Starting materials: Methylamine (CH3NH2), (HI) 57 wt % in water, PbI2
Product: MAPbI3 film
Description: React ~24 mL methylamine (CH3NH2) solution 33 wt% in absolute ethanol with ~10 mL hydroiodic acid (HI) 57 wt % in water with excess methylamine under nitrogen atmosphere in ~100 mL ethanol at room temperature. Crystallize methylammonium iodide (CH3NH3I) using a rotary evaporator to form a white colored powder. Prepare MAPbI3 precursor by dissolving equimolar amounts of methylammonium iodide and PbI2 in DMF at 0.88M in a nitrogen-filled glovebox. Spin-coat film at 2000rpm and anneal at 100 °C for 5 minutes in the glovebox.
Method: Optical absorption
Description: Transmittance and reflectance spectra were collected with a Varian Cary 300 UV-Vis spectrophotometer with an internally coupled integrating sphere.
Starting materials: PbI2, MAI
Product: thin film
Description: The film is produced using a dynamic two-step deposition method. on a compact TiO2/ATO substrate, a N,N-dimethylformamide (DMF) solution of PbI2 is spin coated at 3000 rpm for 10 s, and an isopropyl alcohol solution of methylammonium iodide (MAI) is immediately added dropwise, while keeping the whole spinning time 20 s prior to the end of spin coating. The yellow PbI2 solution turns to brown immediately and gradually darkens during the spin coating. After annealing at 150 °C for 10 min, the as-prepared perovskite film has a shiny black color due to the high visible light absorption and super flat surface. The cross-linking agent 2-aminoterephthalic acid (with different concentrations of 0, 0.2, 0.5, and 1 mg mL−1) was immediately spin-coated on the MAPbI3 film and subsequently annealed at 150 °C for 5 min.
Method: UV-Vis absorption
Description: The absorption spectra were collected by a UV-visible spectrophotometer (UV-3600, Shimadzu Corp.)