Photoelectric response characteristics of a novel translucent one-dimensional MAPbI<sub>3</sub>·DMF single crystal material

Abstract

<p indent=0mm>Organic halide perovskites have broad application prospects in photoelectric detector due to their excellent photoelectric properties. Moreover, there has been growing interest in applying halide perovskites to semitransparent photovoltaics to achieve the highest combination of transparency and efficiency. In this paper, we aimed to prepare high-performance materials which are suitable for translucent optoelectronic devices using new preparation methods and explore the potential properties of these materials. We successfully synthesize a type of translucent linear MAPbI₃·DMF single crystal material with controllable size and good stability in atmospheric environment using the anti-solvent method. Toluene, which is often used as one of the surfactants to control the morphology of the perovskite films, was used as an anti-solvent in this paper. The growth of the one-dimensional (1D) single crystal wires was regulated by the control of the adsorbed toluene molecular at the interface, promoting the [PbI₆]⁴⁻octahedral unit in the precursor to assemble into a chain structure along the 1D direction. In addition, we could control the width and length of the single crystal wires via a slow cooling process. The width can reach tens of microns, and the length of the single crystal wires can be the centimeter level. The crystal structure of the transparent wire was analyzed using single crystal X-ray diffraction (XRD). The material exhibited a good 1D chain structure with an infinitely extended single edge-sharing octahedral lead halide chain {PbI₃}⁻ surrounded by CH₃NH₃⁺ (MA) and <italic>N</italic>,<italic>N</italic>-dimethylformamide (DMF). Through XRD characterization of the crystal structure after keeping the material at room temperature in air (~25°C, humidity ~40%) for a long time, we found that the single-crystal wire showed good stability in air. In addition, <italic>in situ </italic>heating XRD and <italic>in situ</italic> heating transmission electron microscopy (TEM) analyses showed that the morphology and crystal structure of the semi-transparent perovskite remained stable at 90°C, indicating that this material has good thermal stability. Further, an ultraviolet-visible absorption spectroscopy test showed that this material could absorb photons at <sc>300–800 nm,</sc> indicating that the obtained single crystal wire could absorb both ultraviolet and visible light. The material also exhibited a strong transmission effect for photons with wavelengths ranging from 500 to <sc>784 nm,</sc> indicating that the material has the semi-transparent property. According to the absorption spectrum, the transparency was calculated, and it was found that the transparency of single crystal materials increased in the range of more than <sc>500 nm,</sc> further implying that they have excellent translucence properties. Photoluminescence (PL) spectrum test showed that the single crystal material could emit <sc>~780 nm</sc> of fluorescence under laser irradiations of 409 and <sc>633 nm.</sc> Furthermore, using the Tauc plot method, we determined that this material has a bandgap of <sc>~1.58 eV,</sc> which is consistent with the PL test. In addition, this material shows good responsivity <sc>(7.13 A W^–1)</sc> with a response time of <sc>9.95 ms,</sc> making it suitable for photodetector applications. The good stability and photoelectric properties make this linear single crystal material an ideal candidate for the core absorbent layer of semi-transparent photodetector devices. This research work is expected to provide a reference for the development of transparent perovskite materials with high stability and good photoelectric properties.