a record photocurrent anisotropy ratio of ~3.16 was achieved, and also the shortcomings of lead-toxicity and environmental instability for conventional lead-halide perovskites were overcome effectively. Moreover, such photodetectors fabricated on flexible substrate demonstrate good flexibility and stability, showing almost no photoresponse degradation after extremely bending for 1000 cycles. The results suggest that the lead-free CsCu2I3 nanowire is potentially an attractive candidate for high-performance polarization-sensitive UV photodetectors compatible for practical applications.
关键词： CsCu2I3 nanowires,Polarization-sensitive,metal-halide perovskites,lead-free,ultraviolet photodetectors,flexible substrate
更新于2025-09-19 17:13:59
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Mixed-dimensional self-assembly organica??inorganic perovskite microcrystals for stable and efficient photodetectors
摘要： The unstability of organic-inorganic perovskites in humid air is a serious bottleneck that restricts their practical applications in optoelectronics, although tremendous achievements have been scored in organic-inorganic perovskite devices. Materials engineering is believed to be one of the most direct strategy to address this issue. Mixed-dimensional organic-inorganic perovskite microcrystals, which have the advantage of relatively good charge carrier transport owing to limited grain boundaries and low defect densities compared to perovskite thin films, integrate the good humidity stability of two-dimensional (2D) and single-phase quasi-2D perovskites and the high photoresponse of 3D perovskites in an individual crystal, rendering them an excellent candidate for the development of high-performance photodetectors. Herein, the (C6H5CH2CH2NH3, PEA)2(CH3NH3, MA)n-1PbnBr3n+1 (n = 1, 3, 5, ∞ ) perovskite microcrystals have been synthesized using an anti-solvent vapor-assisted method, and the optoelectronic properties of these microcrystals are investigated by fabricating photodetectors in a lateral configuration. The (PEA)2(MA)2Pb3Br10 and (PEA)2(MA)4Pb5Br16 perovskites are proved to be mixed-dimensional microcrystals, respectively, which consist of the single phases of 2D (PEA)2PbBr4, quasi-2D perovskite, and 3D MAPbBr3. The photodetectors based on the individual (PEA)2(MA)2Pb3Br10 and (PEA)2(MA)4Pb5Br16 perovskite microcrystals show better performances than the (PEA)2PbBr4 microcrystal photodetector, and exhibit higher humidity resistance than the MAPbBr3 device. The best performances are achieved in the (PEA)2(MA)4Pb5Br16 microcrystal photodetector with a high responsivity of 182.63A/W, detectivity of 2.51×1014 Jones, and gain of 5.58×102, which can detect an optical signal with an extremely low light power density of 2.47 nW/cm2. Our results demonstrate that developing mixed-dimensional perovskite microcrystals is a promising way to construct highly efficient and stable photodetectors.
关键词： organic-inorganic perovskites,stable and efficient photodetectors,mixed-dimensional microcrystals,humidity stability
更新于2025-09-19 17:13:59
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Heavy-Metal-Free Flexible Hybrid Polymer-Nanocrystal Photodetectors Sensitive to 1.5-μm-wavelength
摘要： Photodetection in the short-wave infrared (SWIR) wavelength window represents one of the core technologies allowing for many applications. Most current photodetectors suffer from high cost due to the epitaxial growth requirements and the ecological issue due to the use of highly toxic heavy-metal elements. Toward an alternative SWIR photodetection strategies, in this work, high-performance heavy-metal-free flexible photodetectors sensitive to λ = 1.5 μm photons are presented based on the formation of a solution-processed hybrid composing of a conjugated diketopyrrolopyrrole-base polymer/PC70BM bulk heterojunction organic host together with inorganic guest NaYF4:15%Er3+ upconversion nanoparticles (UCNPs). Under the illumination of λ = 1.5 μm SWIR photons, optimized hybrid BHJ/UCNP photodetectors exhibit a photoresponsivity of 0.73 mA/W and 0.44 mA/W respectively for devices built on rigid ITO/glass and flexible ITO/polyethylene terephthalate (PET) substrates. These hybrid photodetectors are capable of performing SWIR photodetection with a fast operation speed, characterized by a short photocurrent rise time down to 80 μs, together with an excellent mechanical robustness for flexible applications. Exhibiting simultaneously multiple advantages including solution-processability, flexibility, and the absence of toxic heavy metal elements together with a fast operation speed and good photoresponsivity, these hybrid BHJ(DPPTT-T/PC70BM)/UCNP photodetectors are promising candidates for next-generation low-cost and high-performance SWIR photodetectors.
