  While nanoscale semiconductor crystallites provide versatile fluorescent
materials for light-emitting devices, such nanocrystals suffer from the "dark
exciton"$\unicode{x2014}$an optically inactive electronic state into which the
nanocrystal relaxes before emitting. Recently, a theoretical mechanism was
discovered that can potentially defeat the dark exciton. The Rashba effect can
invert the order of the lowest-lying levels, creating a bright excitonic ground
state. To identify materials that exhibit this behavior, here we perform an
extensive high-throughput computational search of two large open-source
materials databases. Based on a detailed understanding of the Rashba mechanism,
we define proxy criteria and screen over 500,000 solids, generating 173
potential "bright-exciton" materials. We then refine this list with
higher-level first-principles calculations to obtain 28 candidates. To confirm
the potential of these compounds, we select five and develop detailed
effective-mass models to determine the nature of their lowest-energy excitonic
state. We find that four of the five solids (BiTeCl, BiTeI, Ga$_2$Te$_3$, and
KIO$_3$) can yield bright ground-state excitons. Our approach thus reveals
promising materials for future experimental investigation of bright-exciton
nanocrystals.
