51
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Paul S, Govind C, Karunakaran V. Planarity and Length of the Bridge Control Rate and Efficiency of Intramolecular Singlet Fission in Pentacene Dimers. J Phys Chem B 2020; 125:231-239. [PMID: 33371685 DOI: 10.1021/acs.jpcb.0c08590] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Singlet fission (SF) improves the power conversion efficiency of optoelectronic devices by converting high-energy photons into two triplet excitons. SF dynamics and efficiency (Φ) are controlled by various factors. Here, the effect of planarity and length of the bridge in pentacene dimers on the intramolecular SF (iSF) process was investigated by synthesizing the dimers connected by bridges having fluorene (FL-PD, planar), methyl-substituted biphenyl (MBP-PD, twisted), and diphenyl acetylene (DPA-PD, longer) groups and characterizing their excited-state relaxation dynamics using nanosecond and femtosecond pump-probe spectroscopy. Transient absorption studies reveal that iSF dynamics of FL-PD having a planar bridge are ∼787 times faster (187 ps) and exhibit higher Φ (198%) by feasible electronic coupling, compared to MBP-PD possessing a twisted bridge showing a low Φ of ∼16%. However compared to FL-PD, iSF dynamics of DPA-PD with an increase of bridge length are slower by an order (1.09 ns) and show comparable Φ of 185% through extended conjugation. Thus, the planarity and length of the bridge in pentacene dimers control the rate and efficiency of the iSF process.
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Affiliation(s)
- Sumitha Paul
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019 Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Chinju Govind
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019 Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Venugopal Karunakaran
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019 Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
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52
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Lv M, Yu Y, Sandoval‐Salinas ME, Xu J, Lei Z, Casanova D, Yang Y, Chen J. Engineering the Charge‐Transfer State to Facilitate Spin–Orbit Charge Transfer Intersystem Crossing in Spirobis[anthracene]diones. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009439] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Meng Lv
- State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai 200062 China
| | - Yang Yu
- Shanghai Key Laboratory of Chemical Biology School of Pharmacy Shanghai 200237 China
| | - María E. Sandoval‐Salinas
- Donostia International Physics Center (DIPC) 20018 Donostia Euskadi Spain
- Departament de Ciència de Materials i Química Física Institut de Química Teòrica i Computacional (IQTCUB) Universitat de Barcelona 08028 Barcelona Catalunya Spain
| | - Jianhua Xu
- State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai 200062 China
- Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan Shanxi 030006 China
| | - Zuhai Lei
- School of Pharmacy Fudan University Shanghai 200433 China
| | - David Casanova
- Departament de Ciència de Materials i Química Física Institut de Química Teòrica i Computacional (IQTCUB) Universitat de Barcelona 08028 Barcelona Catalunya Spain
- IKERBASQUE—Basque Foundation for Science 48011 Bilbao Euskadi Spain
| | - Youjun Yang
- Shanghai Key Laboratory of Chemical Biology School of Pharmacy Shanghai 200237 China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai 200062 China
- Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan Shanxi 030006 China
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53
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Fumanal M, Corminboeuf C. Direct, Mediated, and Delayed Intramolecular Singlet Fission Mechanism in Donor-Acceptor Copolymers. J Phys Chem Lett 2020; 11:9788-9794. [PMID: 33147966 DOI: 10.1021/acs.jpclett.0c03076] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Donor-acceptor (D-A) extended copolymers have shown great potential to be exploited for intramolecular singlet fission (iSF) because of their modular tunability and intrinsic ability to incorporate low-lying charge-transfer (CT) and a triplet-pair (1TT) states. While the SF mechanism has been widely debated in homo- and heterodimers, little is known about the singlet splitting process in A-D-A copolymer trimers. Unlike traditional two-site SF, the process of iSF in D-A copolymers involves three molecular units consisting of two A's and one D following an A-D-A polymeric chain. This scenario is, therefore, different from that of the homodimer analogues in terms of which states (if any) may drive the SF process. In this work, we identify how singlet splitting occurs in prototypical iSF D-A copolymer poly(benzodithiophene-alt-thiophene-1,1-dioxide) by means of wave packet propagations on the basis of the linear vibronic coupling model Hamiltonian. Our results reveal that three different mechanisms drive the S1 → 1TT population transfer via antisymmetric and symmetric vibrational motion, including two favorable mechanisms of direct and mediated interactions, as well as a parasitic decay pathway that potentially delays the process. Remarkably, we uncover the interplay between an upper state of marked multiexcitonic character and a low-lying CT state in balancing the splitting efficiency, which anticipates their major role in defining future guidelines for the molecular design of D-A copolymers for iSF.
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Affiliation(s)
- Maria Fumanal
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Clémence Corminboeuf
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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54
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Parenti KR, He G, Sanders SN, Pun AB, Kumarasamy E, Sfeir MY, Campos LM. Bridge Resonance Effects in Singlet Fission. J Phys Chem A 2020; 124:9392-9399. [PMID: 33138366 DOI: 10.1021/acs.jpca.0c08427] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A major benefit of intramolecular singlet fission (iSF) materials, in which through-bond interactions mediate triplet pair formation, is the ability to control the triplet formation dynamics through molecular engineering. One common design strategy is the use of molecular bridges to mediate interchromophore interactions, decreasing electronic coupling by increasing chromophore-chromophore separation. Here, we report how the judicious choice of aromatic bridges can enhance chromophore-chromophore electronic coupling. This molecular engineering strategy takes advantage of "bridge resonance", in which the frontier orbital energies are nearly degenerate with those of the covalently linked singlet fission chromophores, resulting in fast iSF even at large interchromophore separations. Using transient absorption spectroscopy, we investigate this bridge resonance effect in a series of pentacene and tetracene-bridged dimers, and we find that the rate of triplet formation is enhanced as the bridge orbitals approach resonance. This work highlights the important role of molecular connectivity in controlling the rate of iSF through chemical bonds and establishes critical design principles for future use of iSF materials in optoelectronic devices.
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Affiliation(s)
- Kaia R Parenti
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Guiying He
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, United States.,Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States
| | - Samuel N Sanders
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Andrew B Pun
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Elango Kumarasamy
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Matthew Y Sfeir
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, United States.,Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States
| | - Luis M Campos
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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55
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Wang L, Liu X, Shi X, Anderson CL, Klivansky LM, Liu Y, Wu Y, Chen J, Yao J, Fu H. Singlet Fission in a para-Azaquinodimethane-Based Quinoidal Conjugated Polymer. J Am Chem Soc 2020; 142:17892-17896. [DOI: 10.1021/jacs.0c06604] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Long Wang
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Xuncheng Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley 94720, United States
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Xiaomei Shi
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan 030001, China
| | - Christopher L. Anderson
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley 94720, United States
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Liana M. Klivansky
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley 94720, United States
| | - Yi Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley 94720, United States
| | - Yishi Wu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Junwu Chen
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Jiannian Yao
- Beijing National Laboratory for Molecules Science (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Hongbing Fu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, China
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56
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Pradhan E, Lee S, Choi CH, Zeng T. Diboron- and Diaza-Doped Anthracenes and Phenanthrenes: Their Electronic Structures for Being Singlet Fission Chromophores. J Phys Chem A 2020; 124:8159-8172. [PMID: 32902270 DOI: 10.1021/acs.jpca.0c06915] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We used quantum chemistry methods at the levels of mixed-reference spin-flip time-dependent density functional theory and multireference perturbation theory to study diboron- and diaza-doped anthracenes and phenanthrenes. This class of structures recently surged as potential singlet fission chromophores. We studied electronic structures of their excited states and clarified the reasons why they satisfy or fail to satisfy the energy criteria for singlet fission chromophores. Many studied structures have their S1 states not dominated by HOMO → LUMO excitation, so they cannot be described using the conventional two site model. This is attributed to frontier orbital energy shifts induced by the doping and different charge-transfer energies in different one-electron singlet excitations or, in other words, different polarizations of hole and/or particle orbitals in their S1 and T1 states. There is a mirror relation between the orbital energy shifts induced by diboron- and diaza-dopings, which together with alternant hydrocarbon pairings of occupied and unoccupied orbitals, leads to more mirror relations between the excited states of the two types of doped structures.
