Effect of antisolvent dripping time on the photodetection performance of silicon/MAPbI3 heterojunction

In this work, we developed a silicon/CH₃NH₃PbI₃ (MAPbI₃) heterojunction-based photodetector under ambient conditions using the antisolvent treatment method. To achieve the best morphology and coverage in the perovskite thin film, we investigated the antisolvent dripping time by tracking the turbid point during the spin coating of the perovskite precursor solution on the substrate. By introducing the antisolvent in the processing window just before reaching the turbid point, we successfully obtained a dense MAPbI₃ film with improved surface coverage, exhibiting elevated absorption within the wavelength range of 300–550 nm. The performance of silicon/MAPbI₃ heterojunction-based photodetectors is also influenced by the antisolvent dripping times relative to the turbid point. The dark current of the champion device is suppressed by about ten orders of magnitude when the antisolvent treatment is applied a second before the turbid point. The optimal device demonstrates a responsivity of 30 mA/W and a specific detectivity exceeding 10 ¹ ⁰ Jones at -9V under 25 mW/cm² light illumination at 530 nm.