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Luminous distant quasars are unique probes of the high redshift intergalacticmedium (IGM) and of the growth of massive galaxies and black holes in the earlyuniverse. Absorption due to neutral Hydrogen in the IGM makes quasars beyond aredshift of z~6.5 very faint in the optical $z$-band, thus locating quasars athigher redshifts require large surveys that are sensitive above 1 micron. Wereport the discovery of three new z>6.5 quasars, corresponding to an age of theuniverse of <850 Myr, selected as z-band dropouts in the Pan-STARRS1 survey.This increases the number of known z>6.5 quasars from 4 to 7. The quasars haveredshifts of z=6.50, 6.52, and 6.66, and include the brightest z-dropout quasarreported to date, PSO J036.5078+03.0498 with M_1450=-27.4. We obtainednear-infrared spectroscopy for the quasars and from the MgII line we estimatethat the central black holes have masses between 5x10^8 and 4x10^9 M_sun, andare accreting close to the Eddington limit (L_Bol/L_Edd=0.13-1.2). Weinvestigate the ionized regions around the quasars and find near zone radii ofR_NZ=1.5-5.2 proper Mpc, confirming the trend of decreasing near zone sizeswith increasing redshift found for quasars at 5.7<z<6.4. By combining R_NZ ofthe PS1 quasars with those of 5.7<z<7.1 quasars in the literature, we derive aluminosity corrected redshift evolution ofR_NZ,corrected=(7.2+/-0.2)-(6.1+/-0.7)x(z-6) Mpc. However, the large spread inR_NZ in the new quasars implies a wide range in quasar ages and/or a largevariation in the neutral Hydrogen fraction along different lines of sight.

The identification of z-dropouts in Pan-STARRS1: three quasars at 6.5