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Affiliation(s)
- Ekadashi Pradhan
- Department of Chemistry, York University, Toronto, Ontario M3J1P3, Canada
| | - Seunghoon Lee
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Cheol Ho Choi
- Department of Chemistry, Kyungpook National University, Daegu 702-701, South Korea
| | - Tao Zeng
- Department of Chemistry, York University, Toronto, Ontario M3J1P3, Canada
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57
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Nagami T, Tonami T, Okada K, Yoshida W, Miyamoto H, Nakano M. Vibronic coupling density analysis and quantum dynamics simulation for singlet fission in pentacene and its halogenated derivatives. J Chem Phys 2020; 153:134302. [DOI: 10.1063/5.0024746] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Takanori Nagami
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Takayoshi Tonami
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kenji Okada
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Wataru Yoshida
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Hajime Miyamoto
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Masayoshi Nakano
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
- Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
- Quantum Information and Quantum Biology Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Toyonaka, Osaka 560-8531, Japan
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58
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Engineering the Charge‐Transfer State to Facilitate Spin–Orbit Charge Transfer Intersystem Crossing in Spirobis[anthracene]diones. Angew Chem Int Ed Engl 2020; 59:22179-22184. [DOI: 10.1002/anie.202009439] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/12/2020] [Indexed: 12/18/2022]
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59
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Han J, Rehn DR, Buckup T, Dreuw A. Evaluation of Single-Reference DFT-Based Approaches for the Calculation of Spectroscopic Signatures of Excited States Involved in Singlet Fission. J Phys Chem A 2020; 124:8446-8460. [DOI: 10.1021/acs.jpca.0c07236] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Jie Han
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Dirk Robert Rehn
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Tiago Buckup
- Physikalisch Chemisches Institut, Universität Heidelberg, D-69120 Heidelberg, Germany
- Centre for Advanced Materials, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Andreas Dreuw
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Universität Heidelberg, D-69120 Heidelberg, Germany
- Centre for Advanced Materials, Universität Heidelberg, D-69120 Heidelberg, Germany
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60
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Nagami T, Miyamoto H, Yoshida W, Okada K, Tonami T, Nakano M. Theoretical Molecular Design of Phenanthrenes for Singlet Fission by Diazadibora-Substitution. J Phys Chem A 2020; 124:6778-6789. [PMID: 32786996 DOI: 10.1021/acs.jpca.0c05359] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Based on the valence configuration interaction (VCI) model and quantum chemical calculations, we theoretically investigate the potential of diazadibora-substituted phenanthrenes [(BN)2-phenanthrenes] as novel singlet fission (SF) chromophores. (BN)2-substitution to phenanthrene is performed to exhibit a captodative effect, which is found to enhance both diradical character and exchange integral. These enhanced parameters induced by (BN)2-substitution are shown to bring energetically favorable SF with high triplet excitation energies. In order to reveal the relationship between diradical character and positions replaced by (BN)2, analyses based on the VCI model, odd-electron density, and resonance structures are conducted. Accordingly, a concrete design principle, which is inherent in and is understandable from the topology of (BN)2-phenanthrene, is presented. Furthermore, design strategies to fine-tuning of the diradical character are newly demonstrated based on the additional introduction of π-donor and π-acceptor. The present results provide feasible candidate molecules and novel design strategies toward the discovery of bright SF chromophores for the application to efficient organic solar cells.
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Affiliation(s)
- Takanori Nagami
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Hajime Miyamoto
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Wataru Yoshida
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kenji Okada
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Takayoshi Tonami
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Masayoshi Nakano
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.,Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.,Center for Quantum Information and Quantum Biology Division (QIQB), Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Toyonaka, Osaka 560-8531, Japan
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61
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Pradhan E, Bentley JN, Caputo CB, Zeng T. Designs of Singlet Fission Chromophores with a Diazadiborinine Framework**. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.202000081] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Ekadashi Pradhan
- Department of Chemistry York University Toronto Ontario M3 J 1P3 Canada
| | - Jordan N. Bentley
- Department of Chemistry York University Toronto Ontario M3 J 1P3 Canada
| | | | - Tao Zeng
- Department of Chemistry York University Toronto Ontario M3 J 1P3 Canada
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62
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Singlet Fission in Self-assembled Amphipathic Tetracene Nanoparticles: Probing the Role of Charge-transfer State. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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63
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Zukun W, Wu R, Chen Z, Ye L, Li H, Zhu H. Ultrafast Electron Transfer Before Singlet Fission and Slow Triplet State Electron Transfer in Pentacene Single Crystal/C 60 Heterostructure. J Phys Chem A 2020; 124:4185-4192. [PMID: 32353232 DOI: 10.1021/acs.jpca.0c01791] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The singlet fission (SF) process converts one high-energy singlet exciton to two low-energy triplet excitons after absorbing one photon. Organic photovoltaic devices based on the SF process have shown great potential in solar energy conversion to exceed Shockley-Queisser limit. The key to SF photovoltaic devices requires efficient electron transfer (ET) from triplet exciton after SF, which is yet to be thoroughly investigated. Here, we performed thorough photophysical studies in 6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene)/C60 heterostructures using TIPS-pentacene microsize single crystal as a well-defined model system. We show the SF process in TIPS-pentacene single crystal occurs by a two-step process, with triplet pair intermediates forming in 75 fs and then dissociating to non-interacting triplets in 1.6 ps. The SF process in single crystal is comparable to that in polycrystalline film. Importantly, we observe a considerable fraction of singlet excitons is quenched by ultrafast (<75 fs) interfacial ET prior to fission and no ET from triplet excitons in 1.5 ns time window. We confirm that the absence of ET is not limited by exciton diffusion but due to very slow (≫1.5 ns) interfacial ET from triplet exciton. The observations contradict expected singlet and triplet ET behaviors based on a simple two-state Marcus ET model and suggest long-range interfacial ET from delocalized photoexcitation. The ultrafast ET from singlet exciton before SF and slow ET from triplet exciton call for reconsideration and careful design of efficient SF photovoltaic devices.
