The New Technology That Could Someday Change $100 Bills

U.S. cash isn't actually made from paper. Instead, bills are made out of linen, cotton, and a host of security features — such as intricately woven red and blue fibers and security thread. Some of these security features are even invisible to the human eye without the aid of ultra-violet light. $100 bills, in particular, feature several special features that help prevent counterfeit bills. These special features are due both to the high worth of the note, and the fact that their primary purpose is storing monetary value rather than more everyday use (hence their longer average lifespan). These features can include microprinting and even raised printing texture. However, despite these measures, counterfeiters still often manage to fool people into accepting fake monetary notes. 

Luckily, in September 2025, scientists affiliated with the University of Colorado Boulder published a study in Nature Materials about the development of something known as a time crystal. These can be used to create something known as a "time watermark" that would make $100 bills, and other currency, significantly harder to counterfeit. If used in currency, banks and other users would be able to tell if a bill was legitimate by simply shining a light on it.

The scientists behind this breakthrough began by making the liquid crystals that are used in smart phone displays and LCD television screens act more like a solid. This means that, if you shine a light on them, the crystals will make certain repetitive patterns. Under a microscope, these created crystals can behave like a clock. Unlike other time crystals that been created in diamonds, quantum computers, and super-sized atoms, the crystals created by the CU Boulder scientists can be observed visually – which is why they could someday make an important impact on paper currency. 

Aside from anti-counterfeit measures these new crystals could also be used to store huge amounts of digital data. Ivan Smalyukh, professor of physics and co-author of the time crystal report, told CU Boulder Today, "We don't want to put a limit on the applications right now," before adding, "I think there are opportunities to push this technology in all sorts of directions." Should this technology ever be used in U.S. currency, don't worry about your old $100 bills. If your bank can redeem and salvage mutilated cash, then they can certainly accept your outdated money — assuming it's not counterfeit, that is.