Experimental photovoltaic (PV) cells have been constructed from a combination of semitransparent aluminum (alumina surface), polycrystalline organic dye, and silver backing electrodes. Working with merocyanine dyes familiar in photographic sensitization, these cells have given open-circuit voltages of 1.1 V and short-circuit current quantum efficiencies of 15 to 30%. The fill factors, which govern efficiency under load, are on the order of 0.25, and the operating lifetimes are not yet adequate. Individual dyes are compared as photovoltaic sensitizers and as silver bromide photoconductivity sensitizers. The electronic thresholds for Al absolute value Al/sub 2/O/sub 3/ dye and AgBr dye appear to be approximately equal. Since the dye packing structures are different (being three-dimensional crystals in the PV cells and close-packed monolayers on the AgBr surface), the absorption spectra differ grossly in form. The patterns of wavelength-dependent quantum yields also differ in the two applications. Field-dependent ionization sets an important limitation on many of the dyes in PV cells, as does the familiar drop of AgBr sensitization as monolayer coverage is exceeded. Ultimately one hopes for a synthesis of understanding of these two limitations, and even for a common solution. 8 figures, 1 table.