Three-dimensional (3D) perovskite photodetectors (PPDs) demonstrate remarkable photoelectric detection ability, but the intrinsic instability of 3D perovskite films against moisture, oxygen, and temperature has been a roadblock for achieving great stability and reliability of the resulting PDs, which can be mainly ascribed to the inevitable defects on surfaces and grain boundaries that can incur nonradiative charge recombination to impair device performance and initiate the degradation of perovskites. In this work, we introduced the two-dimensional (2D) perovskite material PEAI to fabricate a high-performance and stable 2D/3D stacked PPD. As a result, the responsivity of the PEAI processed PPD (PEAI-PPD) reached 1.19 A/W under the illumination of 532 nm laser with the power density of 5 µW/cm2 at bias voltage of -1 V, and retains 80.15% of the initial value after 16 days of nonencapsulated storage at 10%-15% relative humidity (RH). Our work provides a simple and effective method for the fabrication of high-performance and stable 2D/3D stacked PPDs, which has great application potential in visible light communication, imaging and environmental monitoring under complex environmental conditions. © 2022 SPIE

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. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

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. © 2020 SPIE.

Infrared photodetectors (IRPDs) are of importance devices with wide applications from face identification to space communication. With the investigation of thermoelectric materials, perovskite and three-dimensional (3D) graphene have been demonstrated and fabricated to thermoelectric PDs with response to terahertz bands separately. Herein, we develop thermoelectric PD based on 3D graphene and perovskite hybrid material with good IR performance. The responsivity at 1 V bias reaches to 0.1 A/W, under the illumination of 1064 nm laser with the power density of 3.1 mW, corresponding noise equivalent power (NEP) 1 nW Hz-1/2, the rise time 10.8 ms and fall time 12.8 ms, respectively. These results demonstrate these hybrid IRPDs show good IR performance, and can provide a reference for other spectral range such as terahertz bands. © 2020 SPIE.

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. © 2020 SPIE.

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. © 2020 SPIE.