Starting materials: (PEA)2PbI4 crystals, DMF, glass substrates
Product: Thin film on glass
Description: Dissolve the 2D single crystals into DMF at a concentration 6%∼10% relative to the total weight. Spin-coat at 3000 rpm for 30 s on glass substrates. Anneal in air at 100 °C for 10 min before measurement.
Method: UV-Visible absorption
Description: Optical absorption spectra were obtained using a Shimadzu UV-3600 spectrophotometer.
Starting materials: Phenethylammonium lead iodide (PEALI) crystals, anhydrous acetonitrile (Acros Organics), sapphire substrates (Rayotek Scientific)
Product: Phenethylammonium lead iodide films
Description: PEALI crystals are dissolved by sonication in anhydrous acetonitrile at a concentration of 15 mg/mL. The solution is filtered through a 0.2 µm PTFE syringe filter (Pall Corporation) and spun on cleaned sapphire substrates by ramping the spin rate over 2 s to 2500 rpm and spinning for 10 s. After spin-casting, the films are annealed for 10 min at 80 ˚C. The entire process is carried out in a nitrogen-filled glove box.
Comment: Synthesis of PEALI crystals and cleaning procedure of the substrates can be found in the supporting information of the original publication
Method: UV-VIS Absorption
Description: The absorption spectra measurements of PEALI thin films were obtained by using Agilent Cary 5000 spectrophotometer.
Starting materials: Following Reference Ref. T. Ishihara, Optical Properties of Low-Dimensional Materials, edited by T. Ogawa and Y. Kanemitsu (World Scientific, Singapore, 1995), Chap. 6, pp. 289–339: Pbl2, 99.9% ~ 99.99%, phenethylamine, hydroiodic acid (HI) in aqueous solution. PbI2 needs to be distilled in vacuum (10^-2 - 10^3 Torr) at 400 degrees C, with the distillation process repeated several times, in order to remove residual impurities in 99.99% starting material.
Product: Phenethylammonium lead iodide crystals, prepared according to Ref. T. Ishihara, Optical Properties of Low-Dimensional Materials, edited by T. Ogawa and Y. Kanemitsu (World Scientific, Singapore, 1995), Chap. 6, pp. 289–339. That reference obtains orange platelets, typically 2x5x0.1 mm^3 in size.
Description: The undoped phenethyammonium lead iodide crystals (to which the data shown here pertains) were prepared according to Ref. T. Ishihara, Optical Properties of Low-Dimensional Materials, edited by T. Ogawa and Y. Kanemitsu (World Scientific, Singapore, 1995), Chap. 6, pp. 289–339. The present reference (doi: 10.1103/PhysRevB.70.205330) does not provide any further details on the synthesis of the undoped crystals in question. According to the 1995 reference, first synthesize phenethylammonium iodide (according to the reference, this is a simple modification of the syntesis of decylammonium iodide). Mix stoichiometric amounts of hydroiodic acid (aqueous solution) and phenethylamine in a beaker, cooled with ice, in oxygen-free atmosphere. Then, evaporate the water at elevated temperature. Sublime the material at 140 deg C to remove residual water, iodide and potentially other impurities. Then mix purified phenethylammonium iodide and lead iodide in acetone, heated up to 40 deg C. After reaction, filter to remove unreacted PbI2. Then precipitate phenethylammonium lead iodide single crystals by adding a poor solvent such as nitromethane. The full description of the synthesis is only provided for decylammonium lead iodide in the 1995 reference and the precipitation time of the crystals is stated to be 2-4 weeks.
Method: optical absorption measurement
Description: As a detector, a charge-coupled device (CCD) camera cooled by liquid nitrogen and equipped with a polychromator was utilized. A halogen lamp was used as a probe light for optical absorption measurements.
Comment: Note that only the onset of the absorption spectrum is shown, in line with the data shown in the original reference for undoped phenethyammonium lead iodide.
DOI for this data set: 10.1103/PhysRevB.70.205330
Data set ID: 1941 Did you find any mistakes or inconsistencies about this data? Send us a note and we'll have a look at it and send you a reply. Thanks!Starting materials: phenethylammonium iodide (C8H12IN), lead iodide (PbI2)
Product: thin film
Description: (PEA)I, amd PbI2 made up the target solution in 1:1 DMSO/MEG by volume. They were mechanically mixed until visibly dissolved in solvent, taking about 5 min. In a growth chamber, the solution is cooled to -196°C under vacuum. When frozen, the top layer is removed using an Er:YAG laser (2.94 μm). The laser rasters across the surface to sublimate the MEG, causing the precursor material to be ejected onto the substrate (2 cm × 2 cm of SiO2 glass) spinning 7 cm above. The substrate temperature is approximately 10 °C while in the growth chamber. Deposit time was 4 h. Samples remained in a load lock under turbo vacuum (2 × 10–5 Torr) for an hour afterwards. The annealed films were additionally annealed for 10 min on a hot plate in an N2 environment at 110°.
Method: UV-vis absorption
Description: UV−vis absorption spectra were acquired using a Shimadzu UV-3600 spectrophotometer. Samples of films on glass substrates were measured. Samples were kept in ambient air conditions.