title: High Photoluminescence Quantum Yield in Band Gap Tunable Bromide Containing Mixed Halide Perovskites.
abstract: Hybrid organic-inorganic halide perovskite based semiconductor materials are attractive for use in a wide range of optoelectronic devices because they combine the advantages of suitable optoelectronic attributes and simultaneously low-cost solution processability. Here, we present a two-step low-pressure vapor-assisted solution process to grow high quality homogeneous CH3NH3PbI3-xBrx perovskite films over the full band gap range of 1.6-2.3 eV. Photoluminescence light-in versus light-out characterization techniques are used to provide new insights into the optoelectronic properties of Br-containing hybrid organic-inorganic perovskites as a function of optical carrier injection by employing pump-powers over a 6 orders of magnitude dynamic range. The internal luminescence quantum yield of wide band gap perovskites reaches impressive values up to 30%. This high quantum yield translates into substantial quasi-Fermi level splitting and high "luminescence or optically implied" open-circuit voltage. Most importantly, both attributes, high internal quantum yield and high optically implied open-circuit voltage, are demonstrated over the entire band gap range (1.6 eV ≤ Eg ≤ 2.3 eV). These results establish the versatility of Br-containing perovskite semiconductors for a variety of applications and especially for the use as high-quality top cell in tandem photovoltaic devices in combination with industry dominant Si bottom cells.
authors.affiliation: Electrical Engineering and Computer Sciences, University of California , Berkeley, California 94720, United States.
authors.forename: Carolin M
authors.initials: CM
authors.lastname: Sutter-Fella
authors.forename: Yanbo
authors.initials: Y
authors.lastname: Li
authors.affiliation: Electrical Engineering and Computer Sciences, University of California , Berkeley, California 94720, United States.
authors.forename: Matin
authors.initials: M
authors.lastname: Amani
authors.affiliation: Materials Science and Engineering, University of California , Berkeley, California 94720, United States.
authors.forename: Joel W
authors.initials: JW
authors.lastname: Ager
authors.forename: Francesca M
authors.initials: FM
authors.lastname: Toma
authors.affiliation: Electrical Engineering and Computer Sciences, University of California , Berkeley, California 94720, United States.
authors.forename: Eli
authors.initials: E
authors.lastname: Yablonovitch
authors.forename: Ian D
authors.initials: ID
authors.lastname: Sharp
authors.affiliation: Electrical Engineering and Computer Sciences, University of California , Berkeley, California 94720, United States.
authors.forename: Ali
authors.initials: A
authors.lastname: Javey
keywords: Halide perovskite; quantum yield; tandem device; wide band gap semiconductor