Several People on the World did'n Thing.
Several popular custom ROMs and root mods let you double tap the status bar at the top of your screen to put the phone to sleep. It pairs perfectly with the double tap to wake gesture you'll find on pretty much any Android phone. But if you're not rooted, you'll be glad to know you can finally do this by installing a simple app. This new app is from Tom Bayley, the developer of Bottom Quick Settings. Once it's configured properly, when you touch the status bar two times in quick succession, the screen will turn off. It's not faster than the power button, but it's a virtual touch interaction rather than a mechanical click, so it's more similar to the way you normally interact with the device and there's less wear and tear on your phone.