[4ad]

Not really, the light flux is not really related to the physical aperture (diameter of the lens), but rather to the f-number of the lens (what photographers usually call "aperture" is in fact the f-number, focal length divided by lens aperture), an iPhone has an f/1.7 lens. This is an extremely fast lens, faster than any any zoom on a DSLR. Only dedicated prime lenses are faster.

The flux is:

    Φ/4α² * 1/A²

Total energy does depend on actual aperture though. Total power is:

    Φ/4πα * D²

Where D is a diameter of the lens.

As a first approximation, the sensor can support a certain flux, but once that regime is exceeded the damage is proportional to the energy, not to the flux. So if we talk about the regime where the sensor is not destroyed, flux is the relevant metric, but a larger lens will likely cause more damage once damage actually occurs.

[amluto]

This is just theoretical pontification, but I think there is a respect in which size matters: heat dissipation. Suppose you have a sensor laminated to a heat sink. If you apply some flux density (power per unit area) to a very small area (as would happen with a phone camera), you can dissipate heat in three dimensions: back toward the heat sink and to the sides through the rest of the sensor. If, in contrast, you apply the same flux density to a large area, the edge effects matter less and you approach the limit where heat only dissipates straight back. This could have a dramatic effect on the temperature.

A similar effect happens in the kitchen. It's very easy to burn yourself by touching a large hot surface, but it's much harder to burn yourself by touching a hot pointy thing.