photonegative

[foh-tuh-neg-uh-tiv]
adjective Physics.
  1. pertaining to a substance, as selenium, having a conductivity that decreases upon absorption of electromagnetic radiation.

Origin of photonegative

First recorded in 1910–15; photo- + negative
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for photonegative

photonegative

adjective
  1. physics (of a material) having an electrical conductivity that decreases with increasing illumination
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012