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Optimal control problem is typically solved by first finding the value function through Hamilton-Jacobi equation (HJE) and then taking the minimizer of the Hamiltonian to obtain the control. In this work, instead of focusing on the value function, we propose a new formulation for the gradient of the value function (value-gradient) as a decoupled system of partial differential equations in the context of continuous-time deterministic discounted optimal control problem. We develop an efficient iterative scheme for this system of equations in parallel by utilizing the properties that they share the same characteristic curves as the HJE for the value function. For the theoretical part, we prove that this iterative scheme converges linearly in $L_\alpha^2$ sense for some suitable exponent $\alpha$ in a weight function. For the numerical method, we combine characteristic line method with machine learning techniques. Specifically, we generate multiple characteristic curves at each policy iteration from an ensemble of initial states, and compute both the value function and its gradient simultaneously on each curve as the labelled data. Then supervised machine learning is applied to minimize the weighted squared loss for both the value function and its gradients. Experimental results demonstrate that this new method not only significantly increases the accuracy but also improves the efficiency and robustness of the numerical estimates, particularly with less amount of characteristics data or fewer training steps.

By incorporating organic BHJ onto graphene, graphene/ZnO/PTB7-Th:IEICO-4F shows gate tunable photodetection/photostorage switching features for the implementation of both retinomorphic vision and memorial preprocessing functions.

Nonlinear optical activities (e.g., harmonic generations) in two-dimensional (2D) layered materials have attracted much attention due to the great promise in diverse optoelectronic applications such as nonlinear optical modulators, nonreciprocal optical device, and nonlinear optical imaging. Exploration of nonlinear optical response (e.g., frequency conversion) in the infrared, especially the mid-infrared (MIR) region, is highly desirable for ultrafast MIR laser applications ranging from tunable MIR coherent sources, MIR supercontinuum generation, and MIR frequency-comb-based spectroscopy to high harmonic generation. However, nonlinear optical effects in 2D layered materials under MIR pump are rarely reported, mainly due to the lack of suitable 2D layered materials. Van der Waals layered platinum disulfide (PtS2) with a sizable bandgap from the visible to the infrared region is a promising candidate for realizing MIR nonlinear optical devices. In this work, we investigate the nonlinear optical properties including third-and fifth-harmonic generation (THG and FHG) in thin layered PtS2 under infrared pump (1550-2510 nm). Strikingly, the ultrastrong third-order nonlinear susceptibility χ(3)(-3ω;ω,ω,ω) of thin layered PtS2 in the MIR region was estimated to be over 10-18 m2/V2, which is about one order of that in traditional transition metal chalcogenides. Such excellent performance makes air-stable PtS2 a potential candidate for developing next-generation MIR nonlinear photonic devices. Ministry of Education (MOE) National Research Foundation (NRF) Submitted/Accepted version This research was also supported partially by National Research Foundation Singapore program (NRFCRP19- 2017-01 and NRF-CRP22-2019-0007) and Ministry of Education Tier 2 program (MOE-T2EP50120-0009), and Singapore A*STAR funding (A18A7b0058 and A2090b0144).

To overcome the weak absorption deficiency of 2D materials, combining bilayer/bulk heterojunction and 2D materials in a photoconductive framework facilitates the separation and transfer of photo-generated carriers for prominent performance photo-detector. Nevertheless, apart from improving the inferior built-in electric field, the multilayer device may suffer a low efficiency due to depletion loss considering the effective exciton length limitation. Here, we demonstrate the thickness-dependent photocurrent polarity based on a bilayer enhanced graphene/C60/ZnPc phototransistor. A fast response time down to 7.29 μs and a responsivity of 6537 A/W are achieved in the device with the help of type-II band alignment and valid interfaces between organic layers. Moreover, three controlled thicknesses of intermediate charge transfer layer are investigated for the purpose of probing the transfer direction in multilayer heterojunction, which suggests that the photocurrent polarity is highly related to the thickness of C60 and even input optical power density. Owing to the phenomena of photocurrents polarity, a distinct bending curve of responsivity-power density relation is observed near the positive-negative altering point compared to general logarithm linear relation in most photoconductive devices. Our results may enable further exploration of charge transfer mechanism in multilayer system and development of high speed photoconductive transistor.

