The odd-even effect of alkyl chain in organic room temperature phosphorescence luminogens and the corresponding in vivo imaging

The odd-even effect is utilized to rationally design organic luminogens with the room temperature phosphorescence (RTP) effect. By just simply modifying the different alkyl substituents, the phenothiazine 5,5-dioxide derivatives exhibit totally different RTP properties, with the best performance achieved by CS-C3H7 having a phosphorescence lifetime of up to 327 ms. Furthermore, excitation-free phosphorescence imaging in living mice has been successfully realized, opening up a new avenue to promote the RTP effect in purely organic luminogens as well as the corresponding application in bio-imaging.