ABSTRACT
Metal halide perovskites are studied for photodetection applications because of their outstanding optical and electrical properties. A self-powered ultraviolet-to-near infrared broadband photodetector based on a Ag-doped CsPbI3/PEDOT:PSS heterojunction was investigated. The photodetector using a CsPbI3:Ag/PEDOT:PSS heterostructure with a planar photoconductive structure operated over a broad 355-1560â nm wavelength range in self-powered mode. A terahertz signal was modulated with the CsPbI3:Ag/PEDOT:PSS structure at low optical excitation intensity to investigate its photodetection mechanism. The experimentally designed detector can present images of the letters "C", "N" and "U" in the visible and near-infrared wavelengths, indicating a potential broadband imaging application.
ABSTRACT
The organic-inorganic hybrid perovskite CH3NH3PbBr3(MAPbBr3) has been well developed in the X-ray to visible light band due to its superior optoelectronic properties, but this material is rarely studied in the infrared band. In this paper, a UV-NIR broadband optical detector based on MAPbBr3 single crystal is studied, and the response range can reach the near-infrared region. In the visible light band, the optical response of the device is mainly caused by the photoelectric effect; in the near-infrared band, the optical response of the device is mainly caused by the thermal effect. The carrier response of MAPbBr3 material under different wavelengths of light was investigated using a non-contact measurement method (optical pump terahertz (THz) probe spectroscopy). This paper also builds a set of photoelectric sensor array components, and successfully realizes the conversion of optical image signals to electrical image signals in the visible light band and infrared band. The experimental results show that MAPbBr3 crystals provide a new possibility for UV-NIR broadband photodetectors.
ABSTRACT
Morphology engineering was investigated for hybrid perovskites CH3NH3PbI3:Ag/Poly(3, 4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) that were fabricated in both air and nitrogen environments for active terahertz (THz) memory modulation. Under low optical excitation or an applied bias, THz amplitude modulation or rapid restore in both CH3NH3PbI3:Ag/PEDOT:PSS hybrid structures were demonstrated. The recovery time of the modulated THz wave in the sample fabricated in air was considerably longer than that of the sample fabricated in nitrogen because of defect states induced by a high degree of roughness. THz transmissions were used as coded pixel units and were programmed to store a 4×4 image or a multi-order signal. Hence, active THz memory modulation was demonstrated. It also has potential applications as a visible to near-infrared broad-spectrum light detector.
