Solar PV is the technology which converts photons of solar irradiation directly to electricity using particular materials (such as silicon, cadmium telluride: CdTe, and a variety of others). It is what most people mean if they just talk about “solar power”, even though another technology exists: CSP, which instead collects and concentrates solar irradiation as heat, to drive a conventional thermal power generating cycle.
PV is currently the only electricity-generating source which doesn’t involve a spinning generator: which means solar PV panels/modules produce direct current (DC) rather than the alternating current (AC) produced by everything else. Hence a device called an inverter is required in order to convert to AC for feed-in to a grid (or household electricity circuit).
With no moving parts to wear and tear, PV is also characterised by a cost structure which is dominated by up-front capex and then, once built, very low opex. Hence as the costs of PV technology has seen dramatic falls, these capex decreases have passed directly through to similarly dramatic falls in the costs of energy from solar power projects (both using the LCOE metric and in terms of actual market prices).