Publisher’s Note: This paper, originally published on 27 February 2019, was replaced with a corrected/revised version on 16 November 2021. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.
Publisher’s Note: This paper, originally published on 27 February 2019, was replaced with a corrected/revised version on 28 December 2020. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.
Organic-inorganic metal halide perovskite material is an emerging semiconductor material that is widely used in functional devices such as solar cells and photodetectors. It has many advantages, low preparation cost, high light absorption coefficient, long carrier diffusion length, high carrier mobility, etc. However, due to the instability of perovskite, it is easy to decompose in the water and oxygen environment, which has become an obstacle to its development. In this paper, by adding polymethyl methacrylate to the anti-solvent to reduce the perovskite grain boundaries, improve directional growth and the quality of the film. The performance of the photodetector prepared by this method has been effectively improved, there is a significant photocurrent under illumination, and the stability has also been improved. This method provides a good candidate for the next generation of high-performance photodetectors.
Organic field-effect transistor (OFET) photonic memories have attracted significant attention due to their special memory mechanism and potential application, such as image capture and light information storage. Conventional OFET memories based on SiO2 blocking dielectric layer usually need a high programming and erasing voltage, which is not conducive to the needs for future market applications. Here, the low-voltage OFET photonic memory is investigated by using spin-coated organic polymer as the blocking dielectric layer and blending film of CsPbBr3 quantum dots (QDs) and polystyrene (PS) as the charge trapping layer, respectively. The thin poly(methyl methacrylate) (PMMA) film is used as the first blocking dielectric layer, and the ultrathin polyvinyl alcohol (PVA) film is used as secondary blocking dielectric layer on the top of PMMA. Due to the use of thin polymer blocking dielectric layers, the operating voltages of the photonic memory can be as low as 5 V. And the photo-generated carriers can be effectively trapped and released in photosensitive charge trapping layer during the photo-programming and electrical erasing operations. In addition, the memory characteristics of the photonic memory are comparable to that of traditional memories with SiO2 blocking dielectric layer. Multi-level data storage can be obtained in the memory by applying different photo-programming conditions. The low-voltage OFET memory device also presents well retention and endurance. Hence, the low-voltage OFET photonic memory using solution-processed polymer blocking dielectric and photosensitive charge trapping layer shows great potential for the application in optoelectronic devices in terms of large-area and low cost.
The preparation of high-quality perovskite films with optimal morphologies is important for achieving high-performance perovskite photodetectors (PPDs). An effective strategy to optimize the morphologies is to add antisolvents during the spin-coating steps. In this work, an environment-friendly antisolvent ethyl acetate (EA) was employed to improve the quality of perovskite films, which can effectively regulate the formation of an intermediate phase staged in between a liquid precursor phase and a solid perovskite phase due to its moderate polarity, and further promote the homogeneous nucleation and crystal growth in the subsequent annealing process, thus leading to the formation of high-quality perovskite films and enhanced photodetector (PD) performance. As a result, the responsivity of the PPDs reached 0.85 A W-1 under the illumination of 532 nm laser with the power density of 6.37 μW cm-2 at bias voltage of -2 V. The corresponding detectivity reached 3.27 × 1011 Jones, while the rise time and fall time are 256 ns and 370 ns, respectively. These results demonstrates that our developed solution-processed method with EA as antisolvent has remarkably advantages for the fabrication of high-performance PPDs and can provide a reference for the other similar research work.
Terahertz (THz) waves are electromagnetic waves with frequencies between 0.1 THz and 10THz. With the rapid development of wireless communication, the existing spectrum resources have become increasingly scarce. Developing the new frequency band of wireless communication has gradually become a consensus to solve this contradiction. There are a lot of unexploited resources in THz frequency range, making terahertz play a decisive role in the future development of wireless communication. Three-dimensional (3D) graphene with connection carbon nanomaterials is expected to possess better optical and electrical properties than single-layer graphene. In this paper, we studied a room temperature ultra-broadband photodetector based on 3D graphene and investigated the different photoresponse at 0.22, 2.52, 30 THz. Obvious photocurrents and ultra-broadband absorption from infrared spectrum to terahertz (THz) region can be measure in the three 3D graphene. A high photoresponsivity of 15.3 mA W-1 and a fast time response of 20 ms have been achieved at 2.52 THz. The results reveal 3D graphene a good candidate for room-temperature broadband Terahertz detector.
