- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Ligand Engineering for Improved All‐Inorganic Perovskite Quantum Dot‐MoS <sub/>2</sub> Monolayer Mixed Dimensional van der Waals Phototransistor
摘要： Combining intriguing physical properties of 2D crystals and intrinsically remarkable optical properties of halide perovskite quantum dots (QDs), the 0D–2D perovskite QD–based mixed dimensional van der Waals heterostructure (MvdWH) is considered as promising for optoelectronic applications. Even though the interfacial electronic structure of MvdWHs is sufficiently engineered to manipulate the charge carrier behavior, the issue of interfacial charge transfer efficiency originating from the residue ligands that are inevitably introduced by the QDs is still prominently remained. From this perspective, for the first time, a solution-processed surface ligand density control strategy is demonstrated to balance the QD surface passivation and the interfacial charge carrier extraction and injection efficiency in the 0D–2D MvdWH system. The accurate adjustment of ligand density outside QDs enables the subsequent modulation on interfacial charge carrier transfer efficiency from the aspect of electronic and optoelectronic properties. Furthermore, such kind of ligand engineering toward MvdWH interface is substantially demonstrated in a photogating mechanism–based phototransistor with an improved photoresponsivity as high as 1.13 × 105 A W?1. These results may push forward the evolution of 0D–2D mixed dimensional van der Waals optoelectronics.
关键词： mixed-dimensional van der Waals heterostructures,perovskite quantum dots,phototransistors,MoS2,ligand engineering
更新于2025-11-14 17:04:02
-
Characteristics of GeSn-based multiple quantum well heterojunction phototransistors: a simulation-based analysis
摘要： Introduction of multiple quantum wells (MQWs) is an efficient way to enhance the light absorption capability in phototransistors. Direct band gap Ge1?xSnx alloy (x?>?0.08) having large absorption coefficient is an attractive material for heterojunction phototransistors (HPTs) compatible with CMOS platform. In this work, simulations are employed to obtain current gain, responsivity and collector current characteristics of Ge/GeSn/Ge HPTs with incorporation of MQWs (Ge0.87Sn0.13/Ge0.83Sn0.17) in the base region. The performances of bulk, single quantum well and MQW HPT structures are examined and compared. Best performance is shown by HPTs having MQW structure over a wide range of base emitter voltage.
关键词： simulation,current gain,heterojunction phototransistors,responsivity,GeSn,multiple quantum wells
更新于2025-09-23 15:21:21
-
Enhanced UV-visible detection of InGaZnO phototransistors via CsPbBr3 quantum dots
摘要： Indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) exhibit high field-effect carrier mobility and low off-state current, which are attractive for high speed and low noise photodetectors and image sensor applications. However, with an optical band gap of ~3.3 eV, the photodetection range of IGZO TFTs is limited to short wavelength ultraviolet (UV) light. Here, we demonstrate a simple approach to enhance the performance of IGZO-based phototransistors by incorporating layers of solution-processed perovskite quantum dots (QDs) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). Owing to the fast transfer of photogenerated electrons by CsPbBr3 QDs absorbing layer, the photoresponse of QD-decorated IGZO phototransistor is extended to the visible range (500 nm), and the responsivity and detectivity of QD-decorated device are more than two order higher than those of original IGZO TFTs. Moreover, the QD-decorated IGZO phototransistor also exhibits enhanced performance under UV light (350 nm), achieving a responsivity of 9.72 A/W, a detectivity of 2.96 × 1012 Jones, and a light to dark current ratio in the order of 106 at a wavelength of 350 nm (a light intensity of 207.3 μW/cm2).
关键词： heterojunction,CsPbBr3 QDs,IGZO,phototransistors
更新于2025-09-23 15:19:57
-
Largea??Scale Ultrathin 2D Widea??Bandgap BiOBr Nanoflakes for Gatea??Controlled Deepa??Ultraviolet Phototransistors
摘要： Ternary two-dimensional (2D) semiconductors with controllable wide bandgap, high ultraviolet (UV) absorption coefficient, and critical tuning freedom degree of stoichiometry variation have a great application prospect for UV detection. However, as-reported ternary 2D semiconductors often possess a bandgap below 3.0 eV, which must be further enlarged to achieve comprehensively improved UV, especially deep-UV (DUV), detection capacity. Herein, sub-one-unit-cell 2D monolayer BiOBr nanoflakes (≈0.57 nm) with a large size of 70 μm are synthesized for high-performance DUV detection due to the large bandgap of 3.69 eV. Phototransistors based on the 2D ultrathin BiOBr nanoflakes deliver remarkable DUV detection performance including ultrahigh photoresponsivity (Rλ, 12739.13 A W?1), ultrahigh external quantum efficiency (EQE, 6.46 × 106%), and excellent detectivity (D*, 8.37 × 1012 Jones) at 245 nm with a gate voltage (Vg) of 35 V attributed to the photogating effects. The ultrafast response (τrise = 102 μs) can be achieved by utilizing photoconduction effects at Vg of ?40 V. The combination of photocurrent generation mechanisms for BiOBr-based phototransistors controlled by Vg can pave a way for designing novel 2D optoelectronic materials to achieve optimal device performance.