关键词： nanocrystals,short-wave infrared,flexible,solution process,hybrid photodetectors
更新于2025-09-19 17:13:59
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MXene Enhanced Deep Ultraviolet Photovoltaic Performances of Crossed Zn <sub/>2</sub> GeO <sub/>4</sub> Nanowires
摘要： Zn2GeO4 crystal is an ideal semiconductor for deep ultraviolet detection due to its wide-bandgap of ~4.69 eV. To further improve its DUV performance, two-dimensional MXenes with high electrical conductivity, potentially tunable electronic structure and nonlinear optical properties were applied on crossed Zn2GeO4 nanowires network materials. The results presented here show that the DUV detectors based on Zn2GeO4/MXene hybrid nanostructure exhibited excellent optoelectronic performances with a largest responsivity of 20.43 mA/W and external quantum efficiency of 9.9% under 254 nm wavelength light illumination. The excellent optical performance is from the synergistic effect of MXene and Zn2GeO4 nanowires. The metallic property of MXene provide a fast electron-transport for Zn2GeO4/MXene, which leads to larger photocurrent and fast photo response. The construction of unique semiconductive-conductive networks and large interfaces of Zn2GeO4 NWs, MXene layers, and the interfaces between them also promotes photo-induced electron-hole separation in the sample. Considering the large amount of members in MXene, this study demonstrates a new strategy applicable in maximizing their applications in deep ultraviolet photodetectors.
关键词： photodetectors,nanowires,deep ultraviolet,Zn2GeO4,MXene
更新于2025-09-19 17:13:59
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Non-layered ZnSb nanoplates for room temperature infrared polarized photodetectors
摘要： Non-layered 2D ZnSb nanoplates are successfully synthesized by chemical vapor deposition, which possess narrow band gap and novel anisotropic properties. Infrared polarized photodetectors based on the ZnSb nanoplates are designed and exhibit high responsivity, fast photoresponse speed, great stability, high anisotropic conductivity and linear polarization sensitivity.
关键词： anisotropic properties,ZnSb nanoplates,narrow band gap,chemical vapor deposition,infrared polarized photodetectors
更新于2025-09-19 17:13:59
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Frequency- and Power-Dependent Photoresponse of a Perovskite Photodetector Down to the Single-Photon Level
摘要： Organometallic halide perovskites attract strong interests for their high photoresponsivity and solar cell efficiency. However, there was no systematic study of their power and frequency dependent photoresponsivity. We identified two different power-dependent photoresponse types in methylammonium lead iodide perovskite (MAPbI3) photodetectors. In the first type, photoresponse remains constant from 5 Hz to 800 MHz. In the second type, absorption of a single photon can generate a persistent photoconductivity of 30 pA under an applied electric field of 2.5×104 V/cm. Additional absorbed photons, up to 8, linearly increase the persistent photoconductivity, which saturates with absorption of more than 10 photons. This is different than single photon avalanche detectors (SPADs) because the single photon response is persistent as long as the device is under bias, providing unique opportunities for novel electronic and photonic devices such as analog memories for neuromorphic computing. We propose an avalanche-like process for iodine ions and estimate that absorption of a single 0.38 aJ photon triggers motion of 108-9 ions, resulting in accumulations of ions and charged vacancies at the MAPbI3/electrode interfaces to cause band bending and change of material electric properties. We have made the first observation that single-digit photon absorption can alter the macroscopic electric and optoelectronic properties of a perovskite thin film.
