All though the article main thrust is shooting the Milky Way with smart phones, it provides a pretty nice overview of the Smartphone technology. Especially interesting is this one passage on Sony sensor technology...
Quote: It’s considered a sixth generation Exmor sensor, three full generations newer than the best Sony sensors available in DLSRs and mirrorless cameras (Sony, Nikon, and Fujifilm cameras all use Sony sensors in some form or another). If you’re interested in reading about the evolution of Exmor technology, and why Sony has some of the best sensor technology on the market, check out this great article from Darren Bessette of Framos.
Essentially, without going too deep into details about the sensor, the Exmor RS sensor is significantly more efficient and sensitive and has the electronics architecture to produce images with less noise and better detail, per pixel, than the more conventional CMOS sensor designs found in most full size DSLRs and enthusiast cameras. In other words, the OnePlus One and other smartphones that use similar camera sensors are more technologically advanced designs than our large sensor cameras.
Here is a link to the Sony sensor article