关键词： monolayer BiOBr,deep UV phototransistors,wide-bandgap semiconductors,high gain
更新于2025-09-23 15:19:57
-
Photodetectors based on solution-processable semiconductors: Recent advances and perspectives
摘要： The detection of light, one of the most important technologies, has widespread applications in industry and our daily life, e.g., environmental monitoring, communications, surveillance, image sensors, and advanced diagnosis. Along with the remarkable progress in the field of organics, those based on quantum dots, and recently emerged perovskite optoelectronics, photodetectors based on these solution-processable semiconductors have shown unprecedented success. In this review, we present the basic operation mechanism and the characterization of the performance metrics based on these novel materials systems. Then, we focus on the current research status and recent advances with the following five aspects: (i) spectral tunability, (ii) cavity enhanced photodetectors, (iii) photomultiplication type photodetectors, (iv) sensitized phototransistors, and (v) ionizing radiation detection. At the end, we discuss the key challenges facing these novel photodetectors toward manufacture and viable applications. We also point out the opportunities, which are promising to explore and may require more research activities.
关键词： sensitized phototransistors,photodetectors,cavity enhanced photodetectors,solution-processable semiconductors,photomultiplication type photodetectors,spectral tunability,ionizing radiation detection
更新于2025-09-23 15:19:57
-
High performance n-type vertical organic phototransistors
摘要： In this manuscript, a solution-processed n-type organic phototransistor based on vertical structure thin-film transistors was proposed. Due to the vertical structure and short channel length (≈130 nm), the transistors exhibited excellent current density (15.4 mA/cm2) with high Ion/Ioff ratio (up to 105). On account of this structure, the face-on π-π stacking of P(NDI2OD-T2) was aligned with the charge transport direction, which facilitated charge transfer from source to drain electrode. Moreover, n-type organic phototransistors based on vertical thin-film transistors were demonstrated for the first time, in which the active layer was protected by the source-drain electrodes, resulting in the improvement of the stability of the device. Due to the nanoscale channel, efficient separation of electron-hole pairs and quick charge transfer can be achieved. Hence, high-performance n-type phototransistor was obtained with responsivity of 34.8 A/W, photosensitivity of 4.78×104, detectivity of 3.95×1013 Jones and external quantum efficiency up to 1.1×104 % under 400 nm illumination with a light intensity of 200 μW cm-2, which was much better than those reported n-type organic phototransistors. This work provided a strategy for the fabrication of high performance n-type organic phototransistor, which paved the way for its future application in the next-generation organic optoelectronics.
关键词： n-type organic semiconductor,Organic phototransistors,Vertical structure,Organic thin-film transistors
更新于2025-09-19 17:15:36
-
NIR polymers and phototransistors
摘要： A novel bisthiophene-fused diketopyrrolopyrrole unit (4,11-bis(2-octyldodecyl)-7H,14H-thieno[30,20:7,8]indolizino[2,1-a]thieno[3,2-g]indolizine-7,14-dione, BTI) has been designed as an electron acceptor and used to copolymerize with thiophene and bithiophene as electron donors to construct two D–A conjugated polymers, P1 and P2 via Stille coupling, respectively. The two polymers showed excellent thermal stability, broad light absorption and a narrow energy band gap. P1 and P2 were used to fabricate organic field-effect transistors (OFETs) to evaluate their charge transport characteristics. P2 showed much better hole transport performance with a mobility of 0.1 cm2 V?1 s?1. Near-infrared (NIR) phototransistors were also fabricated by using the two polymers blended with PC71BM as the active layer. With illumination of 35 mW cm?2 at a wavelength of 850 nm, the photocurrent/dark-current ratio (P) and photoresponsivity (R) of the phototransistor based on P1/PC71BM were 3.6 × 104 and 270 A W?1, respectively. For P2/PC71BM, P was 2.5 × 104 and R reached 2420 A W?1.
