It's fair to say that cameras are the point of fiercest competition in high-end smartphones, with Google, Samsung, and Apple constantly one-upping each other. Samsung is showing off its latest innovation, which it calls ISOCELL 2.0. The improved image sensor cells will allow more light to be isolated in each chamber.
It's a literally tiny change, just a shift in material on the bottom part of the barrier between each pixel. Samsung's promotional page claims that the new substance (which the company isn't detailing) is more reflective, allowing each divided section to absorb more light and thus more detail. It's a refinement of a feature that Samsung has been using for several years now. Samsung says it'll be using this new technique to cram even more pixel cells (read: cameras with bigger megapixel ratings) into the same space.
Exactly how much of a difference this change will make to camera quality is hard to gauge, especially since photo fidelity is becoming more dependent upon advanced software and less on the intricacies of the sensor and the lens. But we'll certainly be seeing this technology implemented on future Galaxy phones.