@article{CrovettoKojdaYietal.2022,
  author    = {Crovetto, Andrea and Kojda, Danny and Yi, Feng and Heinselman, Karen N. and LaVan, David A. and Habicht, Klaus and Unold, Thomas and Zakutayev, Andriy},
  title     = {Crystallize It before It diffuses},
  series = {Journal of the american chemical society},
  volume    = {144},
  journal   = {Journal of the american chemical society},
  number    = {29},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0002-7863},
  doi       = {10.1021/jacs.2c04868},
  pages     = {13334 -- 13343},
  year      = {2022},
  abstract  = {Numerous phosphorus-rich metal phosphides containing both P-P bonds and metal-P bonds are known from the solid-state chemistry literature. A method to grow these materials in thin-film form would be desirable, as thin films are required in many applications and they are an ideal platform for high-throughput studies. In addition, the high density and smooth surfaces achievable in thin films are a significant advantage for characterization of transport and optical properties. Despite these benefits, there is hardly any published work on even the simplest binary phosphorus-rich phosphide films. Here, we demonstrate growth of single-phase CuP2 films by a two-step process involving reactive sputtering of amorphous CuP2+x and rapid annealing in an inert atmosphere. At the crystallization temperature, CuP2 is thermodynamically unstable with respect to Cu3P and P-4. However, CuP2 can be stabilized if the amorphous precursors are mixed on the atomic scale and are sufficiently close to the desired composition (neither too P poor nor too P rich). Fast formation of polycrystalline CuP2, combined with a short annealing time, makes it possible to bypass the diffusion processes responsible for decomposition. We find that thin-film CuP2 is a 1.5 eV band gap semiconductor with interesting properties, such as a high optical absorption coefficient (above 10(5) cm(-1)), low thermal conductivity (1.1 W/(K m)), and composition-insensitive electrical conductivity (around 1 S/cm). We anticipate that our processing route can be extended to other phosphorus-rich phosphides that are still awaiting thin-film synthesis and will lead to a more complete understanding of these materials and of their potential applications.},
  language  = {en}
}
@article{LehmannFranzToebbensetal.2019,
  author    = {Lehmann, Frederike and Franz, Alexandra and Toebbens, Daniel M. and Levcenco, Sergej and Unold, Thomas and Taubert, Andreas and Schorr, Susan},
  title     = {The phase diagram of a mixed halide (Br, I) hybrid perovskite obtained by synchrotron X-ray diffraction},
  series = {RSC Advances},
  volume    = {9},
  journal   = {RSC Advances},
  number    = {20},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {2046-2069},
  doi       = {10.1039/c8ra09398a},
  pages     = {11151 -- 11159},
  year      = {2019},
  abstract  = {By using synchrotron X-ray powder diffraction, the temperature dependent phase diagram of the hybrid perovskite tri-halide compounds, methyl ammonium lead iodide (MAPbI3, MA+ = CH3NH3+) and methyl ammonium lead bromide (MAPbBr3), as well as of their solid solutions, has been established. The existence of a large miscibility gap between 0.29 ≤ x ≤ 0.92 (±0.02) for the MAPb(I1-xBrx)3 solid solution has been proven. A systematic study of the lattice parameters for the solid solution series at room temperature revealed distinct deviations from Vegard's law. Furthermore, temperature dependent measurements showed that a strong temperature dependency of lattice parameters from the composition is present for iodine rich compositions. In contrast, the bromine rich compositions show an unusually low dependency of the phase transition temperature from the degree of substitution.},
  language  = {en}
}