Freedom
One of the most useful productivity apps, Freedom helps you to focus more at work by closing down certain potentially distracting websites, allowing you to focus on work. You can choose which websites you don't want to see, and you can also control the length of time the sites are blocked off for, or even disable your browser altogether if you still cant focus.
Headspace
You can improve your performance and even your productivity, by using one of the productivity apps that incorporates mindfulness techniques into your daily routine. With just 10 minutes spent each day, Headspace can help you to achieve that much needed calmness and clarity.