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Affiliation(s)
- Wang Zukun
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Ruihan Wu
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Zeng Chen
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Lei Ye
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Hanying Li
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Haiming Zhu
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
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64
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R S L, Kurup GB, Vennapusa SR. Identification of a receiver triplet state in the ultrafast intersystem crossing of carbonylpyrenes. Phys Chem Chem Phys 2020; 22:6145-6153. [PMID: 32124884 DOI: 10.1039/c9cp06857k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The near-unity triplet quantum yield of photoexcited carbonyl functionalized pyrenes is theoretically investigated. The estimated energetics of singlet-triplet manifolds and relevant spin-orbit coupling parameters strongly suggest triplet state formation via the S1→ T4/T5 pathway. Quantum wavepacket dynamics of triplet manifolds within the linear vibronic coupling approach reveal that the receiver triplet state would undergo rapid internal conversion decay to the lower triplet state(s), facilitating efficient triplet generation by minimizing the reverse intersystem crossing possibilities. On the basis of these results, a unified mechanism is proposed to describe the ultrafast intersystem crossing process in these molecules.
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Affiliation(s)
- Lekshmi R S
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Maruthamala P.O., Vithura, Thiruvananthapuram 695551, Kerala, India.
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65
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Wang L, Bai S, Wu Y, Liu Y, Yao J, Fu H. Revealing the Nature of Singlet Fission under the Veil of Internal Conversion. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201912202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Long Wang
- Beijing Key Laboratory for Optical Materials and Photonic DevicesDepartment of ChemistryCapital Normal University Beijing 100048 P. R. China
- Key Laboratory of Interface Science and Engineering in Advanced MaterialsMinistry of EducationTaiyuan University of Technology Taiyuan 030024 P. R. China
| | - Shuming Bai
- Department of ChemistryDuke University Durham NC 27708 USA
| | - Yishi Wu
- Beijing Key Laboratory for Optical Materials and Photonic DevicesDepartment of ChemistryCapital Normal University Beijing 100048 P. R. China
| | - Yanping Liu
- Beijing Key Laboratory for Optical Materials and Photonic DevicesDepartment of ChemistryCapital Normal University Beijing 100048 P. R. China
| | - Jiannian Yao
- Beijing Key Laboratory for Optical Materials and Photonic DevicesDepartment of ChemistryCapital Normal University Beijing 100048 P. R. China
- Institute of Molecular PlusSchool of Chemical Engineering and TechnologyTianjin UniversityCollaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 P. R. China
| | - Hongbing Fu
- Beijing Key Laboratory for Optical Materials and Photonic DevicesDepartment of ChemistryCapital Normal University Beijing 100048 P. R. China
- Institute of Molecular PlusSchool of Chemical Engineering and TechnologyTianjin UniversityCollaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 P. R. China
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66
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Mora‐Fuentes JP, Papadopoulos I, Thiel D, Álvarez‐Boto R, Cortizo‐Lacalle D, Clark T, Melle‐Franco M, Guldi DM, Mateo‐Alonso A. Singlet Fission in Pyrene‐Fused Azaacene Dimers. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201911529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Juan P. Mora‐Fuentes
- POLYMAT University of the Basque Country UPV/EHU Avenida de Tolosa 72 20018 Donostia-San Sebastian Spain
| | - Ilias Papadopoulos
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Dominik Thiel
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Roberto Álvarez‐Boto
- CICECO—Aveiro Institute of Materials Department of Chemistry University of Aveiro 3810-193 Aveiro Portugal
| | - Diego Cortizo‐Lacalle
- POLYMAT University of the Basque Country UPV/EHU Avenida de Tolosa 72 20018 Donostia-San Sebastian Spain
| | - Timothy Clark
- Computer-Chemistry Centre Department of Chemistry and Pharmacy Friedrich-Alexander-Universität Erlangen-Nürnberg Naegelsbachstr. 25 91052 Erlangen Germany
| | - Manuel Melle‐Franco
- CICECO—Aveiro Institute of Materials Department of Chemistry University of Aveiro 3810-193 Aveiro Portugal
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Aurelio Mateo‐Alonso
- POLYMAT University of the Basque Country UPV/EHU Avenida de Tolosa 72 20018 Donostia-San Sebastian Spain
- Ikerbasque Basque Foundation for Science Bilbao Spain
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67
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Mora‐Fuentes JP, Papadopoulos I, Thiel D, Álvarez‐Boto R, Cortizo‐Lacalle D, Clark T, Melle‐Franco M, Guldi DM, Mateo‐Alonso A. Singlet Fission in Pyrene-Fused Azaacene Dimers. Angew Chem Int Ed Engl 2020; 59:1113-1117. [PMID: 31647593 PMCID: PMC7687256 DOI: 10.1002/anie.201911529] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Indexed: 02/02/2023]
Abstract
Singlet fission has emerged as a promising strategy to avoid the loss of extra energy through thermalization in solar cells. A family of dimers consisting of nitrogen-doped pyrene-fused acenes that undergo singlet fission with triplet quantum yields as high as 125 % are presented. They provide new perspectives for nitrogenated polycyclic aromatic hydrocarbons and for the design of new materials for singlet fission.
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Affiliation(s)
- Juan P. Mora‐Fuentes
- POLYMATUniversity of the Basque Country UPV/EHUAvenida de Tolosa 7220018Donostia-San SebastianSpain
| | - Ilias Papadopoulos
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular MaterialsFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Dominik Thiel
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular MaterialsFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Roberto Álvarez‐Boto
- CICECO—Aveiro Institute of MaterialsDepartment of ChemistryUniversity of Aveiro3810-193AveiroPortugal
| | - Diego Cortizo‐Lacalle
- POLYMATUniversity of the Basque Country UPV/EHUAvenida de Tolosa 7220018Donostia-San SebastianSpain
| | - Timothy Clark
- Computer-Chemistry CentreDepartment of Chemistry and PharmacyFriedrich-Alexander-Universität Erlangen-NürnbergNaegelsbachstr. 2591052ErlangenGermany
| | - Manuel Melle‐Franco
- CICECO—Aveiro Institute of MaterialsDepartment of ChemistryUniversity of Aveiro3810-193AveiroPortugal
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular MaterialsFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Aurelio Mateo‐Alonso
- POLYMATUniversity of the Basque Country UPV/EHUAvenida de Tolosa 7220018Donostia-San SebastianSpain
- IkerbasqueBasque Foundation for ScienceBilbaoSpain
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68
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Uahengo V, Hamukwaya EN, Endjala PT, Naimhwaka JH. A potential naphthyl-thiazole-based organic dye and a ditopic chromogenic probe for CN − and Fe 3+ with molecular logic functions. NEW J CHEM 2020. [DOI: 10.1039/d0nj03806g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Dye sensitizers are entities designed primarily to serve the function of harvesting light photons in the functional wavelength, which is centered on charge transfer mechanisms.
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Affiliation(s)
- Veikko Uahengo
- Department of Chemistry and Biochemistry
- University of Namibia
- Windhoek
- Namibia
| | - Eunike N. Hamukwaya
- Department of Chemistry and Biochemistry
- University of Namibia
- Windhoek
- Namibia
| | - Paulina T. Endjala
- Department of Chemistry and Biochemistry
- University of Namibia
- Windhoek
- Namibia
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69
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Wang L, Bai S, Wu Y, Liu Y, Yao J, Fu H. Revealing the Nature of Singlet Fission under the Veil of Internal Conversion. Angew Chem Int Ed Engl 2019; 59:2003-2007. [PMID: 31729139 DOI: 10.1002/anie.201912202] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/02/2019] [Indexed: 11/07/2022]
Abstract
Singlet fission (SF) holds the potential to boost the maximum power conversion efficiency of photovoltaic devices. Internal conversion (IC) has been considered as one of the major competitive deactivation pathways to transform excitation energy into heat. Now, using time-resolved spectroscopy and theoretical calculation, it is demonstrated that, instead of a conventional IC pathway, an unexpected intramolecular singlet fission (iSF) process is responsible for excited state deactivation in isoindigo derivatives. The 1 TT state could form at ultrafast rate and nearly quantitatively in solution. In solid films, the slipped stacked intermolecular packing of a thiophene-functionalized derivative leads to efficient triplet pair separation, giving rise to an overall triplet yield of 181 %. This work not only enriches the pool of iSF-capable materials, but also contributes to a better understanding of the iSF mechanism, which could be relevant for designing new SF sensitizers.
