  Primordial Black Holes (PBHs) might have formed in the early Universe due to
the collapse of density fluctuations. PBHs may act as the sources for some of
the gravitational waves recently observed. We explored the formation scenarios
of PBHs of stellar mass, taking into account the possible influence of the QCD
phase transition, for which we considered three different models: Crossover
Model (CM), Bag Model (BM), and Lattice Fit Model (LFM). For the fluctuations,
we considered a running-tilt power-law spectrum; when these cross the $\sim
10^{-9}$-$10^{-1}\mathrm{~s}$ Universe horizon they originate
0.05-500~M$_{\odot}$ PBHs which could: i) provide a population of stellar mass
PBHs similar to the ones present on the binaries associated with all known
gravitational wave sources; ii) constitute a broad mass spectrum accounting for
$\sim 76\%$ of all Cold Dark Matter (CDM) in the Universe.
