The photovoltaic method for the detection of liquid-phase photoionization in the absence of an applied electric field is compared to the traditional photoconductive method. Each system is characterized by means of signal and signal-to-noise ratio measurements with respect to laser pulse energy, applied voltage, electrode separation distance, solute concentration, and solvent composition. Although both techniques exhibit similar detection limits (1 × 10-7 M) for solutes in polar solvents such as methanol and water, the photovoltaic technique has a more extensive linear dynamic range (103). Moreover, this technique allows detection of solutes in ionic solutions with comparable detectability and linearity.
John W. Judge and Victoria L. McGuffin, "Comparative Study of Photovoltaic and Photoconductive Detection Methods for Liquid-Phase Photoionization," Appl. Spectrosc. 48, 1102-1110 (1994)