In contrast, DJ-spacer, BDA, exhibit different phase emergence behaviors. It is found that multiple 2D HP phases with n≥3 thicknesses emerge in the film matrix at the low 3D ratios, which separate from the n=1 2D HP (Figure ). These 2D HPs (e.g., n≥3) render a broad PL band ranging in 550-700 nm wavelength. The broadband PL becomes narrower with increasing the 3D ratio up to ~ 35%, which then gradually converge as a strong PL band ranging in 600-700 nm wavelength. Such trends were consistent with further increasing the 3D ratio up to 90%. Note that, in the overall compositional range, the peak position of the broadband PL peak constantly locates at the lower wavelengths than that of α-CsPbI3 (centered at ~700-710 nm) or 3D-like HP seen in BA counterpart. This suggests that, comparatively, the high-n HP phases constructed in BDA-based quasi-2D HP system are thinner than those in the system with RP spacers. We also note that the intensity of the broadband PL is even stronger than those of n=1 and 2 2D HPs. That is, BDA tends to manifest higher-n phases rather than intermediate 2D phases (e.g., n=2-4 2D HPs), allowing efficient charge transport through the non-confined HP lattices -beneficial to PV applications. However, distinct emergences of lower-n 2D HPs are observed across the compositional space after 10 hours (Figure ), suggesting that BDA cannot bestow sufficient phase stability to the quasi-2D HP lattices.