It would help if you wrote complete sentences. Not sure what you are trying to find out. When I checked the ereader device listing in the wiki here on mobileread (
https://wiki.mobileread.com/wiki/E-book_devices), I see no dedicated ereader device using OLED). Maybe a tablet would use OLED, I don't know. Just google for it.
Mobileread has many things on the site, including an extensive library of ebooks in the public domain. Also our wiki has extensive information.