@meber-
No, sorry, a Roku TV has no provisions for outputting content to another device.
Some of the channels you view on Roku may have their own apps you can install on your phone and view them that way. And if you are in a country where The Roku Channel is supported, you can view it on your Roku mobile app, although you can't view any premium subscriptions you normally view thru The Roku Channel.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X