Relationship between room temperature phosphorescence and deuteration position in a purely aromatic compound

• Published in: Chemical physics letters 2014-01, Vol.591, p.119-125
• Main Authors: Hirata, S., Totani, K., Watanabe, T., Kaji, H., Vacha, M.
• Format: Article
• Language: English
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2013.11.019

•We investigate influence of deuteration position to phosphorescence characteristics.•Deuteration at the lowest unoccupied molecular orbital (LUMO) enhanced triplet yield.•Deuteration at LUMO reduces the radiative and nonradiative rate of triplet excitons.•These result in large phosphorescence quantum yield and lifetime at room temperature. The development of organometallic and purely organic compounds showing room temperature phosphorescence (RTP) has several promising applications. We report a relationship between the phosphorescence characteristics and deuteration position in a purely organic aromatic compound. Hydrogen–deuterium exchange at the carbons where the lowest unoccupied molecular orbital is located is the most effective method to enhance the RTP lifetime and quantum yield. The increase in RTP lifetime comes from a decrease in the Franck–Condon factor while the enhancement of RTP yield is caused by an increase in intersystem crossing from the lowest singlet excited state to the lowest triplet excited state.