In the first stage, three GAs are performed to find new NFAs. A building block unit library is prepared by fragmenting each NFA in the OPEP2 dataset, which contains 308 core units and 69 terminal units. First, GA 1 is designed to build NFAs with a fused core (4 or more fused rings) and terminal units. Similarly, GA 2 designs a fused core NFA with spacer units bridging the terminal units. Finally, GA 3 produces unfused NFAs, where each unit has less than 4 fused rings. In all three GA runs, each candidate NFA undergoes quantum mechanical calculations and its PCE is predicted using the ensemble RF and NN OPEP2 model. Since predicting PCE requires a donor material, each NFA is screened against the 214 donors in the OPEP2 dataset, and the highest PCE is selected as the maximum PCE for that NFA.