  Majority and minority carrier properties such as type, density and mobility
represent fundamental yet difficult to access parameters governing
semiconductor device performance, most notably solar cells. Obtaining this
information simultaneously under light illumination would unlock many critical
parameters such as recombination lifetime, recombination coefficient, and
diffusion length; while deeply interesting for optoelectronic devices, this
goal has remained elusive. We demonstrate here a new carrier-resolved
photo-Hall technique that rests on a new identity relating hole-electron
mobility difference ($\Delta\mu$), Hall coefficient ($h$), and conductivity
($\sigma$): $\Delta\mu=(2+d\ln h/d\ln \sigma)\,h\,\sigma$, and a rotating
parallel dipole line ac-field Hall system with Fourier/lock-in detection for
clean Hall signal measurement. We successfully apply this technique to recent
world-record-quality perovskite and kesterite films and map the results against
varying light intensities, demonstrating unprecedented simultaneous access to
the above-mentioned parameters.
