The Collaborative International Dictionary of English v.0.48:

Photo-electric cell \Photo-electric cell\
   A cell (as one of two electrodes embedded in selenium) which
   by exposure to light generates an electric current.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

photoelectric cell
    n 1: a transducer used to detect and measure light and other
         radiations [syn: photoelectric cell, photoconductive
         cell, photocell, electric eye, magic eye]