Lifetime and diffusion distance of singlet oxygen in air under everyday atmospheric conditions

Kang Kyun Wang, Sanggeun Song, Seung Jin Jung, Jung Wook Hwang, Min Goo Kim, Ji Hyun Kim, Jaeyoung Sung, Jin Kyu Lee, Yong Rok Kim

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Singlet oxygen is a toxic chemical but powerful oxidant, exploited in many chemical and biological applications. However, the lifetime of singlet oxygen in air under atmospheric conditions is yet to be known. This has limited safe usage of singlet oxygen in air, despite being a strong antimicrobial agent with the unique property of relaxing to breathable oxygen after serving its purpose. Here, we solve this long-standing problem by combining experimental and theoretical research efforts; we generate singlet oxygen using a photosensitizer at a local source and monitor the time-dependent extent of singlet oxygen reaction with probe molecules at a detector, precisely controlling the detector distance from the source. To explain our experimental results, we employ a theoretical model that fully accounts for singlet oxygen diffusion, radiative and nonradiative relaxations, and the bimolecular reaction with probe molecules at the detector. For all cases investigated, our model, with only two adjustable parameters, provides an excellent quantitative explanation of the experiment. From this analysis, we extract the lifetime of singlet oxygen in the air to be 2.80 s at 23 °C under 1 atm, during which time singlet oxygen diffuses about 0.992 cm. The correctness of this estimation is confirmed by a simple mean-first-passage time analysis of the maximum distance singlet oxygen can reach from the source. We also confirm the sterilization effects of singlet oxygen for distances up to 0.6-0.8 cm, depending on the bacteria strain in question, between the bacteria and the singlet oxygen source.

Original languageEnglish
Pages (from-to)21664-21671
Number of pages8
JournalPhysical Chemistry Chemical Physics
Issue number38
Publication statusPublished - 2020 Oct 14

Bibliographical note

Funding Information:
The authors gratefully acknowledge Professor Sang Kyu Kim at Korea Advanced Institute of Science and Technology, Professor Minhaeng Cho at Korea University, Professor Yuan-Chung Cheng at National Taiwan University, and Professor Jae Kyu Song at Kyung Hee University for helpful discussions. The authors are grateful to Mr. Luke Bates for his careful reading of the manuscript. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. NRF-2017R1A5A1015365, No. NRF-2016R1A2B4011155) and also by Creative Research Initiative Project program (2015R1A3A2066497) and the Priority Research Center Program (2009-0093817) funded by the NRF of Korea.

Publisher Copyright:
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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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