Personal computers were supposed to all but eliminate the need for paper, but one look at your sticky-note-covered screen tells a different story. Researcher Tobias Große-Puppendahl may have created the perfect compromise, however: An electronic sticky note that can replace all of your little yellow reminders. To make them as easy to use as a pad of sticky Post-its, these tiny electronic displays never need to be charged. Instead, on the back you'll find a thin, flexible solar cell that harvests all the energy they need from indoor ambient lighting. There's a Bluetooth low-energy chip inside them too, so they can be wirelessly updated from a mobile device or a PC, and the same e-ink display technology as you'll find in ebook readers like the Kindle.
A solar cell several centimetres in size that's only exposed to indoor lighting doesn't generate a lot of electricity, so these electronic sticky notes utilise low-res e-ink displays that can only be updated and refreshed about once every minute in ideal conditions. You won't be using them to watch videos, and they can only display a couple of blocky characters at most. But they can still be a useful way to get a quick idea of how many unread emails are sitting in your inbox.
The wireless design of these tiny screens also means that they can be easily shared just like you would pass a sticky note onto a co-worker. The only drawback would be the price, but as long as the overnight cleaning crew doesn't throw them out, you can keep using these sticky notes as long as there's at least a little bit of light in your office.