any app for sleep mode??

[nlsuelo13]

i was wondering if anyone knows of a app that puts your phone to sleep mode, only allowing text and phone calls nothing else with a push of a icon ?? Im trying to save as much battery as possible i have read some forums but im still getting ONLY from 6 am to 8pm with very little talking and a little texting .. i have set my battery to " battery saver" but know im wondering if i should set it to "smart mode" and change the setting to sleep in 15min and turn the screen to 20% but dont know if it would be better or not.. THANKS A LOT!!!!