You need to make sure you are using a SlimPort supported phone/tablet. There is a listing on the SlimPort dot com website. No app is needed as it just mirrors your phone screen to a larger display. I have been using the Analogix SlimPort HDMI SP6001 with my Nexus 5 and LG G2 with no trouble at all.
SlimPort has something new with 4K output, the same as your phone. It's the NANO•CONSOLE. Check it out on Indiegogo
I have the SlimPort NANO•CONSOLE and it works great with my Nexus 5.