In principle the absorption of light can cause an increase in the permittivity of a dielectric material, and hence in the capacity of a capacitor containing the material. Periodic interruption of the light can therefore cause the capacity to fluctuate, and, in the presence of an applied field, act as a generator of alternating current. In this paper we examine the likely magnitude of such a photodielectric effect and consider the thermodynamic, kinetic and photochemical factors likely to limit the efficiency of a solar conversion device employing it.

We conclude that a photodielectric device is attractive in principle because it circumvents some of the restraints encountered with conventional photovoltaic systems. However, for reasonable efficiency severe difficulties would have to be overcome. Chiefly these are that (1) the dipole moment of a molecule in the excited state of the dielectric material should exceed that of the ground state by more than 10 debye, (2) the excited state should have a long half-life and (3) the applied field strength should approach the breakdown value of known dielectrics.