Organometal hybrid perovskites exhibit tunable absorption and photoluminescence spectra that originate from the adjustable excitons of the self-assembled quantum-well structures. The aggregation-induced emission (AIE) features of (RNH 3 ) 2 PbI 4 (R = alkyl, C n H 2 n +1 , n = 4, 12, 16, 18) as well as their reversible photoluminescence response to pH value are demonstrated.This interesting p…