Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks
Room-temperature phosphorescent (RTP) materials have been attracting tremendous interest, owing to their unique material characteristics and potential applications for state-of-the-art optoelectronic devices. Recently, we reported the synthesis and fundamental photophysical properties of new RTP mat...
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MDPI AG
2020-09-01
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| Online Access: | https://www.mdpi.com/1996-1944/13/17/3904 |
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| author | Kaveendra Maduwantha Shigeyuki Yamada Kaveenga Rasika Koswattage Tsutomu Konno Takuya Hosokai |
| author_facet | Kaveendra Maduwantha Shigeyuki Yamada Kaveenga Rasika Koswattage Tsutomu Konno Takuya Hosokai |
| author_sort | Kaveendra Maduwantha |
| collection | DOAJ |
| description | Room-temperature phosphorescent (RTP) materials have been attracting tremendous interest, owing to their unique material characteristics and potential applications for state-of-the-art optoelectronic devices. Recently, we reported the synthesis and fundamental photophysical properties of new RTP materials based on benzil, i.e., fluorinated monobenzil derivative and fluorinated and non-fluorinated bisbenzil derivative analogues [Yamada, S. et al., Beilstein J. Org. Chem. 2020, 16, 1154–1162.]. To deeply understand their RTP properties, we investigated the excited-state dynamics and photostability of the derivatives by means of time-resolved and steady-state photoluminescence spectroscopies. For these derivatives, clear RTP emissions with lifetimes on the microsecond timescale were identified. Among them, the monobenzil derivative was found to be the most efficient RTP material, showing both the longest lifetime and highest amplitude RTP emission. Time-resolved photoluminescence spectra, measured at 77 K, and density functional theory calculations revealed the existence of a second excited triplet state in the vicinity of the first excited singlet state for the monobenzil derivative, indicative of the presence of a fast intersystem crossing pathway. The correlation between the excited state dynamics, emission properties, and conformational flexibility of the three derivatives is discussed. |
| first_indexed | 2024-03-10T16:35:42Z |
| format | Article |
| id | doaj.art-3e2d170926b247018d8e008c273f155c |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T16:35:42Z |
| publishDate | 2020-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-3e2d170926b247018d8e008c273f155c2023-11-20T12:29:24ZengMDPI AGMaterials1996-19442020-09-011317390410.3390/ma13173904Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil FrameworksKaveendra Maduwantha0Shigeyuki Yamada1Kaveenga Rasika Koswattage2Tsutomu Konno3Takuya Hosokai4Faculty of Graduate Studies, Sabaragamuwa University of Sri Lanka, P.O. Box 02, Belihuloya 70140, Sri LankaFaculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, JapanNational Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba 305-8565, JapanFaculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, JapanNational Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba 305-8565, JapanRoom-temperature phosphorescent (RTP) materials have been attracting tremendous interest, owing to their unique material characteristics and potential applications for state-of-the-art optoelectronic devices. Recently, we reported the synthesis and fundamental photophysical properties of new RTP materials based on benzil, i.e., fluorinated monobenzil derivative and fluorinated and non-fluorinated bisbenzil derivative analogues [Yamada, S. et al., Beilstein J. Org. Chem. 2020, 16, 1154–1162.]. To deeply understand their RTP properties, we investigated the excited-state dynamics and photostability of the derivatives by means of time-resolved and steady-state photoluminescence spectroscopies. For these derivatives, clear RTP emissions with lifetimes on the microsecond timescale were identified. Among them, the monobenzil derivative was found to be the most efficient RTP material, showing both the longest lifetime and highest amplitude RTP emission. Time-resolved photoluminescence spectra, measured at 77 K, and density functional theory calculations revealed the existence of a second excited triplet state in the vicinity of the first excited singlet state for the monobenzil derivative, indicative of the presence of a fast intersystem crossing pathway. The correlation between the excited state dynamics, emission properties, and conformational flexibility of the three derivatives is discussed.https://www.mdpi.com/1996-1944/13/17/3904room temperature phosphorescenceorganic moleculeexcited state dynamicstime-resolved photoluminescence spectroscopyphotostability |
| spellingShingle | Kaveendra Maduwantha Shigeyuki Yamada Kaveenga Rasika Koswattage Tsutomu Konno Takuya Hosokai Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks Materials room temperature phosphorescence organic molecule excited state dynamics time-resolved photoluminescence spectroscopy photostability |
| title | Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks |
| title_full | Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks |
| title_fullStr | Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks |
| title_full_unstemmed | Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks |
| title_short | Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks |
| title_sort | excited state dynamics of room temperature phosphorescent organic materials based on monobenzil and bisbenzil frameworks |
| topic | room temperature phosphorescence organic molecule excited state dynamics time-resolved photoluminescence spectroscopy photostability |
| url | https://www.mdpi.com/1996-1944/13/17/3904 |
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