No, solar panels are integrated with the utility grid and will not operate if the grid is down. The reasons for this are both technical and regulatory.
From a technical perspective, as long as the sun is shining overhead, solar panels will generate power regardless of how much electricity your operation is actually consuming. In a grid-connected system, excess solar power is sent back into the grid for a credit, and any additional power you need beyond what your panels are producing is pulled from the grid. It’s a constant push/pull. Commercial solar aims to significantly reduce the amount of energy you need to purchase during the day, and in doing so, reduce operating expenses through a levelized cost of energy.
Safety regulations are the second reason. During outages, repair crews could be jeopardized if there is a local power generator (like a solar array) leaking power back into the grid lines. For this reason, utility rules mandate that solar arrays must automatically shut down during outages.