The Baby Sleep White Noise Lullaby App for android is a good app that I use for my newborn to help him sleep at night and it works wonders.
https://play.google.com/store/apps/details?id=com.urbandroid.babysleep&hl=en_US
Also sometimes just singing some Lullabies yourself to your baby can help them sleep.
My mom used to sing me Lullabies herself and I fell asleep really fast when I was a baby.
There's lots of other apps in the link above for android to play lullabies and help your baby sleep.