This larger size sensor allows it to capture more light and image for better low light pictures. (androidheadlines.com)
Doing so also helps reduce noise in low light pictures which is currently a problem with many smartphone cameras. (xda-developers.com)
The rear - facing camera has a 13MP sensor along with a large f / 2.0 aperture, which should mean that it performs well on low light pictures. (t3.com)