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, a novel environment-friendly antisolvent tert-amyl alcohol (TAA) is employed first 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, thus leading to the formation of high-quality perovskite films and enhanced photodetector performance. As a result, the responsivity of the PPD reaches 1.56 A/W under the illumination of 532 nm laser with the power density of 6.37μW/cm2 at a bias voltage of -2V, which is good responsivity for PPDs with the vertical structure and only CH3NH3PbI3 perovskite as the photosensitive material. The corresponding detectivity reaches 1.47×1012 Jones, while the linear dynamic range reaches 110 dB. These results demonstrate that our developed green antisolvent TAA has remarkable advantages for the fabrication of high-performance PPDs and can provide a reference for similar research work.

Chiral metasurfaces based on asymmetric meta-atoms have achieved artificial circular dichroism (CD), spin-dependent wavefront control, near-field imaging, and other spin-related electromagnetic control. In this paper, we propose and experimentally verify a scheme for achieving high-efficiency chiral response similar to CD of terahertz (THz) wave via phase manipulation. By introducing the geometric phase and dynamic phase in an all-silicon metasurface, the spin-decoupled terahertz transmission is obtained. The giant circular dichroism-like effect in the transmission spectrum is observed by using a random phase distribution for one of the circular polarization components. More importantly, the effect can be adjusted when we change the area of the metasurface illuminated by an incident terahertz beam. In addition, we also demonstrate the spin-dependent arbitrary wavefront control of the transmitted terahertz wave, in which one of the circularly polarized components is scattered, while the other forms a focused vortex beam. Simulated and experimental results show that this method provides a new idea for spin selective control of THz waves.

Self-powered and flexible ultrabroadband photodetectors (PDs) are desirable in a wide range of applications. The current PDs based on the photothermoelectric (PTE) effect have realized broadband photodetection. However, most of them express low photoresponse and lack of flexibility. In this work, high-performance, self-powered, and flexible PTE PDs based on laser-scribed reduced graphene oxide (LSG)/CsPbBr3 are developed. The comparison experiment with LSG PD and fundamental electric properties show that the LSG/CsPbBr3 device exhibits enhanced ultrabroadband photodetection performance covering ultraviolet to terahertz range with high photoresponsivity of 100 mA/W for 405 nm and 10 mA/W for 118 μm at zero bias voltage, respectively. A response time of 18 ms and flexible experiment are also acquired at room temperature. Moreover, the PTE effect is fully discussed in the LSG/CsPbBr3 device. This work demonstrates that LSG/CsPbBr3 is a promising candidate for the construction of high-performance, flexible, and self-powered ultrabroadband PDs at room temperature.

Highly sensitive broadband photodetection is of critical importance for many applications. However, it is a great challenge to realize broadband photodetection by using a single device. Here we report photodetectors (PDs) based on three-dimensional (3D) graphene foam (GF) photodiodes with asymmetric electrodes, which show an ultra-broadband photoresponse from ultraviolet to microwave for wavelengths ranging from 102 to 106nm. Moreover, the devices exhibit a high photoresponsivity of 103A·W?1, short response time of 43 ms, and 3 dB bandwidth of 80 Hz. The high performance of the devices can be attributed to the photothermoelectric (PTE, also known as the Seebeck) effect in 3D GF photodiodes. The excellent optical, thermal, and electrical properties of 3D GFs offer a superior basis for the fabrication of PTE-based PDs. This work paves the way to realize ultra-broadband and high-sensitivity PDs operated at room temperature.