关键词： Perovskite,photodetectors,impact ionization,ion migration,single photon sensitivity
更新于2025-09-19 17:13:59
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Ultrafast Photodetector by Integrating Perovskite Directly on Silicon Wafer
摘要： Single crystal (SC) perovskite is currently a promising material due to its high quantum efficiency and long diffusion length. However, the reported perovskite photodection range (< 800 nm) and response time (> 10 μs) are still limited. Here, to promote the development of perovskite-integrated optoelectronic devices, this work demonstrates wider photodection range and shorter response time perovskite photodector by integrating the SC CH3NH3PbBr3 (MAPbBr3) perovskite on silicon (Si). The Si/MAPbBr3 heterojunction photodetector with an improved interface exhibits high performances including high speed, broad spectrum, and long-term stability. To our best knowledge, the measured detectable spectrum (405 nm-1064 nm) largely expands the widest response range reported in previous perovskite-based photodetectors. In addition, the rise time is as fast as 520 ns, which is comparable with commercial germanium photodetectors. Moreover, the Si/MAPbBr3 device can maintain excellent photo-current performance up to 3 months. Furthermore, typical grey-scale face imaging is realized by scanning the Si/MAPbBr3 single-pixel photodetector. This work of ultrafast photodetector by directly integrating perovskite on Si can promote advances in next-generation integrated optoelectronic technology.
关键词： photodetectors,integrations,single crystal perovskites,CH3NH3PbBr3,ultrafast
更新于2025-09-19 17:13:59
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High performance flexible organic photomultiplication photodetector based on ultra-thin silver film transparent electrode
摘要： Flexible and lightweight photomultiplication-type organic photodetectors (PM-OPDs) have attracted wide attention for their broad application prospects, especially in the field of wearable electronic products. However, the common used indium tin oxide (ITO) conductive anode is not conducive to realize high-performance flexible PM-OPD due to its rigidity and fragility. Here, on the flexible polyethylene terephthalate (PET) substrate, we successfully fabricate highly sensitive poly 3-hexylthiophene:phenyl-C70-butyric acid methyl ester (P3HT:PC70BM, 100:1) based PM-OPDs using ultra-thin silver films as the transparent anode. Specifically, a 1 nm thick MoO3 layer is utilized as the wetting layer for facilitating the silver film percolation, and a 2 nm thick MoO3 layer, as the hole transport layer, is coated on top of the ultra-thin silver film before coating the P3HT:PC70BM film. The as-prepared flexible PM-OPDs based on the ultra-thin silver film exhibit the optimal external quantum efficiency (EQE) and responsivity (R) of 1.3×105 % and 388.4 A/W, respectively, under -15 V bias, which are 1.98 times and 2.15 times greater than those of the ITO anode based device. More importantly, the device has good flexibility with the EQE maintaining 70.6% of its initial value after 10 times of bending, and 51.4% of its initial value after 1000 times of bending. This work paves the way for developing flexible PM-OPDs as well as other flexible optoelectronic devices.
关键词： multiplication,transparent electrode,photodetectors,silver film,flexible
更新于2025-09-19 17:13:59
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Enhanced Ona??Off Ratio Photodetectors Based on Leada??Free Cs <sub/>3</sub> Bi <sub/>2</sub> I <sub/>9</sub> Single Crystal Thin Films
摘要： Hybrid organic–inorganic lead halide perovskite single crystal thin film (SCTF) recently has attracted enormous interest in the field of optoelectronic devices, since it efficiently resolves the trade-off between thickness and carrier diffusion length. However, the toxicity of lead element and the instability induced by organic component still hinder its future developments. In this work, lead-free all-inorganic Cs3Bi2I9 SCTF with a high orientation along (00h) has been in situ grown on indium tin oxide (ITO) glass via a space-limited solvent evaporation crystallization method. The trap density of Cs3Bi2I9 SCTF (5.7 × 1012 cm?3) is 263 folds lower than that of the polycrystalline thin film (PCTF) counterpart, together with a 5-order-of-magnitude higher carrier mobility. These superior charge transfer properties enable a photoresponse on–off ratio as high as 11 000, which far surpasses that of the PCTF device by 460 folds, comparable to the lead halide perovskite. Furthermore, the Cs3Bi2I9 SCTF photodetector exhibits outstanding stability even without any encapsulation, whose initial performance is well maintained after aging 1000 h in humid air of 50% RH or continuous on–off light illumination for 20 h. This work will pave the way to produce new families of high-performance, stable, and nontoxic perovskite SCTF for future optoelectronic applications.
关键词： stability,photodetectors,perovskites,Cs3Bi2I9,single crystal thin films
更新于2025-09-19 17:13:59