Quantum dots have widely used in a lot of micro-nano photoelectric devices. In this work, PbS quantum dots have been synthesized successfully then a RRAM based on those quantum dots and PMMA mixture material was prepared by solution processed method at room temperature. We have demonstrated that the memory device shows typical resistance switching characteristic and high resistance ratio ( >104). To study the quantum dots based RRAM provides an opportunity to develop the next generation high-performance memory devices and open up a new application field of QDs materials in the future.
Graphene is a hot material for photodetectors due to its high carrier mobility, superior electronic and optical properties. However, the low optical absorption (2.3%) of graphene results in a low photoresponsivity, which limits its wide application in photodetection field. Three-dimensional (3D) graphene with connection carbon nanomaterials is expected to possess better optical and electrical properties than single-layer graphene. In this paper, we studied an ultra-broadband photodetector based on 3D graphene and investigated the different photoresponse with three kinds of 3D graphene including the 3D reduced oxide graphene foam (rGOF), the 3D Nickel (Ni) skeleton graphene foam (GF) and the 3D removal of nickel graphene foam (RNi GF). Obvious photocurrents and ultra-broadband absorption from ultraviolet (UV) spectrum to terahertz (THz) region can be measure in the three 3D GF. A high photoresponsivity of 50 mA W-1 and a fast time response of 100 ms have been achieved. Particularly, the 3D RNi GF presents the highest absorption coefficient of 200 cm-1 at THz region. The results reveal 3D graphene a good candidate for broadband photodetectors.
CsPbIxBr1-x thin film with spontaneous polarization can be made into the self-powered photodetector based on light induced pyroelectric effect. It can perform without an external power source to meet the demands of the portable and wearable nanodevices. Here, a novel self-powered photodetector based on all-inorganic halide perovskites CsPbIxBr1-x thin film is fabricated, which shows an ultrafast response speed of less than 6μs under the laser illumination at zero bias. Also, the response characteristics of the self-powered photodetector from UV to near infrared are experimented and exhibited. Especially, the device has a higher response to 405nm UV light than other. This work extends the potential applications of perovskites in energy scavenging and self-powered sensor systems.
Based on the loss of laser-induced acoustic signal caused by the undulation of sea level, which affects the communication quality of laser-induced underwater communication system, a laser-induced underwater communication zoom optical system with a focusing position of 10km and a focusing position variation range of ±500m is designed. The theoretical relationship between the adjustment distance and the focusing position is established and the far-field distribution of the Gaussian beam focusing system is simulated. The results show that the energy density of the far-field spot is concentrated, and the spot energy is the highest at the focusing position. The sea level condition was simulated, and the indoor pool experiment was carried out to verify the communication performance of the laser-induced acoustic communication system. The experimental results show that the waveform of the laser-induced acoustic signal and the rising edge of the electrical signal are completely consistent, there is no loss of the laser-induced acoustic signal, and the underwater communication quality is good. It provides a viable reference for laser-induced underwater communication systems with adaptive zoom.
All-inorganic perovskite quantum dots (QDs) have widely used in a lot of micro-nano photoelectric devices. However, resistive random access memory (RRAM) devices based on All-inorganic perovskite QDs are relatively scarce. In this work, a RRAM, which exhibits the write-once-read-many-times (WORM) memory effect, based on CsPbBr3 QDs was successfully fabricated by solution processed method at room temperature. The CsPbBr3 QDs based memory shows great reproducibility, good data retention ability, irreversible electrical transition from the high resistance state (HRS) or OFF state to the low resistance state (LRS) or ON state and the resistance ratio (ON/OFF) can reach almost 107. To study the CsPbBr3 QDs based WORM memory provides an opportunity to develop the next generation high-performance and stable WORM devices.
