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Ahmed MS, Nayak SK, Bhavani B, Banerjee D, Prasanthkumar S, Giribabu L, Soma VR, Raavi SSK. Hot carrier dynamics in metalated porphyrin-naphthalimide thin films. Phys Chem Chem Phys 2024; 26:15681-15692. [PMID: 38766760 DOI: 10.1039/d4cp00359d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
This study employs femtosecond transient absorption spectroscopy to investigate the rapid dynamics of excited state carriers in three metalated porphyrin-naphthalimide (PN) molecules and one free-base molecule. The dynamics of electron injection, from PN to mesoporous titania (TiO2), in PN adsorbed TiO2 films (Ti-PN), were carefully investigated and compared to PN adsorbed ZrO2 films (Zr-PN). In addition, we examined the self-assembled PN films and found that, in their self-assembled state, these molecules exhibited a longer relaxation time than Zr-PN monomeric films, where the charge injection channel was insignificant. The ground-state bleach band in the Ti-PN films gradually shifted to longer wavelengths, indicating the occurrence of the Stark effect. Faster electron injection was observed for the metalated PN systems and the electron injection times from the various excited states to the conduction band of TiO2 (CB-TiO2) were obtained from the target model analysis of the transient absorption spectra data matrix. In these metal-organic complexes, hot electron injection from PN to CB-TiO2 occurred on a time scale of <360 fs. Importantly, Cu(II)-based PN complexes exhibited faster injection and longer recombination times. The injection times have been estimated to result from a locally excited state at ≈280 fs, a hot singlet excited state at 4.95 ps, and a vibrationally relaxed singlet excited state at 97.88 ps. The critical photophysical and charge injection processes seen here provide the potential for exploring the underlying factors involved and how they correlate with photocatalytic performance.
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Affiliation(s)
- Md Soif Ahmed
- Ultrafast Photophysics and Photonics Laboratory, Department of Physics, Indian Institute of Technology Hyderabad, Kandi 502285, Telangana, India.
| | - Sudhanshu Kumar Nayak
- Ultrafast Photophysics and Photonics Laboratory, Department of Physics, Indian Institute of Technology Hyderabad, Kandi 502285, Telangana, India.
| | - Botta Bhavani
- Polymers & Functional Materials Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Dipanjan Banerjee
- Advanced Centre of Research in High Energy Materials (ACRHEM), DRDO Industry Academia - Centre of Excellence (DIA-COE), University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Seelam Prasanthkumar
- Polymers & Functional Materials Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Lingamallu Giribabu
- Polymers & Functional Materials Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Venugopal Rao Soma
- School of Physics, University of Hyderabad, Hyderabad 500046, Telangana, India
- Advanced Centre of Research in High Energy Materials (ACRHEM), DRDO Industry Academia - Centre of Excellence (DIA-COE), University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Sai Santosh Kumar Raavi
- Ultrafast Photophysics and Photonics Laboratory, Department of Physics, Indian Institute of Technology Hyderabad, Kandi 502285, Telangana, India.
- Department of Climate Change, Indian Institute of Technology Hyderabad, Kandi 502285, Telangana, India
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Zhang W, Ma Y, Song H, Miao R, Kong J, Zhou M. Deciphering the photophysical properties of naphthalimide derivatives using ultrafast spectroscopy. Phys Chem Chem Phys 2024; 26:4607-4613. [PMID: 38251277 DOI: 10.1039/d3cp05654f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Naphthalimide derivatives composed of donor-acceptor type structures hold significant promise across a wide range of applications. Here, the solvent polarity and viscosity controlled excited-state dynamics of a naphthalimide derivative with a donor-acceptor structure were studied using multiple spectroscopic techniques. From the stationary spectroscopic investigations, large Stokes shift and low fluorescence quantum yield were observed with increasing the solvent polarity, suggesting a more polar excited state relative to the ground state, which is evidenced by the Lippert-Mataga relationship. We also observe an enhanced fluorescence with a prolonged lifetime in a more viscous solution due to the restriction of excited-state molecular rearrangement. These observations result from the emerged twisted intramolecular charge transfer (TICT) state. The ultrafast spectroscopy studies further unravel a solvent polarity dependent excited state evolution from the intramolecular charge transfer state to the TICT state, revealing that the TICT state can be populated only in strong polar solvents. Control experiments by tuning the solvent viscosity in ultrafast experiments were employed to verify the excited state molecular rearrangement subsequently. These observations collectively emphasize how fine-tuning the photophysical properties of naphthalimide derivatives can be achieved through strategic manipulation of solvent polarity and viscosity.
