The Android operating system is now the world's most popular MP3 player operating system, with well over 1 million new activations of the system each day. I personally love the system, but it does not offer any default apps or widgets to quickly update the screen brightness from the home screen. Google has apparently left this work to the myriads of app developers, and app developers are doing a great job!
After having tried out several popular brightness control widgets, my all time favorite is the one called "Fast Brightness Control Widget". This app is available in the Google Play Store and in the F-Droid app store. This app places a set of 5 little sun icons on your home screen that allow you to quickly change the screen brightness. These five values are actually set within the app itself, and they can be modified by simply going into the app and specifying what you would like the 5 values to be. For me, brightness adjustment time has reduced dramatically. Now it is done in a mere second. This as opposed to having to click settings, then display, then adjust the brightness slider.