The significant influence of transverse isotropy on mechanical behaviours of soil has long been recognised, but it is still difficult to capture well under 3D stress conditions. In this study, a method of establishing 3D non-orthogonal elastoplastic (NOEP) constitutive models for transversely isotropic soil (TI-soil) is proposed. The effect of transverse isotropy is considered by extending the characteristic stress with the fabric tensor of TI-soil. The extended characteristic stress can be used to treat the mechanical behaviour of TI-soil from the perspective of isotropic soil. Therefore, a unified strength criterion for TI-soil is developed in the same form as the Drucker–Prager criterion. In order to reflect the non-orthogonality of the plastic flow direction with respect to the yield surface, the non-orthogonal plastic flow rule is adopted, which obviates the tedious work of constructing the plastic potential function or the dilatancy relation. Based on the yield function and hardening parameter expressed in the extended characteristic stress space, specific formulations of the NOEP model for TI-soil can be derived. Comparisons between model predictions and test results show that the developed model can well reflect the effects of transverse isotropy and intermediate principal stress on the strength and deformation behaviour of TI-soil.

The 2D materials Bi2O2Se and graphene have emerged with ultrahigh mobility, showing great potential in near-infrared optical communication and photo-detection with high speed. Nevertheless, for acquiring high photo-responsivity, the prolonged carrier lifetime leads to the photoconductor having an inferior operation speed. In this work, a type-III junction dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN)/Bi2O2Se is constructed on a graphene field-effect transistor, which facilitates photo-generated electron recombination. We observe a broadband response covering the communication band with a highly optimized recovery time down to 101 μs. Consequently, a 3 dB bandwidth of nearly 2 kHz (5-fold improved) is achieved with a 3-fold promotion of detectivity compared to graphene/Bi2O2Se, which is superior in photoconductors. More importantly, with the existence of middle-layer HAT-CN, the external quantum efficiency was improved up to 11.82% with a responsivity to 2420 A W−1. Furthermore, the demonstration of the 3 × 3 array gives potential opportunity in large scale focal imaging. This work not only provides an appropriate path for manufacturing large scale high-performance phototransistors but also exhibits significant potential for high speed optoelectronic applications in the communication band and ultrafast sensing.

Photoelectric detection technology is extremely significant on account of its extensive applications in commercial and military fields, but high-performance array photodetectors based on Dirac semimetal thin film materials are rarely reported. Hence, we demonstrate photodetectors based on a three dimensional (3D) topological Dirac semimetal (DSM) (Cd1−xZnx)3As2/MoO3 array heterojunction, showing ultrahigh photoresponsivity, detectivity and external quantum efficiency in the ultra-broadband spectrum (405–4500 nm) of 3.1 A W−1, 6.4 × 1010 Jones and 855.8%, respectively, meanwhile possessing array unit performance repeatability and excellent time stability under atmospheric conditions at room temperature. The device exhibits an incredible current reversal phenomenon under the action of both light illumination and temperature variation elements, which can be attributed to a thermoelectromotive force effect. These excellent photoelectric properties illustrate that the fabrication of the 3D DSMs/inorganic thin film heterojunction is a suitable method for preparing distinguished infrared array photodetectors in the field of infrared telecommunications and scanning imaging.

Seebeck effect is one of the desirable pathways for developing advanced room-temperature (RT) broadband photothermoelectric (PTE) detectors, which are important for infrared spectroscopy applications. However, achieving high performance PTE detectors utilizing materials with high Seebeck coefficient remains a great challenge and further improvements are highly desired. Herein, we introduce a layered material SnSe with high Seebeck coefficient up to 507 ± 20 μV K−1 and further demonstrate an RT ultra-broadband PTE detector ranging from a visible region to a mid-infrared (MIR) region (0.532–13.2 μm). The detector yields a high responsivity of 0.47 V W−1 and a moderate response speed of 107 ms at an excitation wavelength of 8.1 μm at zero bias, which is comparable or higher than those parameters of the commercial products. Moreover, we have retrieved absorption fingerprints of molecular gases during MIR spectroscopy by using this detector owing to its wide response range, which illustrates great potential of this type of broadband high performance PTE detector toward advanced optoelectronics applications. Agency for Science, Technology and Research (A*STAR) National Research Foundation (NRF) Submitted/Accepted version This research was supported by the National Natural Science Foundation of China (NSFC, Grant Nos. 61922005 and U1930105) and the Beijing Natural Science Foundation (BNSF, Grant No. JQ20027). This research was also supported partially by the National Research Foundation Singapore programme (Nos. NRF-CRP19-2017-01 and NRF-CRP22-2019-0007) and A*STAR Grant Nos. A18A7b0058 and A2090b0144.