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Affiliation(s)
- Long Wang
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing, 100048, P. R. China
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, P. R. China
| | - Shuming Bai
- Department of Chemistry, Duke University, Durham, NC, 27708, USA
| | - Yishi Wu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing, 100048, P. R. China
| | - Yanping Liu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing, 100048, P. R. China
| | - Jiannian Yao
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing, 100048, P. R. China
- Institute of Molecular Plus, School of Chemical Engineering and Technology, Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, P. R. China
| | - Hongbing Fu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing, 100048, P. R. China
- Institute of Molecular Plus, School of Chemical Engineering and Technology, Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, P. R. China
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70
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Wang L, Wu Y, Liu Y, Wang L, Yao J, Fu H. Morphology independent triplet formation in pentalene films: Singlet fission as the triplet formation mechanism. J Chem Phys 2019; 151:124701. [PMID: 31575178 DOI: 10.1063/1.5097192] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Singlet fission (SF), a spin-allowed multiexciton generation process, experienced renewed interest in the last decade due to its potential to increase the efficiency of photovoltaic devices. The hurdles now lie in the limited range of SF-capable materials and demanding morphology requirement for an efficient fission process. Although primary fission to yield triplet pair (1TT) can occur independently of film morphology in intramolecular singlet fission (iSF) materials, the separation of the 1TT state has been shown to be highly dependent on the packing motif and morphologies. In this work, we have demonstrated that both iSF and triplet pair separation processes took place irrelevant of molecular order and/or film morphology in a series of pentalene compounds. With the >180% fission efficiency, the suitable triplet energy levels, and the long lifetime of the triplet excitons, these iSF systems can be integrated into practical photovoltaic application.
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Affiliation(s)
- Long Wang
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Yishi Wu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Yanping Liu
- Beijing National Laboratory for Molecules Science (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species and Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Lanfen Wang
- Beijing National Laboratory for Molecules Science (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species and Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiannian Yao
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Hongbing Fu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, China
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71
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Huang H, He G, Xu K, Wu Q, Wu D, Sfeir MY, Xia J. Achieving Long-Lived Triplet States in Intramolecular SF Films through Molecular Engineering. Chem 2019. [DOI: 10.1016/j.chempr.2019.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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72
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Pun AB, Asadpoordarvish A, Kumarasamy E, Tayebjee MJY, Niesner D, McCamey DR, Sanders SN, Campos LM, Sfeir MY. Ultra-fast intramolecular singlet fission to persistent multiexcitons by molecular design. Nat Chem 2019; 11:821-828. [PMID: 31406323 DOI: 10.1038/s41557-019-0297-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 06/14/2019] [Indexed: 11/10/2022]
Abstract
Singlet fission-that is, the generation of two triplets from a lone singlet state-has recently resurfaced as a promising process for the generation of multiexcitons in organic systems. Although advances in this area have led to the discovery of modular classes of chromophores, controlling the fate of the multiexciton states has been a major challenge; for example, promoting fast multiexciton generation while maintaining long triplet lifetimes. Unravelling the dynamical evolution of the spin- and energy conversion processes from the transition of singlet excitons to correlated triplet pairs and individual triplet excitons is necessary to design materials that are optimized for translational technologies. Here, we engineer molecules featuring a discrete energy gradient that promotes the migration of strongly coupled triplet pairs to a spatially separated, weakly coupled state that readily dissociates into free triplets. This 'energy cleft' concept allows us to combine the amplification and migration processes within a single molecule, with rapid dissociation of tightly bound triplet pairs into individual triplets that exhibit lifetimes of ~20 µs.
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Affiliation(s)
- Andrew B Pun
- Department of Chemistry, Columbia University, NewYork, NY, USA
| | - Amir Asadpoordarvish
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
| | | | - Murad J Y Tayebjee
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.,School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales, Australia
| | - Daniel Niesner
- Department of Chemistry, Columbia University, NewYork, NY, USA.,Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, MA, USA
| | - Dane R McCamey
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
| | - Samuel N Sanders
- Department of Chemistry, Columbia University, NewYork, NY, USA. .,Rowland Institute at Harvard, Cambridge, MA, USA.
| | - Luis M Campos
- Department of Chemistry, Columbia University, NewYork, NY, USA.
| | - Matthew Y Sfeir
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, MA, USA. .,Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, USA. .,Department of Physics, Graduate Center, City University of New York, New York, NY, USA.
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73
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Allardice JR, Thampi A, Dowland S, Xiao J, Gray V, Zhang Z, Budden P, Petty AJ, Davis NJLK, Greenham NC, Anthony JE, Rao A. Engineering Molecular Ligand Shells on Quantum Dots for Quantitative Harvesting of Triplet Excitons Generated by Singlet Fission. J Am Chem Soc 2019; 141:12907-12915. [PMID: 31336046 PMCID: PMC7007228 DOI: 10.1021/jacs.9b06584] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
Singlet
fission is an exciton multiplication process in organic
molecules in which a photogenerated spin-singlet exciton is rapidly
and efficiently converted to two spin-triplet excitons. This process
offers a mechanism to break the Shockley–Queisser limit by
overcoming the thermalization losses inherent to all single-junction
photovoltaics. One of the most promising methods to harness the singlet
fission process is via the efficient extraction of the dark triplet
excitons into quantum dots (QDs) where they can recombine radiatively,
thereby converting high-energy photons to pairs of low-energy photons,
which can then be captured in traditional inorganic PVs such as Si.
Such a singlet fission photon multiplication (SF-PM) process could
increase the efficiency of the best Si cells from 26.7% to 32.5%,
breaking the Shockley–Queisser limit. However, there has been
no demonstration of such a singlet fission photon multiplication (SF-PM)
process in a bulk system to date. Here, we demonstrate a solution-based
bulk SF-PM system based on the singlet fission material TIPS-Tc combined
with PbS QDs. Using a range of steady-state and time-resolved measurements
combined with analytical modeling we study the dynamics and mechanism
of the triplet harvesting process. We show that the system absorbs
>95% of incident photons within the singlet fission material to
form
singlet excitons, which then undergo efficient singlet fission in
the solution phase (135 ± 5%) before quantitative harvesting
of the triplet excitons (95 ± 5%) via a low concentration of
QD acceptors, followed by the emission of IR photons. We find that
in order to achieve efficient triplet harvesting it is critical to
engineer the surface of the QD with a triplet transfer ligand and
that bimolecular decay of triplets is potentially a major loss pathway
which can be controlled via tuning the concentration of QD acceptors.
