Perovskite structures of organic and inorganic halides are peculiar structures with many interesting properties. Using their photoelectric effect, the structures have been used in photocells, photoelectric sensors, and light-emitting diodes. In conventional perovskite film crystallization, which is a one-step method, the MAPbI 3 crystals form disordered needlelike crystals at room temperature. Such needlelike crystal films have rough surfaces and low coverage to the substrate, resulting in insignificant photoelectric effects. With the assistance of an electric field and three-dimensional (3D) printing, the direction of the perovskite needlelike crystal can be arranged to make it orderly. In this way, the photoelectric sensor of the ordered MAPbI 3 perovskite needlelike crystal film can be prepared. This sensor has high sensitivity, high stability, and high response speed. Moreover, it has anisotropy and higher photoelectric sensitivity in the direction perpendicular to the needle crystal. Most interestingly, the sensors respond differently to polarized light in different directions, and this effect can be used to detect the direction and degree of polarization of polarized light.

The crystallization of the perovskite structure of organic and inorganic halide depends on its composition and environmental condition. The most convenient method for the preparation of MAPbI3 perovskite films is the one-step method on TiO2 substrate, which will produce disordered needle-like MAPbI3 perovskite films with poor surface morphology. The electric polarity of MAPbI3 perovskite needle-like crystals was used to arrange the MAPbI3 perovskite needle-like crystals and prepare orderly MAPbI3 perovskite needle-like crystal films to improve their surface morphology. A microdrop-on-demand jetting 3D printing system that can simply add physical fields such as electric field was used to print perovskite narrow line films, which helps to improve the anisotropy of perovskite films. At room temperature and under electric field, ordered needle-like MAPbI3 perovskite crystal film can be obtained to improve the morphology and performance of perovskite film. This phenomenon is helpful for us to explore the influence and application of electrical polarity in the preparation of perovskite needle-like crystal films