- 标题
- 摘要
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- 实验方案
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Organic Photodetectors: Materials, Structures, and Challenges
摘要： Owing to the advantages of solution processing, light weight, low cost and mechanical flexibility, organic photodetectors (OPDs) have attracted great interests and become a new member in the photodetector family. Nowadays, OPDs have made considerable progress and can be compared with traditional photodetectors in some aspects. They present potential applications in portable and wearable devices. However, there are still some issues that need to be overcome and there is great room for new development. In this essay, the significant advances of OPDs are summarized and discussed, and the future for OPDs is prospected from the aspects of materials, structures and applications. We believe that this essay can inspire new ideas for developing innovative high-performance OPDs and exploring their practical applications.
关键词： materials,organic photodetectors,structures,applications
更新于2025-09-23 15:19:57
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Interface Engineering Assisted 3D-Graphene/Germanium Heterojunction for High-Performance Photodetectors
摘要： Three-dimensional graphene (3D-Gr) with excellent light absorption properties has received enormous interest but in conventional processes to prepare 3D-Gr, amorphous carbon layers are inevitably introduced as buffer layers which may degrade the performance of graphene-based devices. Herein, 3D-Gr is prepared on germanium (Ge) using two-dimensional graphene (2D-Gr) as the buffer layer. 2D-Gr as the buffer layer facilitates in-situ synthesis of 3D-Gr on Ge by plasma-enhanced chemical vapor deposition (PECVD) by promoting 2D-Gr nucleation and reducing the barrier height. The growth mechanism is investigated and described. The enhanced light absorption as confirmed by theoretical calculation and 3D-Gr/2D-Gr/Ge with a Schottky junction improves the performance of optoelectronic devices without requiring pre- and post-transfer processes. The photodetector constructed with 3D-Gr/2D-Gr/Ge shows an excellent responsivity of 1.7 AW-1 and detectivity 3.42 × 1014 cmHz1/2W?1 at a wavelength of 1,550 nm. This novel hybrid structure which incorporates 3D- and 2D-Gr into Ge-based integrated circuits and photodetectors deliver excellent performance and has large commercial potential.
关键词： Buffer layer,Germanium,Photodetectors,Built-in potential,3D/2D-graphene
更新于2025-09-23 15:19:57
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Aira??Stable Highly Crystalline Formamidinium Perovskite 1D Structures for Ultrasensitive Photodetectors
摘要： State-of-the-art optoelectronic devices based on metal-halide perovskites demand solution-processed structures with high crystallinity, controlled crystallographic orientation, and enhanced environmental stability. Formamidinium lead iodide (α-FAPbI3) possesses a suitable bandgap of 1.48 eV and enhanced thermal stability, whereas perovskite-type polymorph (α-phase) is thermodynamically instable at ambient temperatures. Stable α-FAPbI3 perovskite 1D structure arrays with high crystallinity and ordered crystallographic orientation are developed by controlled nucleation and growth in capillary bridges. By surface functionalization with phenylethylammonium ions (PEA+), FAPbI3 wires sustain a stable α-phase after 28 day storage in the ambient environment with a relative humidity of 50%. Enhanced photoluminescence (PL) intensity and elongated PL lifetime demonstrate suppressed trap density and high crystallinity in these 1D structures, which is also reflected by the enhanced diffraction density and pure (001) crystallographic orientation in the grazing-incidence wide-angle X-ray scattering (GIWAXS) pattern. Based on these high-quality 1D structures, sensitive photodetectors are achieved with average responsivities of 5282 A W?1, average specific detectivities of more than 1.45 × 1014 Jones, and a fast response speed with a 3 dB bandwidth of 15 kHz.
