Perovskites The π-conjugated ionic compound QAPyBF4 was used as a perovskite modulator in the Research Article by Juin-Jei Liou, Taiho Park, Zong-Xiang Xu, and co-workers (e202117303). Experimental investigations showed that p-type conjugated cations [QAPy]2+ adsorb on surface with under-coordinated Pb highly electronegative [BF4]− anions enriched at SnO2 interface. This spontaneous diffusion e...