A whole lot of hogwash in here - wrong units, dimensionally inconsistent equations, plain ridiculous or missing assumptions but still the post gets modded as insightful just because it *sounds* insightful.
- Larger pixels improve dynamic range. DR is defined as max signal before pixel saturation, divided by noise. Noise is limited by shot noise and electronics so does not scale with pixel size. Larger pixels have more signal range. So DR is higher.
- You calculate DR as if there is only one electron noise. Try several magnitudes higher noise! I am not sure DR is what you think it is.
- QE for most sensors is between 20% and 50%. 10% is nonsense.
- ISOCELL improves color rendition, it has nothing to do with sensitivity.
Following from Samsung should help -
According to Samsung, the ISOCELL sensor design achieves better image quality than is normally possible from the very small CMOS sensors used in smartphones and tablets. ISOCELL uses a backside-illuminated (BSI) photodiode that is unique compared to past designs thanks to its integrated barriers between the individual pixels. Compared to conventional BSI sensors, this reduces electrical crosstalk by about 30 percent. Crosstalk - the bleeding of photons and photoelectrons between neighboring pixels - has been a disadvantage of traditional BSI sensor design, one that can reduce image sharpness and color accuracy because light intended for one particular pixel spreads to its neighbors.
Existing BSI designs, with their photodiodes near the front of the sensor, lack any inherent structures that prevent light bleeding between pixels (a role fortuitously played by the circuitry in front of the photodiodes in older, frontside-illuminated chips). The barriers in the ISOCELL design prevent this bleeding.
How do you equate 10% QE to 5pLumens/pix "sensitivity"? I am not sure Sensitivity is what you think it is. Sensitivity is defined as voltage output from the sensor for a given light input. What is the voltage output assumed here? How does it compare to the camera noise?
Given this, rest of your statements do not make any sense either. When you say "generous" assumptions, it turns out they are actually ridiculous assumptions - you have removed the entire point of analysis and pixel size and even ignored reality, which is what the OP is commenting about. You disagreed with his points that are based on solid reality, but then ended up giving a half-baked proof derived from supposedly "fundamental" limits that are nowhere close to reality.