Magnetically Tunable\nAg/CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> Single Crystal/Ni\nHeterostructure for Self-Powered\nPhotodetector

Organometallic halide perovskites have shown immense\npotential\nfor light harvesting and visible light sensing applications. Large\nCH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> single crystals (SC)\nof size 4 × 3.5 mm<sup>2</sup> have been synthesized using a\nsimple inverse temperature crystallization route. The X-ray diffraction\nspectra confirm the formation of a single crystalline phase without\nany impurity. UV–vis diffuse reflectance spectra show an optical\nband gap of ∼2.28 eV, which is suitable for visible light sensing.\nThereafter, the device with architecture Ag/CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> SC/Ni was fabricated by thermally depositing the\nnickel (Ni) and silver (Ag) metal on either side of the SC and was\nused for visible light sensing applications. The device exhibits a\nphotocurrent of ∼3 μA·cm<sup>–2</sup> at\na forward biasing of 5 V with responsivity (<i>R</i>) ∼14\nmA·W<sup>–1</sup> and detectivity (<i>D</i>*)\n∼5 × 10<sup>7</sup> Jones. Furthermore, the device is\nsubjected to an external magnetic field (B vector) varying from 0\nto 100 mT to analyze the effect of the B vector on device performance.\nThe device shows ∼28% increment in the photocurrent at B vector\nof 30 mT with significantly higher <i>R</i> and <i>D</i>* of ∼37 mA·W<sup>–1</sup> and ∼2\n× 10<sup>8</sup> Jones, respectively, which is due to enhanced\ncharge carrier transportation and lower recombination at the Ni/SC\ninterface under the influence of external magnetic field. The present\nwork provides a practicable strategy to tune photocurrent by an external\nB vector and further pave the way toward multifunctional optoelectronic\ndevices.