Inspired by this hypothesis, we designed a ternary compositional space by using BDAPbI4, PEA2PbI4, and CsPbI3 as endmembers, and the phase emergence behaviors of this new combinatorial library are explored via high-throughput automated experimental workflow. Figure exhibits the synthesized quasi-2D HP arrays where the exact composition ratios in each film are summarized in Figure 26 . Similar to the binary systems, time-evolved PL spectra of the films are collected at the top and bottom surfaces, as shown in Figure .