关键词： metal-halide perovskites,1D structures,photodetectors,α-FAPbI3
更新于2025-09-23 15:19:57
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Improved Photoresponse of UV Photodetectors by the Incorporation of Plasmonic Nanoparticles on GaN Through the Resonant Coupling of Localized Surface Plasmon Resonance
摘要： Very small metallic nanostructures, i.e., plasmonic nanoparticles (NPs), can demonstrate the localized surface plasmon resonance (LSPR) effect, a characteristic of the strong light absorption, scattering and localized electromagnetic field via the collective oscillation of surface electrons upon on the excitation by the incident photons. The LSPR of plasmonic NPs can significantly improve the photoresponse of the photodetectors. In this work, significantly enhanced photoresponse of UV photodetectors is demonstrated by the incorporation of various plasmonic NPs in the detector architecture. Various size and elemental composition of monometallic Ag and Au NPs, as well as bimetallic alloy AgAu NPs, are fabricated on GaN (0001) by the solid-state dewetting approach. The photoresponse of various NPs are tailored based on the geometric and elemental evolution of NPs, resulting in the highly enhanced photoresponsivity of 112 A W?1, detectivity of 2.4 × 1012 Jones and external quantum efficiency of 3.6 × 104% with the high Ag percentage of AgAu alloy NPs at a low bias of 0.1 V. The AgAu alloy NP detector also demonstrates a fast photoresponse with the relatively short rise and fall time of less than 160 and 630 ms, respectively. The improved photoresponse with the AgAu alloy NPs is correlated with the simultaneous effect of strong plasmon absorption and scattering, increased injection of hot electrons into the GaN conduction band and reduced barrier height at the alloy NPs/GaN interface.
关键词： UV photodetection,NP-based photodetectors,Plasmonic enhancement,Nanoparticles
更新于2025-09-23 15:19:57
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A simple route for manufacture of photovoltaic devices based on chalcohalide nanowires
摘要： The one-dimensional nanostructures of antimony sulfoiodide (SbSI) have received in last decade a great attention due to their outstanding photoferroelectric properties combined with narrow energy band gap beneficial for effective conversion of visible light into electric signal. This paper reports for the first time a simple and fast route for fabrication of photovoltaic devices based on SbSI nanowires. This method involves sonochemical synthesis of SbSI nanowires and spin-coating SbSI-polyacrylonitrile (PAN) composite, on indium tin oxide (ITO) substrate. In order to promote efficient charge transfer titanium dioxide (TiO2) and poly(3-hexylthiophene) (P3HT) were applied as an electron and hole transporting layers, respectively. Proposed method can be realized at mild conditions and does not require any additional high temperature treatment in contrast to other methods known for fabrication of SbSI photovoltaic structures. Fabricated structures exhibited an average short-circuit current density of 1.84(20) μA/cm2 and open circuit voltage of 69(13) mV under a white light illumination with power density of 100 mW/cm2. SbSI nanowires as lead-free nanomaterials are promising for solar energy harvesting and an application in photodetectors, that can operate in self-powered mode.
关键词： Nanocomposite,Self-powered photodetectors,Nanowires,Polyacrylonitrile (PAN),Antimony sulfoiodide (SbSI),Photovoltaic devices
更新于2025-09-23 15:19:57
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High-responsivity turbostratic stacked graphene photodetectors using enhanced photogating
摘要： High-responsivity graphene photodetectors were fabricated using turbostratic stacked graphene, which provided enhanced photogating. Photogating is a promising means of increasing the responsivity of graphene photodetectors, and this effect is proportional to carrier mobility. Turbostratic stacked graphene exhibits higher carrier mobility than conventional monolayer graphene because it has the same band structure as monolayer graphene while preventing scattering by the underlying SiO2 layer. The photoresponse of these devices at a wavelength of 642 nm was approximately twice that obtained for a conventional monolayer graphene photodetector. The results reported show the feasibility of producing high-responsivity graphene-based photodetectors using a simple fabrication technique.
关键词： turbostratic stacked graphene,photogating,photodetectors,graphene,carrier mobility
更新于2025-09-23 15:19:57
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Graphene/GaAs heterojunction for highly sensitive, self-powered Visible/NIR photodetectors
摘要： Graphene/GaAs heterojunction has been demonstrated by transferring monolayer graphene on the surface of n-GaAs substrate, and the carrier transfer at the interface has been investigated by monitoring Raman shift of graphene on different substrates. The photovoltaic behavior and rectifying characteristic of the graphene/GaAs heterojunctions enable us to fabricate high-performance self-powered photodetector at zero bias. The device has been demonstrated to be sensitive to visible/near-infrared light (405–850 nm) at room temperature, giving rise to maximum responsivity of 122 mA W?1 and detectivity of 4.3 × 1012 Jones with quick response and recover time (0.5 ms and 0.35 ms), respectively. Such high photoelectric response is attributed to the efficient photo-generated carrier separation and transfer at the interface, which is caused by the strong built-in electric field between grapheme and GaAs because of a large barrier (0.87 eV). Our results confirm that the graphene/GaAs heterojunction has a great potential for high performance self-powered broadband photodetectors.