We demonstrate that the photon multiplication efficiency is maintained
up to solar fluence. Our results establish the solution-based SF-PM
system as a simple and highly tunable platform to understand the dynamics
of a triplet energy transfer process between organic semiconductors
and QDs, one that can provide clear design rules for new materials.
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Affiliation(s)
- Jesse R Allardice
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Arya Thampi
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Simon Dowland
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - James Xiao
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Victor Gray
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom.,Department of Chemistry, Ångström Laboratory , Uppsala University , Box 532, Uppsala SE-751 20 , Sweden
| | - Zhilong Zhang
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Peter Budden
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Anthony J Petty
- Center for Applied Energy Research , University of Kentucky , Research Park Drive , Lexington , Kentucky 40511 , United States
| | - Nathaniel J L K Davis
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom.,The MacDiarmid Institute for Advanced Materials and Nanotechnology, The Dodd-Walls Centre for Photonic and Quantum Technologies, School of Chemical and Physical Sciences , Victoria University of Wellington , Wellington 6140 , New Zealand
| | - Neil C Greenham
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - John E Anthony
- Center for Applied Energy Research , University of Kentucky , Research Park Drive , Lexington , Kentucky 40511 , United States
| | - Akshay Rao
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
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74
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Reddy SR, Coto PB, Thoss M. Quantum dynamical simulation of intramolecular singlet fission in covalently coupled pentacene dimers. J Chem Phys 2019; 151:044307. [DOI: 10.1063/1.5109897] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- S. Rajagopala Reddy
- Institute of Physics, Albert-Ludwigs University Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Pedro B. Coto
- Department of Physical and Analytical Chemistry, University of Oviedo, Avda. Julián Clavería 8, 33006, Oviedo, Spain
| | - Michael Thoss
- Institute of Physics, Albert-Ludwigs University Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
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75
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Datko BD, Grimm R, Walwark DJ, Burnside B, Grey JK. Resolving population dynamics and interactions of multiple triplet excitons one molecule at a time. J Chem Phys 2019; 151:044203. [PMID: 31370535 DOI: 10.1063/1.5099920] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Resolving the population dynamics of multiple triplet excitons on time scales comparable to their lifetimes is a key challenge for multiexciton harvesting strategies, such as singlet fission. We show that this information can be obtained from fluorescence quenching dynamics and stochastic kinetic modeling simulations of single nanoparticles comprising self-assembled aggregated chains of poly(3-hexylthiophene) (P3HT). These multichromophoric structures exhibit the elusive J-aggregate type excitonic coupling leading to delocalized intrachain excitons that undergo facile triplet formation mediated by interchain charge transfer states. We propose that P3HT J-aggregates can serve as a useful testbed for elucidating the presence of multiple triplets and understanding factors governing their interactions over a broad range of time scales. Stochastic kinetic modeling is then used to simulate discrete population dynamics and estimate higher order rate constants associated with triplet-triplet and singlet-triplet annihilation. Together with the quasi-CW nature of the experiment, the model reveals the expected amounts of triplets at equilibrium per molecule. Our approach is also amenable to a variety of other systems, e.g., singlet fission active molecular arrays, and can potentially inform design and optimization strategies to improve triplet harvesting yields.
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Affiliation(s)
- Benjamin D Datko
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Ryan Grimm
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - David J Walwark
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Brandon Burnside
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - John K Grey
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
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76
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Japahuge A, Lee S, Choi CH, Zeng T. Design of singlet fission chromophores with cyclic (alkyl)(amino) carbene building blocks. J Chem Phys 2019; 150:234306. [PMID: 31228896 DOI: 10.1063/1.5099062] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We use MRSF-TDDFT and NEVPT2 methods to design singlet fission chromophores with the building blocks of cyclic (alkyl)(amino)carbenes (CAACs). CAAC dimers with C2, C4, and p-phenylene spacers are considered. The substitutions with trifluoromethyls and fluorine atoms at the α C position are investigated. The electronegative substituents enhance the π accepting capability of the α C while maintaining it as a quaternary C atom. The phenylene-connected dimers with the two substitutions are identified as promising candidates for singlet fission chromophores. The cylindrically symmetric C2 and C4 spacers allow for substantial structural reorganizations in the S0-to-S1 and S0-to-T1 excitations. Although the two substituted dimers with the C4 spacer satisfy (or very close to satisfy) the primary thermodynamics criterion for singlet fission, the significant structural reorganizations result in high barriers so that the fission is kinetically unfavorable.
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Affiliation(s)
- Achini Japahuge
- Department of Chemistry, Carleton University, Ottawa, Ontario K1S5B6, Canada
| | - Seunghoon Lee
- Department of Chemistry, Seoul National University, Seoul 151-747, South Korea
| | - Cheol Ho Choi
- Department of Chemistry, Kyungpook National University, Daegu 702-701, South Korea
| | - Tao Zeng
- Department of Chemistry, Carleton University, Ottawa, Ontario K1S5B6, Canada
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77
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Sanders SN, Gangishetty MK, Sfeir MY, Congreve DN. Photon Upconversion in Aqueous Nanodroplets. J Am Chem Soc 2019; 141:9180-9184. [DOI: 10.1021/jacs.9b03992] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Samuel N. Sanders
- Rowland Institute at Harvard, Cambridge, Massachusetts 02142, United States
| | | | - Matthew Y. Sfeir
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, United States
| | - Daniel N. Congreve
- Rowland Institute at Harvard, Cambridge, Massachusetts 02142, United States
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78
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Efficient triplet pair separation from intramolecular singlet fission in dibenzopentalene derivatives. Sci China Chem 2019. [DOI: 10.1007/s11426-019-9482-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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79
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Willems RM, Meskers SCJ, Wienk MM, Janssen RAJ. Effect of Charge-Transfer State Energy on Charge Generation Efficiency via Singlet Fission in Pentacene-Fullerene Solar Cells. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2019; 123:10253-10261. [PMID: 31049121 PMCID: PMC6488139 DOI: 10.1021/acs.jpcc.9b00568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 03/24/2019] [Indexed: 06/01/2023]
Abstract
Singlet fission in pentacene creates two triplet excitons per absorbed photon. In a solar cell, each triplet can generate an electron-hole pair, and hence, external quantum efficiencies exceeding 100% have been reported for pentacene-fullerene solar cells. The energetics of this process are intriguing because the minimum photon energy loss, defined as the energy difference between the (triplet) exciton state and the open-circuit voltage, is less than 0.5 eV and distinctively smaller than that in most organic donor-acceptor solar cells. To investigate the energetics of this process, we analyze the effect of the energy of the lowest unoccupied molecular orbital (LUMO) for different fullerene derivatives. With the LUMO energy becoming less negative, the open-circuit voltage increases and charge generation decreases. For all but one of the fullerenes tested, the charge-transfer state energy is distinctively higher than the pentacene triplet energy, revealing that charge generation via singlet fission is actually endergonic. An elementary Marcus model for the rate of electron transfer provides a qualitative description of the experimental trends, in accordance with an endergonic charge transfer. Considering that charge generation from triplet states is endergonic, involvement of pentacene singlet states, either from direct photoexcitation or via triplet-triplet annihilation, cannot be excluded.