关键词： phototransistors,photoresponsivity,organic field-effect transistors,diketopyrrolopyrrole,NIR polymers,charge transport
更新于2025-09-19 17:15:36
-
Color Sensitive Response of Graphene / Graphene Quantum Dot Phototransistors
摘要： We present the fabrication and characterization of all-carbon phototransistors made of graphene three terminal devices coated with atomically precise graphene quantum dots (GQD). Chemically synthesized GQDs are the light absorbing materials, while the underlying chemical vapor deposition (CVD)-grown graphene layer acts as the charge transporting channel. We investigated three types of GQDs with different sizes and edge structures, having distinct and characteristic optical absorption in the UV-Vis range. The photoresponsivity exceeds 106 A/W for vanishingly small incident power (<10-12 W), comparing well with state of the art sensitized graphene photodetectors. More importantly, the photoresponse is determined by the specific absorption spectrum of each GQD, exhibiting the maximal responsivity at the wavelengths corresponding to the absorption maxima. Overall this behavior can be ascribed to the efficient and selective absorption of light by the GQDs, followed by a charge transfer to graphene, a mechanism known as photogating effect. Our results suggest the use of graphene/GQD devices as valuable photodetectors for application where color sensitivity is required.
关键词： graphene,graphene quantum dots,phototransistors,color sensitivity,photogating effect
更新于2025-09-19 17:13:59
-
Effect of Top Channel Thickness in Near Infrared Organic Phototransistors with Conjugated Polymer Gate-Sensing Layers
摘要： Here, we report the thickness effect of top channel layers (CLs) on the performance of near infrared (NIR)-detecting organic phototransistors (OPTRs) with conjugated polymer gate-sensing layers (GSLs). Poly(3-hexylthiophene) (P3HT) was employed as a top CL, while poly[{2,5-bis-(2-octyldodecyl)-3,6-bis-(thien-2-yl)-pyrrolo[3,4-c]pyrrole-1,4-diyl}-co-{2,2-(2,1,3-benzothiadiazole)-5,5-diyl}] (PODTPPD-BT) was used as a GSL. The thickness of P3HT CLs was varied from 10 to 70 nm. Three different wavelengths of NIR light (λ = 780, 905, and 1000 nm) were introduced and their light intensity was fixed to 0.27 mW cm?2. Results showed that all fabricated devices exhibited typical p-channel transistor behaviors and the highest drain current in the dark was obtained at the P3HT thickness (t) of 50 nm. The NIR illumination test revealed that the NIR photoresponsivity (RC) of GSL-OPTRs could be achieved at t = 50 nm irrespective of the NIR wavelength. The maximum RC of the optimized devices (t = 50 nm) reached ca. 61% at λ = 780 nm and ca. 47% at λ = 1000 nm compared to the theoretical maximum photoresponsivity.
关键词： near infrared,organic phototransistors,channel layers,conjugated polymers
更新于2025-09-16 10:30:52
-
Highly Transparent and Surface-Plasmon-Enhanced Visible-Photodetector Based on Zinc Oxide Thin-Film Transistors with Heterojunction Structure
摘要： Highly transparent zinc oxide (ZnO)-based thin-film transistors (TFTs) with gold nanoparticles (AuNPs) capable of detecting visible light were fabricated through spray pyrolysis on a fluorine-doped tin oxide substrate. The spray-deposited channel layer of ZnO had a thickness of approximately 15 nm, and the thickness exhibited a linear increase with an increasing number of sprays. Furthermore, the ZnO thin-film exhibited a markedly smoother channel layer with a significantly lower surface roughness of 1.84 nm when the substrate was 20 cm from the spray nozzle compared with when it was 10 cm away. Finally, a ZnO and Au-NP heterojunction nanohybrid structure using plasmonic energy detection as an electrical signal, constitutes an ideal combination for a visible-light photodetector. The ZnO-based TFTs convert localized surface plasmon energy into an electrical signal, thereby extending the wide band-gap of materials used for photodetectors to achieve visible-light wavelength detection. The photo-transistors demonstrate an elevated on-current with an increase of the AuNP density in the concentration of 1.26, 12.6, and 126 pM and reach values of 3.75, 5.18, and 9.79 × 10?7 A with applied gate and drain voltages. Moreover, the threshold voltage (Vth) also drifts to negative values as the AuNP density increases.
关键词： gold-nanoparticles,phototransistors,plasmonic energy detection,spray pyrolysis,zinc oxide-based thin-film transistors
更新于2025-09-12 10:27:22