We perform modeling and dynamic simulations of all-semiconductor photonic crystal surface-emitting lasers (PCSELs). A two-dimensional photonic crystal consists of a GaAs layer with InGaP features, repeating periodically in both lateral directions. In our dynamic simulations, we demonstrate that photonic crystals with large isosceles triangular features, having a base angle close to 71.5°, enable suppression of higher-order modes and achieve single-mode lasing in large-area all-semiconductor PCSELs under moderate and high pump levels.