Starting materials: SnI2, HI, C4H9NH2
Product: Dark red sheetlike crystals
Description: Grow the crystals under slowly-cooled aqueous hydriodic acid solutions. Perform all synthetic steps and crystal manipulations after synthesis in an inert atmosphere to prevent oxidation. Dissolve 0.481 g (1.29 mmol) of SnI2 in 2 mL of concentrated (57 wt %) aqueous HI solvent under flowing argon at 90 °C. In a separate tube, dissolve 2.58 mmol of (C4H9NH2).HI in 3 mL of concentrated HI solution and add to the metal halide solution. Ramp the solution temperature at 2 °C/h from 90 to -10 °C, filter the crystals formed under argon or nitrogen and dry in argon at 80 °C.
Method: Photoluminescence
Description: Collect the photoluminescence spectra within several hours after the crystals were synthesized, and maintain the samples in an argon-filled cell during measurement to prevent degradation. The photoluminescence spectra were excited by 457.9 nm (2.71 eV) light from an argon ion laser. This light was strongly absorbed by each sample, ensuring that the observed luminescence came from the front side of the samples. The excitation density was below 1 W cm-2. Refer to Page 794 for details.
Starting materials: BAI, SnI2, HI, H3PO2
Product: Single crystals of 2D tin halide perovskites. Thin flakes were then exfoliated from the single crystals.
Description: Single crystals synthesized by slow cooling method. Growth solution prepared with 0.45mmol BAI, 0.40mmol SnI2, 1mL HI, and 0.1mL H3PO2 in a sealed glass vial and placed in a muffle furnace and heated until completely dissolved. Solution cooled to room temperature at a rate of 2°C/hour. Crystals were then dried and stored in a nitrogen glove box.
Method: Photoluminescence spectroscopy
Description: Samples excited with mercury fluorescence light source (C-LHGFI HG LAMP). The flourescence filter cube contains a bandpass filter from 330-385 nm for excitation, a dichroic mirror with a cutoff wavelength of 400nm for light splitting, and a long pass filter of 410nm for emission. PL spectra were collected by Princeton Instruments spectrometer (HRS-300S).