Tunable room temperature phosphorescence and energy transfer in ratiometric co-crystals

Two co-crystals (BTA–ME-1 and BTA–ME-2) assembled with the same building blocks but in different ratios exhibit alternative stacking modes, relative orientations and aggregation states, leading to color-tunable green and yellow room temperature phosphorescence (RTP) and different intermolecular energy transfer efficiencies, respectively. Based on the time-resolved afterglow properties of the RTP emission, BTA–ME-2 is further applied for signal-visualized information encryption.