Infrared upconversion devices (UCDs) enable low-cost visualization of infrared optical signals without utilizing a readout circuit, which is of great significance for biological recognition and noninvasive dynamic monitoring. However, UCDs suffer from inferior photon to photon (p-p) efficiency and high turn-on voltage (Von ) for upconversion operation, hindering a further expansion in highly resolved infrared imaging. Herein, an efficient organic UCD integrating an interfacial exciplex emitter and a well-designed near-infrared (NIR) detector reveals a high efficiency up to 12.92% and a low Von down to 1.56 V. The low Von gives the capacity for detecting weak NIR light down to 3.2 µW cm-2 , significantly expanding the detection power scale of UCDs. Thus, the imaging linear dynamic range (I-LDR) is highly bias-tunable, ranging from 13.23 to 84.4 dB. The high I-LDR enables highly resolved and strong-penetration bioimaging especially for thick biological sections, indicating great potential in noninvasive defect and pathological detection.

Images obtained from an illuminated scene often have their original colour contaminated. Colour constancy is a study considering how to restore them. Substantial progress on colour constancy has been made in recent years due to the development of a convolutional neural network (CNN). In a CNN structure, high-level features contain semantic information while low-level features show local details. If both are taken into account, they would help achieve a more accurate illuminant estimation. However, previous works paid little attention to the latter for lack of frameworks, which can combine those two kinds of features together. Inspired by the pyramid model, a top-down network that successively propagates high-level information to low-level layers is proposed. This network, named top-down semantic aggregation for colour constancy (TDCC), takes full advantage of the multi-scale representations with strong semantics. As a result, objects with intrinsic colours are captured and a better estimation is obtained. Experiments on three benchmark datasets demonstrate that TDCC significantly outperforms state-of-the-art colour constancy methods.

As a quasi-one-dimensional material, individual single-walled carbon nanotubes are extensively studied due to their anisotropic electronic, thermal and optical properties. However, despite prior efforts to produce large-scale architectures of aligned nanotubes and related devices, macroscopic manifestations of such properties remain limited. In this work, large monodomain films of aligned single-walled carbon nanotubes (SWCNTs) have been prepared by self-assembly. Sodium dodecyl benzene sulfonate and sodium deoxycholate were simultaneously used as surfactant to disperse self-aligned SWCNTs and then carbon nanotubes films got a high degree of alignment with a maximum LDr of approximately 1.6. Furthermore, SWCNTs-Au heterojunctions photodetectors were fabricated and exhibited the enhanced intrinsic polarization-dependent photocurrent as well as anisotropic conductivities. To improve the device responsivity, hydrazine was used as N-doping material and the detector responsivity up to 292.5 mA/W was obtained with a broadband spectral response spanning the visible (405 nm) to the near-infrared (980 nm), which is much higher than former SWCNTs photodetector. This method presents a potential application of spontaneously aligned SWCNTs for efficient, low-cost, scalable Vis-IR detection with a built-in polarimetry.

Polarization-resolved photodetection in a compact footprint is of great interest for ultraminiaturized polarimeters to be used in a wide range of applications. However, probing the states of polarization (SOP) in materials with natural anisotropy are usually weak, limited by the material's natural dichroism or diattenuation. Here, a twisted unipolar-barrier van der Waals heterostructure (vdWH) to construct a bias-switchable polarization detection for retrieval of full SOP (from 0 to 180°) for linear polarized incident light is reported. As a demonstration example, this study realizes the concept in a b-AsP/WS2 /b-AsP vdWH relying on the natural anisotropic properties of the materials without using additional plasmonic/metasurface nanostructures to realize linear polarimetry in the mid-infrared range. Polarimetric imaging is further demonstrated with the developed linear polarimetry by directly displaying the Jones-vector-described SOP distribution of certain target object. This method, with the capabilities of detecting full linear SOP, is promising for the next-generation on-chip miniaturized polarimeters. Agency for Science, Technology and Research (A*STAR) National Research Foundation (NRF) Submitted/Accepted version This research was supported by the National Natural Science Foundation of China (NSFC, Grant Nos. 61922005 and U1930105) and Beijing Natural Science Foundation (BNSF, Grant No. JQ20027). This research was also supported partially by National Research Foundation Singapore programme (NRF-CRP19-2017-01 and NRF-CRP22-2019-0007) and A*STAR Grant Nos. A18A7b0058 and A2090b0144.

