@article{757c2417f0d847afa4bcc55999f5c332,
title = "Preparation of single-phase films of CH3NH3Pb(I 1- xBrx)3 with sharp optical band edges",
abstract = "Organometallic lead-halide perovskite-based solar cells now approach 18% efficiency. Introducing a mixture of bromide and iodide in the halide composition allows tuning of the optical bandgap. We prepare mixed bromide-iodide lead perovskite films CH3NH3Pb(I 1-xBrx)3 (0 ≤ x ≤ 1) by spin-coating from solution and obtain films with monotonically varying bandgaps across the full composition range. Photothermal deflection spectroscopy, photoluminescence, and X-ray diffraction show that following suitable fabrication protocols these mixed lead-halide perovskite films form a single phase. The optical absorption edge of the pure triiodide and tribromide perovskites is sharp with Urbach energies of 15 and 23 meV, respectively, and reaches a maximum of 90 meV for CH 3NH3PbI1.2Br1.8. We demonstrate a bromide-iodide lead perovskite film (CH3NH3PbI 1.2Br1.8) with an optical bandgap of 1.94 eV, which is optimal for tandem cells of these materials with crystalline silicon devices.",
keywords = "PDS, Urbach energy, iodide-bromide perovskite, organometallic lead halide perovskite",
author = "Aditya Sadhanala and Felix Deschler and Thomas, {Tudor H.} and Dutton, {Si{\^a}n E.} and Goedel, {Karl C.} and Hanusch, {Fabian C.} and Lai, {May L.} and Ullrich Steiner and Thomas Bein and Pablo Docampo and David Cahen and Friend, {Richard H.}",
year = "2014",
month = aug,
day = "7",
doi = "10.1021/jz501332v",
language = "אנגלית",
volume = "5",
pages = "2501--2505",
journal = "Journal of Physical Chemistry Letters",
issn = "1948-7185",
publisher = "American Chemical Society",
number = "15",
}