SShutdown is a SSH command executor that allows you to shutdown your PC remotely. Since it connects with SSH no additional server is required, all you have to do is setup SSH access to your computer and authorize your mobile user to run certain commands like 'shutdown'. SSHutdown has a super simple user interface.
Prograssing is the developer of the app which can be found in the Tools category. The most recent update of this application was released on Dec 7, 2015 and SShutdown was downloaded by over 10K users. On Google Play, the app has been rated 3.5 by its users.