2D materials possess superior optoelectronic properties, such as ultrahigh mobility and broadband photoresponse, making them one of the most vital platforms for diversified photodetectors. However, atomic thickness 2D materials usually suffer from intrinsic low absorption. To promote the photodetector performance, a feasible method is to integrate the 2D materials with low-cost, flexible, and tunable organics that form a charge transfer (CT) heterojunction. As results, in-depth multifunctional CT 2D-inorganic/organic detector exhibits extended functions such as low-power consumption, in-memory detection, and optical-bio synapse to meet the demand of contemporary photonic cell. Particularly, the progresses in wafer-scale monocrystal of both 2D and organic materials render vast potential applications with operation frequencies ranging from ultraviolet to terahertz. Here, the recent advances of 2D-inorganic/organic CT photodetectors are comprehensively reviewed by several classifications. Future developments and applications in optical biology, synapsis, and machine vision are also highlighted. Ministry of Education (MOE) National Research Foundation (NRF) Submitted/Accepted version The authors acknowledge financial support from National Science Funds for (Nos. 61922022, 62175026, 62171094 ̧ and 62104026), the Singapore Ministry of Education Academic Research Fund No. MOE-T2EP50120-0009 (S), by the National Research Foundation Singapore programme Nos. NRF-CRP18-2017-02 and NRF-CRP22-2019-0007. Also, thanks for China Scholarship Council.

Graphene has great potential in the field of photoelectric detection due to its excellent photoelectric properties such as wide-band absorption and ultra-high mobility. We combine organic small molecule donor acceptor materials with graphene, and modulate its infrared response by an external light source, which can cause three polar variation of photocurrent states. This polarity modulation feature will play a huge role in future infrared optical logic and modulation devices.

With the rising demand of recording, computing and image capture, advanced optoelectronic detection, storage and logic devices are highly pursued. Nevertheless, multi-functional vision chip based on infrared detection and memory switching has never been demonstrated. Here, by utilizing the electronic extraction layer ZnO and face-on orientation of D-A, we exhibit the broadband visible to near-infrared photo-response and photo-storage characters on graphene phototransistor. Functions as photodetection and photo-storage can be switched with the variation of gate voltage. The device demonstrates high photo-responsivity up to 1.88 × 106 A/W at 895 nm corresponding detectivity of 4.8 × 1012 Jones. Importantly, the rewritable and switching infrared optoelectronic memory function can be achieved with good retention over 104 s. The both retinomorphic vision and memorial preprocessing in artificial visual are simultaneously realized by photodetection/photostorage switching property. Such nearly all-solution processes in our phototransistors may open up the path for the large-scale and easy manufacturing infrared multifunctional bio-optoelectronic device.

With the emergence of bismuth-based oxychalcogenide materials, Bi2O2Se shows superiority in photodetection owing to its favorable mobility and air stability. Nevertheless, the photodetection performance is limited by its low bandgap and extinction coefficient in the near-infrared region. Here, by stacking C60/Bi2O2Se heterojunction onto graphene with a symmetrical electrode, we observed distinctive polarity variation in the broadband photocurrents (488–1550 nm) owing to the wavelength-dependent band alignment. Meanwhile, the all-negative polarity responses of graphene/Bi2O2Se demonstrate high photo-responsivity (∼7160 A W−1) with 1.7 × 106% external quantum efficiency, fast speed down to 57 μs and detectivity up to 6.96 × 1010 Jones, which are superior compared with previous work. A higher photo-responsivity (∼170 A W−1) communication band (1310 and 1550 nm) is realized for graphene/C60/Bi2O2Se than for previous related work. The coupling energy bands of Bi2O2Se and C60 were determined by first-principles calculation, suggesting two carrier transfer paths into the graphene channel (charge separation and tunneling injection). This was further verified by gate modulation and a control group. This unique photo-response phenomenon and high-performance phototransistor will enable next-generation large-scale array optical imaging and provide a valid platform for exploring communication band applications and polarity converting of photocurrents.

We demonstrated an organic upconversion device (UCD) successfully converted input NIR light (850–1310 nm) into 524 nm green emission. The UCD under 980 nm light irradiation exhibits a high photon to photon conversion efficiency of 12%. In addition, the linear dynamic range reaches 72.1 dB and the maximum on/off ratio of luminance reaches 4.4×104, which guarantee the clarity of imaging from 850 to 1310 nm. The UCD in this work has the characteristics of high efficiency and long wavelengths detection, and it makes some senses for long wavelengths NIR bio-imaging in further researches.

