Fast Photochromism Discovered (IMAGE) Ritsumeikan University Caption Researchers have discovered fast-switching photochromism in an inexpensive inorganic material: copper-doped zinc sulfide nanocrystals. Their results pave the way for a plethora of potential applications ranging from smart adaptive windows and sunglasses to anti-counterfeiting agents. Credit Ritsumeikan University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.