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Affiliation(s)
- Robin
E. M. Willems
- Molecular
Materials and Nanosystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Stefan C. J. Meskers
- Molecular
Materials and Nanosystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Martijn M. Wienk
- Molecular
Materials and Nanosystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - René A. J. Janssen
- Molecular
Materials and Nanosystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Dutch
Institute for Fundamental Energy Research, De Zaale 20, 5612
AJ Eindhoven, The Netherlands
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80
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81
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Datko BD, Livshits M, Zhang Z, Qin Y, Jakubikova E, Rack JJ, Grey JK. Large Excited-State Conformational Displacements Expedite Triplet Formation in a Small Conjugated Oligomer. J Phys Chem Lett 2019; 10:1259-1263. [PMID: 30811200 DOI: 10.1021/acs.jpclett.9b00495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Intersystem crossing in conjugated organic molecules is most conveniently viewed from pure electronic perspectives; yet, vibrational displacements may often drive these transitions. We investigate an alkyl-substituted thienylene-vinylene dimer (dTV) displaying efficient triplet formation. Steady-state electronic and Raman spectra display large Stokes shifts (∼4000 cm-1) involving high-frequency skeletal symmetric stretching modes (∼900-1600 cm-1) in addition to large displacements of low-frequency torsional motions (∼300-340 cm-1). Transient absorption spectroscopy reveals the emergence of distorted singlet (S1) and triplet signatures following initial vibrational relaxation dynamics that dominate spectral dynamics on time scales > 100 ps, with the latter persisting on time scales up to ca. 7 μs. Potential energy surfaces calculated along the dominant displaced out-of-plane torsional mode reveal shallow energy barriers for entering the triplet manifold from S1. We propose that dTV is a good model system for understanding vibrational contributions to intersystem crossing events in related polymer systems.
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Affiliation(s)
- Benjamin D Datko
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Maksim Livshits
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Zhen Zhang
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Yang Qin
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Elena Jakubikova
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Jeffrey J Rack
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - John K Grey
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
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82
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Abstract
Excimers play an important role in photochemical processes ranging from singlet fission to DNA damage, and the characteristic red-shift in fluorescence spectra associated with excimer formation can provide information about aggregate formation and the orientation of chromophores. When a mixture of chromophores is present, exciplex formation may lead to spectral characteristics distinct from those of either monomer or the corresponding excimers. To predict the effects of aggregation in a system containing a mixture of small acenes, binding energies and minimum-energy geometries have been calculated for three mixed S1 exciplexes. Benchmark CASSCF/NEVPT2 multireference binding energies of 18.2, 27.7, and 49.3 kJ/mol are reported for the benzene-naphthalene, benzene-anthracene, and naphthalene-anthracene exciplexes, respectively. TDDFT calculations have been performed using a range of exchange-correlation functionals, showing that many functionals perform inconsistently, and the error in binding energy often depends on the character of the monomer excitation from which the exciplex state is derived. Moderate exciplex stabilization observed for the benzene-naphthalene and naphthalene-anthracene exciplexes results from a mixture of charge transfer and exciton delocalization.
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83
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Datko BD, Grey JK. Population dynamics of multiple triplet excitons revealed from time-dependent fluorescence quenching of single conjugated polymer chains. Sci Rep 2019; 9:817. [PMID: 30692627 PMCID: PMC6349865 DOI: 10.1038/s41598-018-37477-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/02/2018] [Indexed: 01/02/2023] Open
Abstract
The advent of multiple exciton harvesting schemes and prolonging exciton lifetimes to improve performance attributes of solar cells based on conjugated organic materials presents some interesting challenges that must be overcome in order to realize the full potential of these strategies. This is especially important for applications involving multi-chromophoric conjugated polymers where interactions between multiple spin-forbidden triplet excitons can be significant and are mediated by chain conformation. We use single molecule spectroscopic techniques to investigate interactions between multiple triplet excitons and emissive singlets by monitoring time-dependent fluorescence quenching on time scales commensurate with the triplet lifetime. Structurally related conjugated polymers differing by heteroatom substitution were targeted and we use a stochastic photodynamic model to numerically simulate the evolution of multi-exciton populations following photoexcitation. Single chains of poly(3-hexylthiophene) (P3HT) exhibit longer-lived triplet dynamics and larger steady-state triplet occupancies compared to those of poly(3-hexylselenophene) (P3HS), which has a larger reported triplet yield. Triplet populations evolve and relax much faster in P3HS which only becomes evident when considering all kinetic factors governing exciton population dynamics. Overall, we uncover new guidelines for effectively managing multi-exciton populations and interactions in conjugated polymers and improving their light harvesting efficiency.
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Affiliation(s)
- Benjamin D Datko
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - John K Grey
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM, 87131, USA.
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84
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Aguilar Suarez LE, Kathir R, Siagri E, Havenith RW, Faraji S. Determination of electronic couplings in the singlet fission process using a nonorthogonal configuration interaction approach. STATE OF THE ART OF MOLECULAR ELECTRONIC STRUCTURE COMPUTATIONS: CORRELATION METHODS, BASIS SETS AND MORE 2019. [DOI: 10.1016/bs.aiq.2019.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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85
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Krueger RA, Blanquart G. Predicting aromatic exciplex fluorescence emission energies. Phys Chem Chem Phys 2019; 21:10325-10335. [DOI: 10.1039/c9cp02027f] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Analysis of PAH exciplex TDDFT fluorescence energies shows a linear relationship between the mean monomer HOMO–LUMO gap and complex fluorescence.
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Affiliation(s)
- Rachel A. Krueger
- Department of Chemistry
- The California Institute of Technology
- Pasadena
- USA
| | - Guillaume Blanquart
- Department of Mechanical and Civil Engineering
- The California Institute of Technology
- Pasadena
- USA
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86
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Abstract
The highly unusual state, 1(TT), is a coupled, double triplet state that has recently garnered significant attention. This multiexcitonic state can be formed by a quantum transition from a single-photon bright state in a variety of organic semiconducting materials. 1(TT)'s transient nature and similarity to independent triplets, however, has led to significant difficulties in characterization and prediction of its properties. Recent progress describing 1(TT) from theory and experiment are breaking through these difficulties, and have greatly advanced our comprehension of this state. Starting from the early description of 1(TT) in polyenes, this perspective discusses formation mechanisms, spectroscopic signatures, and the scope of intertriplet interactions. When employing singlet fission to generate charge carriers in a solar cell, 1(TT) has a central role. Due to the variety of coupling strengths between triplet states in 1(TT) amongst different chromophores, two different strategies are discussed to enable efficient charge carrier extraction. Continued growth in our understanding of 1(TT) may lead to control over complex quantum states for intriguing applications beyond high-efficiency, organic solar cells.
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Affiliation(s)
- Hyungjun Kim
- Department of Chemistry, Incheon National University, Incheon 22012, Republic of Korea.