The intriguing carrier dynamics in graphene heterojunctions have stimulated great interest in modulating the optoelectronic features to realize high-performance photodetectors. However, for most phototransistors, the photoresponse characteristics are modulated with an electrical gate or a static field. In this paper, we demonstrate a graphene/C60/pentacene vertical phototransistor to tune both the photoresponse time and photocurrent based on light modulation. By exploiting the power-dependent multiple states of the photocurrent, remarkable logical photocurrent switching under infrared light modulation occurs in a thick C60 layer (11 nm) device, which implies competition of the photogenerated carriers between graphene/C60 and C60/pentacene. Meanwhile, we observe a complete positive-negative alternating process under continuous 405 nm irradiation. Furthermore, infrared light modulation of a thin C60 (5 nm) device results in a photoresponsivity improvement from 3425 A/W up to 7673 A/W, and we clearly probe the primary reason for the distinct modulation results between the 5 and 11 nm C60 devices. In addition, the tuneable bandwidth of the infrared response from 10 to 3 × 103 Hz under visible light modulation is explored. Such distinct types of optical modulation phenomena and logical photocurrent inversion characteristics pave the way for future tuneable logical photocurrent switching devices and high-performance phototransistors with vertical graphene heterojunction structures., Phototransistors: a carbon sandwich for logic with light Two forms of carbon and a hydrocarbon are combined in a phototransistor, which creates changes in optical and electronic behavior in response to different wavelengths of light, with properties that will be useful for both research and commercial applications. The innovative phototransistor has been developed by Jiayue Han and colleagues at the University of Electronic Science and Technology of China, in Chengdu, with co-workers at other Chinese research centers. It has a layer composed of spherical C60 molecules, sandwiched between the form of carbon known as graphene and the hydrocarbon pentacene. Gold and silicon-based electrodes complete the structure. The optoelectronic properties created at the junctions between the different layers overcome limitations of simpler graphene based devices. The modulation of optical and electronic behavior achieved by the system could be used in new logical switching devices.

3D Dirac semimetal Cd3As2, as an ideal candidate photosensitive material, has attracted widespread attention due to its excellent characteristics of high carrier mobility and zero band gap. Although photodetector based on Cd3As2 crystal material has been made, there are still huge significances for the utilization of Cd3As2 thin film in commercial devices. In this paper, we demonstrated a wide-band photodetector based on heterojunction of Cd3As2 thin film and pentacene for the first time. This photodetector can detect the radiation wavelength from 450 nm (visible region) to 10600 nm (long wave infrared region) at room temperature, exhibiting high current responsivity (36.15 mA/W) and external quantum efficiency (7.29%) at 650 nm, of which Ri is more than six times as high as previously reported that of crystalline Cd3As2 devices. Most interestingly, the far-infrared current responsivity of this detector at 10600 nm can reach 1.55 mA/W, which is extremely difficult for other 2D material detectors. Overall,...

High responsivity, fast response time, ultra-wide detection spectrum are pursuing goals for state-of-art photodetectors. Cd

Three-dimensional (3D) convolutional neural network (CNN) is widely used for action recognition. However, it performs same on time and space, which dose not match asymmetry of time. To overcome this problem, we propose the time-asymmetric 3D CNN based on the hypothesis that the early frames persist. Our time-asymmetric 3D CNN performs better on Kinetics-400 than normal 3D CNN with less parameters. And it can get comparable results on UCF101 among leading methods, which indicates that our time-asymmetric 3D CNN is a good choice for action recognition.

Color constancy considers the problem of restoring the original color of an illuminated scene. Benefiting from the development of Convolutional Neural Network (CNN), substantial progress on color constancy has been made. High-level features of CNN structure contain semantic information while low-level features show local details. If both are taken into account, they would help achieve a more accurate illuminant estimation. However, previous works paid little attention to the latter for there lacks frameworks which can combine those two kinds of features together. Inspired by the pyramid model, a top-down network that successively propagates high-level information to low-level layers is proposed. This network, named Top-down Semantic Aggregation for Color Constancy (TDCC), takes full advantage of the multi-scale representations with strong semantics. As a result, objects with intrinsic colors are captured and a better estimation is obtained. Experiments on three benchmark datasets demonstrate that TDCC significantly outperforms state-of-the-art color constancy methods.