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Affiliation(s)
- Wei Zhang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Anhui 230026, China.
| | - Yalei Ma
- Laboratory of Applied Surface and Colloids Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, P. R. China.
| | - Hongwei Song
- Department of Chemistry-Angstrom Laboratory, Uppsala University, Box 523, Uppsala 75120, Sweden
| | - Rong Miao
- Laboratory of Applied Surface and Colloids Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, P. R. China.
| | - Jie Kong
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Anhui 230026, China.
| | - Meng Zhou
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Anhui 230026, China.
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Xiao X, Mu T, Sukhanov AA, Zhou Y, Yu P, Yu F, Elmali A, Zhao J, Karatay A, Voronkova VK. The effect of thionation of the carbonyl group on the photophysics of compact spiro rhodamine-naphthalimide electron donor-acceptor dyads: intersystem crossing, charge separation, and electron spin dynamics. Phys Chem Chem Phys 2023; 25:31667-31682. [PMID: 37966808 DOI: 10.1039/d3cp04891h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
Herein, a spiro rhodamine (Rho)-thionated naphthalimide (NIS) electron donor-acceptor orthogonal dyad (Rho-NIS) was prepared to study the formation of a long-lived charge separation (CS) state via the electron spin control approach. The transient absorption (TA) spectra of Rho-NIS indicated that the intersystem crossing (ISC) occurs within 7-42 ps to produce the 3NIS state via the spin orbit coupling ISC (SOC-ISC). The energy order of 3CS (2.01 eV in n-hexane, HEX) and 3LE states (1.68 eV in HEX) depended on the solvent polarity. The 3NIS state having n-π* character and a lifetime of 0.38 μs was observed for Rho-NIS in toluene (TOL). Alternatively, in acetonitrile (ACN), the long-lived 3CS state (0.21 μs) with a high CS state quantum yield (ΦCS, 97%) was produced with the 3NIS state as the precursor and the CS took 134 ps. On the contrary, in the case of the reference Rho-naphthalimide (NI) Rho-NI dyad without thionation of its carbonyl group, a long-lived CS state (0.94 μs) with a high energy level (ECS = 2.12 eV) was generated even in HEX with a lower ΦCS (49%). In the presence of an acid, the Rho unit in the Rho-NIS adopted an open form (Rho-o) and the 3NIS state was produced within 24-47 ps with the 1Rho-o state as the precursor. Subsequently, slow intramolecular triplet-triplet energy transfer (TTET, 0.11-0.60 μs) produced the 3Rho-o state (9.4-13.6 μs). According to the time-resolved electron paramagnetic resonance (TREPR) spectra of NIS-NH2, the zero-field splitting (ZFS) parameter |D| and E of the triplet state were determined to be 6165 MHz and -1233 MHz, respectively, indicating that its triplet state has significant nπ* character, which was supported by its short triplet state lifetime (6.1 μs).
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Affiliation(s)
- Xiao Xiao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Rd., Dalian 116024, P. R. China.
| | - Tong Mu
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Rd., Dalian 116024, P. R. China.
| | - Andrey A Sukhanov
- Zavoisky Physical-Technical Institute FRC Kazan Scientific Center of RAS, Sibirsky Tract 10/7, Kazan 420029, Russia.
| | - Yihang Zhou
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Rd., Dalian 116024, P. R. China.
| | - Peiran Yu
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Rd., Dalian 116024, P. R. China.
| | - Fabiao Yu
- Key Laboratory of Hainan Trauma and Disaster Rescue, The First Affiliated Hospital of Hainan Medical University, Hainan Medical University, Haikou 571199, P. R. China
| | - Ayhan Elmali
- Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100, Ankara, Turkey.
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Rd., Dalian 116024, P. R. China.
| | - Ahmet Karatay
- Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100, Ankara, Turkey.
| | - Violeta K Voronkova
- Zavoisky Physical-Technical Institute FRC Kazan Scientific Center of RAS, Sibirsky Tract 10/7, Kazan 420029, Russia.
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