关键词： Photodetectors,Raman shift,Heterojunction,Graphene,Charge transfer
更新于2025-09-23 15:19:57
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Composition and size controlled I-V-VI semiconductor nanocrystals
摘要： Non-isovalent ternary and quaternary semiconductors (i.e., having two or more cations with different valence) have unique structural and electronic properties that are leveraged in photovoltaic, thermoelectric, and phase-change memory devices. Making these complex semiconductors in the form of colloidal nanocrystals imparts size-dependent properties and solution processability. Here, we present results on I‐V‐VI group colloidal nanocrystals. We focus on achieving sub-10 nm sizes for a wide range of I-V-VI selenide nanocrystals, including AgSbSe2, AgSb2Se3, CuSbSe2, Cu3SbSe4, AgBiSe2, and CuBiSe2. To highlight one possible application for these I-V-VI colloidal nanomaterials, we analyze the optical absorption and show that through composition and size control, this class of materials offers bandgaps in the mid- to near-IR. Absorption coefficients of AgSbSe2, CuSbSe2, and Cu3SbSe4 nanocrystals are on par with or higher than the well-studied PbS nanocrystals highlighting their potential for devices such as solar cells, (mid-)infrared photodetectors, and near-infrared bio-imaging systems.
关键词： solar cells,optical absorption,bio-imaging systems,colloidal nanocrystals,infrared photodetectors,mid- to near-IR,I-V-VI semiconductor nanocrystals,bandgaps
更新于2025-09-23 15:19:57
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Realizing high detectivity organic photodetectors in visible wavelength by doping highly ordered polymer PCPDTBT
摘要： A new method for realizing the response broadening of organic photodetectors (OPDs) using highly ordered polymer PCPDTBT doping has been proposed in this paper. The effects of PCPDTBT doping on the optical and electrical properties of OPDs were investigated experimentally. It was found that when the mass ratio of PTB7:PCPDTBT:PC61BM was 8.5:1.5:15, the response spectrum of the OPDs was broadened to 380–830 nm. The responsivity (R) and external quantum efficiency (EQE) of the OPDs reached 396, 244, 189 mA/W and 78%, 57%, 51% under 630, 530 and 460 nm illumination and (cid:0) 1 V bias, respectively, and the detectivity (D*) reached 1011 Jones. The results showed that the addition of PCPDTBT to PTB7:PC61BM increased the absorption of light at 700–830 nm. At the same time, the addition of PCPDTBT promotes the exciton dissociation interface in the active layer from the original one to the current three, they are PTB7:PCPDTBT, PTB7:PC61BM and PCPDTBT:PC61BM, which increase the probability of exciton dissociation in the active layer. In addition, the addition of highly ordered polymer PCPDTBT promotes the crystallization of the film and optimizes the carrier transport of the film. These synergistic effects promote the photocurrent of the OPDs.
关键词： Ternary bulk heterojunction,Exciton dissociation,Organic photodetectors,Microscopic morphology
更新于2025-09-23 15:19:57
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Near full light absorption and full charge collection in 1-micron thick quantum dot photodetector using intercalated graphene monolayer electrodes
摘要： Quantum dots (QDs) offer several advantages in optoelectronics such as easy solution processing, strong light absorption and size tunable direct bandgap. However, their major limitation is their poor film mobility and short diffusion length (<250 nm). This has restricted the thickness of QD film to ～200–300 nm due to the restriction that the diffusion length imposes on film thickness in order to keep efficient charge collection. Such thin films result in a significant decrease in quantum efficiency for λ > 700 nm in QDs photodetector and photovoltaic devices, causing a reduced photoresponsivity and a poor absorption towards the near-infrared part of the sunlight spectrum. Herein, we demonstrate 1 μm thick QDs photodetectors with intercalated graphene charge collectors that avoid the significant drop of quantum efficiency towards λ > 700 nm observed in most QD optoelectronic devices. The 1 μm thick intercalated QD films ensure strong light absorption while keeping efficient charge extraction with a quantum efficiency of 90%–70% from λ = 600 nm to 950 nm using intercalated graphene layers as charge collectors with interspacing distance of 100 nm. We demonstrate that the effect of graphene on light absorption is minimal. We achieve a time-modulation response of <1 s. We demonstrate that this technology can be implemented on flexible PET substrates, showing 70% of the original performance after 1000 times bending test. This system provides a novel approach towards high-performance photodetection and high conversion photovoltaic efficiency with quantum dots and on flexible substrates.
关键词： Optoelectronics,Photodetectors,Quantum dots,Graphene,Flexible substrates
更新于2025-09-23 15:19:57