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87
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Reddy SR, Coto PB, Thoss M. Theoretical study of intramolecular singlet fission in xanthene-bonded pentacene dimers. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.07.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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88
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Tao Y, Chen R, Li H, Yuan J, Wan Y, Jiang H, Chen C, Si Y, Zheng C, Yang B, Xing G, Huang W. Resonance-Activated Spin-Flipping for Efficient Organic Ultralong Room-Temperature Phosphorescence. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1803856. [PMID: 30260515 DOI: 10.1002/adma.201803856] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/03/2018] [Indexed: 06/08/2023]
Abstract
Triplet-excited-state-involved photonic and electronic properties have attracted tremendous attention for next-generation technologies. To populate triplet states, facile intersystem crossing (ISC) for efficient exciton spin-flipping is crucial, but it remains challenging in organic molecules free of heavy atoms. Here, a new strategy is proposed to enhance the ISC of purely organic optoelectronic molecules using heteroatom-mediated resonance structures capable of promoting spin-flipping at large singlet-triplet splitting energies with the aid of the fluctuation of the state energy and n-orbital component upon self-adaptive resonance variation. Combined experimental and theoretical investigations confirm the key contributions of the resonance variation to the profoundly promoted spin-flipping with ISC rate up to ≈107 s-1 in the rationally designed NPX (X = O or S) resonance molecules. Importantly, efficient organic ultralong room-temperature phosphorescence (OURTP) with simultaneously elongated lifetime and improved efficiency results overcoming the intrinsic competition between the OURTP lifetime and efficiency. With the spectacular resonance-activated OURTP molecules, time-resolved and color-coded quick response code devices with multiple information encryptions are realized, demonstrating the fundamental significance of this approach in boosting ISC dynamically for advanced optoelectronic applications.
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Affiliation(s)
- Ye Tao
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), 30 South Puzhu Road, Nanjing, 211816, China
| | - Runfeng Chen
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - Huanhuan Li
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - Jie Yuan
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - Yifang Wan
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - He Jiang
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - Cailin Chen
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - Yubing Si
- Henan Provincial Key-Laboratory of Nano-Composite and Applications, Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan, 450006, China
| | - Chao Zheng
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - Baocheng Yang
- Henan Provincial Key-Laboratory of Nano-Composite and Applications, Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan, 450006, China
| | - Guichuan Xing
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), 30 South Puzhu Road, Nanjing, 211816, China
| | - Wei Huang
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), 30 South Puzhu Road, Nanjing, 211816, China
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89
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Sakai H, Inaya R, Tkachenko NV, Hasobe T. High‐Yield Generation of Triplet Excited States by an Efficient Sequential Photoinduced Process from Energy Transfer to Singlet Fission in Pentacene‐Modified CdSe/ZnS Quantum Dots. Chemistry 2018; 24:17062-17071. [DOI: 10.1002/chem.201803257] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Hayato Sakai
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
| | - Ryutaro Inaya
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
| | - Nikolai V Tkachenko
- Laboratory of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, 33101, Tampere, Finland
| | - Taku Hasobe
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
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90
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Datko BD, Livshits MY, Zhang Z, Portlock D, Qin Y, Rack JJ, Grey JK. Unravelling the enigma of ultrafast excited state relaxation in non-emissive aggregating conjugated polymers. Phys Chem Chem Phys 2018; 20:22159-22167. [PMID: 30116824 DOI: 10.1039/c8cp04061c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate a class of non-emissive conjugated polymers with very short excited state lifetimes believed to undergo singlet fission and relaxation to mid-gap forbidden excited states. Poly(3-decylthieneylenvinylene) (P3DTV) and its heavy atom analog, poly(3-decylseleneylenvinylene) (P3DSV), are strongly aggregating conjugated polymers that experience large excited state displacements along multiple vibrational modes. We demonstrate this Franck-Condon vibrational activity effectively disperses excitation energy into multiple non-radiative channels that can be explained using a simple, two-state potential energy surface model. Resonance Raman spectroscopy is sensitive to early Franck-Condon vibrational activity and we observe rich harmonic progressions involving multiple high frequency CC backbone symmetric stretching motions (∼1000-1600 cm-1) in both systems reflecting mode-specific excited state geometrical displacements. Transient absorption spectra confirm that efficient non-radiative processes dominate excited state relaxation dynamics which are confined to π-stacked aggregated chains. Surprisingly, we found little influence of the heteroatom consistent with efficient vibrational energy dissipation. Our results highlight the importance of aggregation and multi-dimensional Franck-Condon vibrational dynamics on the ability to harvest excitons, which are not usually considered in materials design and optimization schemes.
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Affiliation(s)
- Benjamin D Datko
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131, USA.
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91
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Hu J, Xu K, Shen L, Wu Q, He G, Wang JY, Pei J, Xia J, Sfeir MY. New insights into the design of conjugated polymers for intramolecular singlet fission. Nat Commun 2018; 9:2999. [PMID: 30065295 PMCID: PMC6068183 DOI: 10.1038/s41467-018-05389-w] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 06/28/2018] [Indexed: 11/09/2022] Open
Abstract
Singlet fission (SF), a multiple exciton generation process that generates two triplet excitons after the absorption of one photon, can potentially enable more efficient solar cell designs by harvesting energy normally lost as heat. While low-bandgap conjugated polymers are highly promising candidates for efficient SF-based solar cells, few polymer materials capable of SF have been reported because the SF process in polymer chains is poorly understood. Using transient spectroscopy, we demonstrate a new, highly efficient (triplet yield of 160-200%) isoindigo-based donor-acceptor polymer and show that the triplet pairs are directly emissive and exhibit a time-dependent energy evolution. Importantly, aggregation in poor solvents and in films significantly lowers the singlet energy, suppressing triplet formation because the energy conservation criterion is no longer met. These results suggest a new design rule for developing intramolecular SF capable low-bandgap conjugated polymers, whereby inter-chain interactions must be carefully engineered.
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Affiliation(s)
- Jiahua Hu
- School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 430070, Wuhan, China
| | - Ke Xu
- School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 430070, Wuhan, China
| | - Lei Shen
- School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 430070, Wuhan, China
| | - Qin Wu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Guiying He
- School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 430070, Wuhan, China
| | - Jie-Yu Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Key Laboratory of Polymer Chemistry and Physics of Ministry of Education; Center of Soft Matter Science and Engineering; College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jian Pei
- Beijing National Laboratory for Molecular Sciences (BNLMS), The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Key Laboratory of Polymer Chemistry and Physics of Ministry of Education; Center of Soft Matter Science and Engineering; College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jianlong Xia
- School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 430070, Wuhan, China.
| | - Matthew Y Sfeir
- School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 430070, Wuhan, China.
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA.
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92
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Nagata R, Nakanotani H, Potscavage WJ, Adachi C. Exploiting Singlet Fission in Organic Light-Emitting Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1801484. [PMID: 29974520 DOI: 10.1002/adma.201801484] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/06/2018] [Indexed: 06/08/2023]
Abstract
Harvesting of both triplets and singlets yields electroluminescence quantum efficiencies of nearly 100% in organic light-emitting diodes (OLEDs), but the production efficiency of excitons that can undergo radiative decay is theoretically limited to 100% of the electron-hole pairs. Here, breaking of this limit by exploiting singlet fission in an OLED is reported. Based on the dependence of electroluminescence intensity on an applied magnetic field, it is confirmed that triplets produced by singlet fission in a rubrene host matrix are emitted as near-infrared (NIR) electroluminescence by erbium(III) tris(8-hydroxyquinoline) (ErQ3 ) after excitonic energy transfer from the "dark" triplet state of rubrene to an "emissive" state of ErQ3 , leading to NIR electroluminescence with an overall exciton production efficiency of 100.8%. This demonstration clearly indicates that the harvesting of triplets produced by singlet fission as electroluminescence is possible even under electrical excitation, leading to an enhancement of the quantum efficiency of the OLEDs. Electroluminescence employing singlet fission provides a route toward developing high-intensity NIR light sources, which are of particular interest for sensing, optical communications, and medical applications.
