Magnetically Tunable Ag/CH₃NH₃PbBr₃ Single Crystal/Ni Heterostructure for Self-Powered Photodetector

Organometallic halide perovskites have shown immense potential for light harvesting and visible light sensing applications. Large CH 3 NH 3 PbBr 3 single crystals (SC) of size 4 × 3.5 mm 2 have been synthesized using a simple inverse temperature crystallization route. The X-ray diffraction spectra confirm the formation of a single crystalline phase without any impurity. UV–vis diffuse reflectance spectra show an optical band gap of ∼2.28 eV, which is suitable for visible light sensing. Thereafter, the device with architecture Ag/CH 3 NH 3 PbBr 3 SC/Ni was fabricated by thermally depositing the nickel (Ni) and silver (Ag) metal on either side of the SC and was used for visible light sensing applications. The device exhibits a photocurrent of ∼3 μA·cm –2 at a forward biasing of 5 V with responsivity ( R ) ∼14 mA·W –1 and detectivity ( D *) ∼5 × 10 7 Jones. Furthermore, the device is subjected to an external magnetic field (B vector) varying from 0 to 100 mT to analyze the effect of the B vector on device performance. The device shows ∼28% increment in the photocurrent at B vector of 30 mT with significantly higher R and D * of ∼37 mA·W –1 and ∼2 × 10 8 Jones, respectively, which is due to enhanced charge carrier transportation and lower recombination at the Ni/SC interface under the influence of external magnetic field. The present work provides a practicable strategy to tune photocurrent by an external B vector and further pave the way toward multifunctional optoelectronic devices.