Back-side illuminated sensors? They have their advantages in that the active matrix is behind the photodiodes, but they have disadvantages too, such as cross-talk. Suffice it to say, the main advantages are greater when the pixels are smaller, otherwise the active matrix doesn’t reflect too much light away from the photodiodes with larger pixels. That being said, these kinds of sensors are a major boon to modern smartphones, but only used in some modern DSLR cameras.
20180814/https://en.wikipedia.org/wiki/Sony_α7R_II
20180814/https://en.wikipedia.org/wiki/Back-illuminated_sensor