Graphene is a new type of two-dimensional (2D) nanomaterial composed of single-layer carbon atoms. It has high carrier mobility, good optical performance, good mechanical performance and thermal conductivity. Three-dimensional (3D) reduce graphene oxide (rGO) foam integrates the structure of 2D graphene with three-dimensional network connected structure of carbon nanomaterials, which is in a seamless connection possessing better optical and electrical properties. 3D GF has achieved some results in solar cells and supercapacitors, however, field effect transistors are rarely studied. In this paper, a kind of field effect transistor (FET) based on 3D rGO foam has been fabricated and its photoelectric response characteristics have been studied. The results show that an obvious photocurrent could be measured when the laser irradiate on the 3D rGO foams channel. The magnitude of the photocurrent can be effectively modulated by the back-gate voltage. The device exhibits a “V” shape transfer curves and stabile and reproducible photocurrent cycles. Particularly, a high photoresponsivity of 7.8 mA W-1 is achieved, which reveals 3D rGO foams a good candidate for photodetectors.
Methylammonium lead halide perovskites have received substantial attention in photoelectric research communities, because of excellent optoelectronic properties, including long electron-hole diffusion distance, large absorption coefficients in the UV–Vis spectral region, low-cost, solution-based processing and low binding energy of exciton. Many records, such as efficiencies have been kept by these perovskite solar cells. However, other excellent properties, such as ultrafast properties have not been studies intensively. Here vertical field effect phototransistors (VFEpTs) based on methylammonium lead halide perovskites were design and fabricated. VFEpTs exhibit high performances including an ultrafast photoresponse time (less than 20 ns) and a high photoresponsivity (~ 10 mAW−1). The methylammonium lead halide perovskite vertical phototransistors open path on ultrafast devices with low cost solution fabrication process, but high level performances.
All-inorganic cesium lead halide perovskite quantum dots (PQDs) have been applied in optoelectronic fields owing to their unique properties including high carrier mobility, air stabilities and highly efficient photoluminescence. To overcome existing limitations in photodetection for light with particular wavelength and cost of state-of-the-art systems, new-style device structures and composite material systems are needed with low-cost fabrication and high performances. Here we synthesized the CsPbX3 (X = Cl, Br, and I) PQDs by changing the composition at room temperature and fabricated vertical field effect phototransistors (VFEpTs) with Au/Ag nanowires as the transparent source electrode and composition-dependent CsPbX3 (X = Cl, Br, and I) PQDs as active materials. It dominates to obtain photoresponse for specific wavelength in the visible spectrum and high performances. Particularly, VFEpTs based on CsPbCl1.5Br1.5 CsPbBr3, and CsPbBr1.5I1.5 PQDs are sensitive for blue, green, and red lights, respectively. It is worth mentioning that the device exhibits quantitative characterization for the contents of white light. Furthermore, CsPbX3 VFEpTs exhibit high performances including a short photoresponse time (less than 6 ms) and a high photoresponsivity (<9 × 104 AW−1). Allinorganic PQDs open up opportunities to integrate inorganic semiconductors, into high performances and flexible devices by using low cost, room temperature, large area, and solution based methods.
To overcome existing limitations in sensitivity and cost of state-of-the-art systems, new-style device structures and composite material systems are needed with low-cost fabrication and high performance. Vertical field effect photodetectors are fabricated with Au/Ag nanowires as the transparent source electrode and with vertically stacked layers of CsPbBr3 and lead sulfide quantum dots, which formed heterojunctions. The built-in electric field in the layered heterojunction aids the separation of photoinduced excitons, while the short channel enables efficient carrier transport across the active region. Both of these benefits enable a high photo performance and fast photoresponse. This vertical phototransistors exhibit a wide response spectrum from 400 to 2100 nm, a high photoresponsivity of more than 9 × 108 AW−1, and a high detectivity of up to 2 × 1017 Jones (cm Hz1/2 W−1) under infrared illumination. Additionally, this vertical phototransistor had a response time of 3 μs. The solution –based fabrication process and excellent device performances strongly underscore vertical architecture combined with the layered heterojunction as a promising approach for future photodetection field.
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