During the Android Dev Summit 2018 event, Google, the host of the event in the United States, unveiled how Android device owners can do to save the battery.
What Google has commented is that there are colors that require more energy than others to be displayed on the screen and one is white. Thus, when using night mode for applications, battery consumption is significantly lower.
Google has set an example in this respect compared to the battery consumption of a Google Pixel device and an iPhone 7 with maximum brightness. In Pixel mode, night mode saves 63% of team energy while the iPhone 7, with the iOS operating system, consumes the same as normal mode.
The reason for this is that Android has a screen AMOLED, which almost does not consume batteries when it shows the black color, while LED screens use iOS, which do not depend on color for battery consumption. White is the color that consumes most of the battery in AMOLED screens, for which saving is enabled when night mode is activated.
The full show can be seen in this video: