No gadget or software or App will do your learning for you; you have to get the right content into you brain where it can be applied and added to. Garbage in, is garbage out and information you abandon will fester - not die, but transmogrify or lay dormant.
There are both techniques and Apps that that help you to get 'stuff' into your brain.
Take good notes from lectures and books, including TED lectures and Internet based 'linear' content, as well as eBooks and multimedia.
Use your notes for essays
Use your essays and notes from which to revise
The ONLY App I have come across that has been tested with a randomized controlled trial and had a dozen or more papers published on it is a platform developed at Harvard Medical School, now called QStream, though developed and tested as 'Spaced-Ed'.
I'm writing this after a THREE HOUR stint from the early hours extricating and sorting 'digital' information from the computer into a format that my head can deal with: sheets of paper, cards, lists ...