Nitrogen analogues of Chichibabin's and Muller's hydrocarbons, DPh-D and TPh-D, based on 1,2,4-benzotriazinyl (Blatter) were studied. The two diradicaloids with good chemical and thermal stability exhibit smaller singlet-triplet energy gaps (ΔES-T from -1.05 to -1.27 kcal mol-1) than the hydrocarbon diradicaloids with the same bridges.

Terahertz focal plane array imaging technology can realize real-time terahertz imaging with high frame rate. But for a relatively large-sized object imaging, the array scanning should collect a plurality of original image data due to the small-sized focal plane terahertz detector array. In this paper we demonstrate terahertz image preprocessing, image register and image blending in detail. In order to reduce the image noise and enhance the image contrast, we manifest a novel method to preprocess the image by incorporating of Butterworth band-elimination filter and high-frequency nonlinear enhancement methods. Meanwhile, the enhanced image is stitched using the sift algorithm. The experimental result present that the proposed method can accurately mosaic the terahertz grayscale image, which is beneficial to realize the scanning and stitching imaging of large-area objects by focal plane array terahertz detector.

Recently, heterojunction photodetectors have attracted significant interest due to the multiple degrees of freedom reorganization, integrating advantages of different typed materials. Herein, a high‐performance photodetector based on a 3D Dirac semimetal Cd3As2/tungsten disulfide (WS2) heterojunction is demonstrated, which is constructed by directly transferring exfoliated 2D few layer WS2 on Cd3As2 nano‐belt and following by annealing treatment. The resulting Cd3As2/WS2 heterojunction device presents superior performance with a high on/off ratio (≈5.3 × 104) and a responsivity (Ri) of about 223.5 AW−1 at 520 nm, as well as an outstanding detectivity (D*) of about 2.05 × 1014 Jones at 808 nm near‐IR waveband. However, the optimized noise equivalent power (NEP) is evaluated about 6.17 × 10−14 WHz−1/2 by the noise power density spectrum. The excellent performance can be attributed to a high‐quality heterostructure interface, strong light absorption capacity, and ultralow dark current in a Cd3As2/WS2 heterojunction system. This work provides a promising platform to develop a high‐performance optoelectronic device based on 3D Dirac semimetal and 2D TMDs families.

Recently, discovery of three-dimensional (3D) topological Dirac/Weyl semi-metal opens up a new frontier fields for neoteric type of photodetectors. As a most representative 3D Dirac semi-metal, Cadmium arsenide (Cd3As2) has ultra-high charge mobility beyond graphene and possess strong light and matter interaction. Herein, photodetector prototype based on micro-nanometer scaled Cd3As2 was developed, which has high photocurrent response even under slight bias of 1 mV and its responsivity could be up to 4.65 A/W at near infrared waveband of 808 nm. Moreover, the Cd3As2/CuPc heterojunction was further introduced for suppress dark current of Dirac semimetal Cd3A2 nanobelt that would effectively improve photoelectric detection performance. As expected, the responsivity (R) of Cd3As2/CuPc has been significantly enhanced in visible (405 nm) to near-infrared (980 nm) region, and maximum R and optimal detectivity (D*) of detector can be reach about 142.5 A/W and 7.83 × 1010 Jones under irradiation of 808 nm laser, respectively. All of the results indicate that 3D Dirac semi-metal Cd3As2 and its heterojunction design are great prospect applied in high-performance broadband detection devices.

High responsivity, fast response time, ultra-wide detection spectrum are pursuing goals for state-of-art photodetectors. Cd3As2, as a three-dimensional (3D) Dirac semimetal, has a zero bandgap, high light absorption rate in broad spectral region, and higher mobility than graphene at room temperature. However, photoconductive detectors based Cd3As2 suffer low quantum efficiency due to the absence of high built-in field. Here, a Cd3As2 nanoplate/multilayer MoS2 heterojunction photodetector was fabricated which achieved a quite high responsivity of 2.7 × 103 A W-1 at room temperature. The photodetector exhibits a short response time of in broad spectra region from ultraviolet (365 nm) to short-wavelength-infrared (1550 nm) and reached 65 μs at 650 nm. This work provides a great potential solution for high-performance photodetector and broadband imaging by combining 3D Dirac semi-metal materials with semiconductor materials.