OLED display panels can display black pixels at almost no energy cost. As a result, using apps with more black would save the phone's battery. Google agrees, and more Android apps with a dark theme are being designed. Yesterday, at its Android Developer Summit in Mountain View yesterday, the company said what dramatic energy savings means when Dark Mode is used in its official apps on an OLED screen. At 50% brightness, the YouTube App's new Dark Mode interface saves a little less than 1
The technical breakdown of the developer conference can be seen in the following video.
Battery-saving black interfaces have been known for years – this is the reason why always ambient displays are available, as they were first seen on the Moto X and then by Google , Samsung and others were taken. This trick does not apply to LCD screens used in some low-cost designs (including the cheapest Android phones and the iPhone XR). Given that a large percentage of users through darker apps will sustain a significant battery life, and even those who will not appreciate the rest for their eyes, Google is pushing for more options for dark fashion in its own apps and encouraging developers
Although Google's default color scheme has used white as its base since the material design revision a few years ago, it looks like the company has planned to release more apps with the Dark Mode option like YouTube and the Standard app for Android phones. Pie, the latest Android operating system, offers a system-wide dark mode option: enable it by going to Display Preferences and tapping Device Theme.
Source: YouTube via Slashgear