Despite modest charge carrier mobilities (3) and a known presence of defect sites (4), polycrystalline HOIP films prepared under comparatively crude conditions exhibit minority carrier lifetimes and diffusion lengths comparable with those of high-purity single-crystal GaAs (3). What makes HOIPs so special? On page 1409 of this issue, Zhu et al. (5) argue that the answer may lie in the rotational motion of the dipolar organic cations in the perovskite lattice. These motions seem to screen charge carriers from defects and other scattering potentials, much like ions screen electric fields in solution.
While known for their funky, soulful songs, The O'Jays often tackled social issues, as with "For the Love of Money" and "Put Your Hands Together," in which they urged "praying for all the people who are sleeping in the street." They had a hard time getting radio stations to play "Rich Get Richer," which argued: "The people who live on the hill/ Don't have time for the ghetto."
Microsoft's Groove apps for iOS and Android weren't quite as good as the Windows version, but this update was designed to change that. The company has given its music apps for both platforms a facelift that makes them look more like their Windows counterpart. It also bundled a handful of new features with it. The apps now have an Explore view listing the most popular songs, and they now take on a higher resolution when scaled up on big phones. Microsoft also promises faster downloads for offline playbacks and various improvements.
Smart music discovery playlists are all the rage right now (just ask Spotify), and Microsoft knows it. It recently introduced a Your Groove feature to Groove Music that automatically creates playlists suited to your taste. It'll generate track listings for your existing OneDrive music collection based on your listening habits, moods and artist activity, so you can revisit a favorite band when it's on tour. However, the real party starts when you have a Music Pass -- Groove will throw new songs into the playlists to expand your horizons.