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Affiliation(s)
- Ryo Nagata
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- JST, ERATO, Adachi Molecular Exciton Engineering Project, c/o Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Hajime Nakanotani
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- JST, ERATO, Adachi Molecular Exciton Engineering Project, c/o Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - William J Potscavage
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- JST, ERATO, Adachi Molecular Exciton Engineering Project, c/o Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- JST, ERATO, Adachi Molecular Exciton Engineering Project, c/o Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
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93
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Zeng T, Mellerup SK, Yang D, Wang X, Wang S, Stamplecoskie K. Identifying (BN) 2-pyrenes as a New Class of Singlet Fission Chromophores: Significance of Azaborine Substitution. J Phys Chem Lett 2018; 9:2919-2927. [PMID: 29763325 DOI: 10.1021/acs.jpclett.8b01226] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Singlet fission converts one photoexcited singlet state to two triplet excited states and raises photoelectric conversion efficiency in photovoltaic devices. However, only a handful of chromophores have been known to undergo this process, which greatly limits the application of singlet fission in photovoltaics. We hereby identify a recently synthesized diazadiborine-pyrene ((BN)2-pyrene) as a singlet fission chromophore. Theoretical calculations indicate that it satisfies the thermodynamics criteria for singlet fission. More importantly, the calculations provide a physical chemistry insight into how the BN substitution makes this happen. Both calculation and transient absorption spectroscopy experiments indicate that the chromophore has a better absorption than pentacene. The convenient synthesis pathway of the (BN)2-pyrene suggests an in situ chromophore generation in photovoltaic devices. Two more (BN)2-pyrene isomers are proposed as singlet fission chromophores. This study sets a step forward in the cross-link of singlet fission and azaborine chemistry.
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Affiliation(s)
- Tao Zeng
- Department of Chemistry , Carleton University , Ottawa , Ontario K1S5B6 , Canada
| | - Soren K Mellerup
- Department of Chemistry , Queen's University , Kingston , Ontario K7L3N6 , Canada
| | - Dengtao Yang
- Department of Chemistry , Queen's University , Kingston , Ontario K7L3N6 , Canada
| | - Xiang Wang
- Department of Chemistry , Queen's University , Kingston , Ontario K7L3N6 , Canada
| | - Suning Wang
- Department of Chemistry , Queen's University , Kingston , Ontario K7L3N6 , Canada
| | - Kevin Stamplecoskie
- Department of Chemistry , Queen's University , Kingston , Ontario K7L3N6 , Canada
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94
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Short-axis substitution approach on ladder-type benzodithiophene-based electron acceptor toward highly efficient organic solar cells. Sci China Chem 2018. [DOI: 10.1007/s11426-018-9275-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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95
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Sanders SN, Sfeir MY. The Elusive Nature of Excited States in Singlet Fission Materials. Chem 2018. [DOI: 10.1016/j.chempr.2018.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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96
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Abstract
Singlet fission is a photophysical reaction in which a singlet excited electronic state splits into two spin-triplet states. Singlet fission was discovered more than 50 years ago, but the interest in this process has gained a lot of momentum in the past decade due to its potential as a way to boost solar cell efficiencies. This review presents and discusses the most recent advances with respect to the theoretical and computational studies on the singlet fission phenomenon. The work revisits important aspects regarding electronic states involved in the process, the evaluation of fission rates and interstate couplings, the study of the excited state dynamics in singlet fission, and the advances in the design and characterization of singlet fission compounds and materials such as molecular dimers, polymers, or extended structures. Finally, the review tries to pinpoint some aspects that need further improvement and proposes future lines of research for theoretical and computational chemists and physicists in order to further push the understanding and applicability of singlet fission.
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Affiliation(s)
- David Casanova
- Kimika Fakultatea , Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC) , P.K. 1072, 20080 Donostia , Euskadi, Spain.,IKERBASQUE, Basque, Foundation for Science , 48013 Bilbao , Euskadi, Spain
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97
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Yamakado T, Takahashi S, Watanabe K, Matsumoto Y, Osuka A, Saito S. Conformational Planarization versus Singlet Fission: Distinct Excited‐State Dynamics of Cyclooctatetraene‐Fused Acene Dimers. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802185] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Takuya Yamakado
- Department of Chemistry Graduate School of Science Kyoto University Sakyo-ku Kyoto 606-8502 Japan
| | - Shota Takahashi
- Department of Chemistry Graduate School of Science Kyoto University Sakyo-ku Kyoto 606-8502 Japan
| | - Kazuya Watanabe
- Department of Chemistry Graduate School of Science Kyoto University Sakyo-ku Kyoto 606-8502 Japan
| | - Yoshiyasu Matsumoto
- Department of Chemistry Graduate School of Science Kyoto University Sakyo-ku Kyoto 606-8502 Japan
| | - Atsuhiro Osuka
- Department of Chemistry Graduate School of Science Kyoto University Sakyo-ku Kyoto 606-8502 Japan
| | - Shohei Saito
- Department of Chemistry Graduate School of Science Kyoto University Sakyo-ku Kyoto 606-8502 Japan
- JST-PRESTO FRONTIER Japan
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98
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Yamakado T, Takahashi S, Watanabe K, Matsumoto Y, Osuka A, Saito S. Conformational Planarization versus Singlet Fission: Distinct Excited-State Dynamics of Cyclooctatetraene-Fused Acene Dimers. Angew Chem Int Ed Engl 2018. [PMID: 29516597 DOI: 10.1002/anie.201802185] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A set of flapping acene dimers fused with an 8π cyclooctatetraene (COT) ring showed distinct excited-state dynamics in solution. While the anthracene dimer showed a fast V-shaped-to-planar conformational change within 10 ps in the lowest excited singlet state, reminding us of extended Baird aromaticity, the tetracene dimer and the pentacene dimer underwent intramolecular singlet fission (SF) in different manners: A fast and reversible SF with a characteristic delayed fluorescence (FL), and a fast and quantitative SF, respectively. Conformational flexibility of the fused COT linkage plays an important role in these ultrafast dynamics, demonstrating the utility of the flapping molecular series as a versatile platform for designing photofunctional systems.
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Affiliation(s)
- Takuya Yamakado
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Shota Takahashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Kazuya Watanabe
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Yoshiyasu Matsumoto
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Atsuhiro Osuka
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Shohei Saito
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.,JST-PRESTO, FRONTIER, Japan
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99
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Hetzer C, Guldi DM, Tykwinski RR. Pentacene Dimers as a Critical Tool for the Investigation of Intramolecular Singlet Fission. Chemistry 2018; 24:8245-8257. [DOI: 10.1002/chem.201705355] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Constantin Hetzer
- Department of Chemistry and Pharmacy; Interdisciplinary Center for Molecular Materials (ICMM); Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU); Nikolaus-Fiebiger-Straße 10 91058 Erlangen Germany
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy; Interdisciplinary Center for Molecular Materials (ICMM); Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU); Egerlandstrasse 3 91058 Erlangen Germany
| | - Rik R. Tykwinski
- Department of Chemistry; University of Alberta; Edmonton Alberta T6G 2G2 Canada
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Ito S, Nagami T, Nakano M. Molecular design for efficient singlet fission. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2018. [DOI: 10.1016/j.jphotochemrev.2018.01.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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