scholarly journals Identification of a Bridge-specific Intramolecular Exciton Dissociation Pathway in Donor-π-acceptor Alternating Conjugated Polymers 

2020 ◽  
Author(s):  
Zhaoyong Jiao ◽  
Tingting Jiang ◽  
Zhongpo Zhou ◽  
Chaochao Qin ◽  
Jinyou Long ◽  
...  
Keyword(s):  
Steady State ◽  
Conjugated Polymers ◽  
Organic Solar Cells ◽  
Transient Absorption ◽  
Dissociation Pathway ◽  
Relaxation Dynamics ◽  
Exciton Dissociation ◽  
Time Resolved ◽  
High Efficient ◽  
Conversion Efficiencies

Abstract Intramolecular exciton dissociation is critical for high efficient mobile charge carrier generations in organic solar cells. Yet despite much attention, the effects of π bridges on exciton dissociation dynamics in Donor-π-Acceptor (D-π-A) alternating conjugated polymers remain still unclear. Here, using a combination of femtosecond time-resolved transient absorption (TA) spectroscopy and steady-state spectroscopy, we track ultrafast intramolecular exciton relaxation dynamics in three D-π-A alternating conjugated polymers which were synthesized by Qin's group and named HSD-A, HSD-B, HSD-C. It is found that the addition of thiophene unit as π bridges will lead to the red shift of steady-state absorption spectrum. Importantly, we reveal the existence of a new intramolecular exciton dissociation pathway mediated by a bridge-specific charge transfer (CT') state with the TA fingerprint peak at 1200 nm in π-bridged HSD-B and HSD-C. This CT' state results in higher electron capture rates for HSD-B and HSD-C as compared to HSD-A. Depending on the proportion of CT' state and nongeminate recombination are important step for the understanding of high power conversion efficiencies in HSD-B than in HSD-C. We propose that this bridge-specific exciton dissociation pathway plays an important role in ultrafast intramolecular exciton dissociation of organic photovoltaic material D-π-A alternating conjugated polymers.

scholarly journals Identification of a bridge-specific intramolecular exciton dissociation pathway in donor–π–acceptor alternating conjugated polymers

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zhaoyong Jiao ◽  
Tingting Jiang ◽  
Zhongpo Zhou ◽  
Chaochao Qin ◽  
Jinyou Long ◽  
...  
Keyword(s):  
Steady State ◽  
Conjugated Polymers ◽  
Organic Solar Cells ◽  
Transient Absorption ◽  
Dissociation Pathway ◽  
Relaxation Dynamics ◽  
Exciton Dissociation ◽  
Time Resolved ◽  
High Efficient ◽  
Conversion Efficiencies

AbstractIntramolecular exciton dissociation is critical for high efficient mobile charge carrier generations in organic solar cells. Yet despite much attention, the effects of π bridges on exciton dissociation dynamics in donor–π–acceptor (D-π-A) alternating conjugated polymers remain still unclear. Here, using a combination of femtosecond time-resolved transient absorption (TA) spectroscopy and steady-state spectroscopy, we track ultrafast intramolecular exciton relaxation dynamics in three D-π-A alternating conjugated polymers which were synthesized by Qin's group and named HSD-A, HSD-B, HSD-C. It is found that the addition of thiophene unit as π bridges will lead to the red shift of steady-state absorption spectrum. Importantly, we reveal the existence of a new intramolecular exciton dissociation pathway mediated by a bridge-specific charge transfer (CT′) state with the TA fingerprint peak at 1200 nm in π-bridged HSD-B and HSD-C. This CT′ state results in higher electron capture rates for HSD-B and HSD-C as compared to HSD-A. Depending on the proportion of CT′ state and nongeminate recombination are important step for the understanding of high power conversion efficiencies in HSD-B than in HSD-C. We propose that this bridge-specific exciton dissociation pathway plays an important role in ultrafast intramolecular exciton dissociation of organic photovoltaic material D-π-A alternating conjugated polymers.

Incorporating Semiflexible Linkers into Double-Cable Conjugated Polymers via Click Reaction

2021 ◽  
Author(s):  
Zhaofan Yang ◽  
Shijie Liang ◽  
Baiqiao Liu ◽  
Jing Wang ◽  
Fan Yang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Conjugated Polymers ◽  
Organic Solar Cells ◽  
Click Reaction ◽  
Bulk Heterojunction ◽  
Power Conversion ◽  
Single Component ◽  
Photovoltaic Technology ◽  
Conversion Efficiencies ◽  
Excellent Stability

Single-component organic solar cells (SCOSCs) have been recognized as the promising photovoltaic technology due to the excellent stability, but their power conversion efficiencies (PCEs) are far lagging their bulk-heterojunction counterparts....

EMI Series Mechanistic Investigation of a Visible Light Mediated Dehalogenation/Cyclisation Reaction using Iron(III), Iridium(III) and Ruthenium(II) Photosensitizers

2021 ◽  
Author(s):  
Akin Aydogan ◽  
Rachel Bangle ◽  
Simon De Kreijger ◽  
John Dickenson ◽  
Michael L Singleton ◽  
...  
Keyword(s):  
Steady State ◽  
Visible Light ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Time Resolved ◽  
Femtosecond Transient Absorption ◽  
Mechanistic Investigation ◽  
Femtosecond Transient Absorption Spectroscopy ◽  
Visible Light Driven ◽  
Time Resolved Infrared Spectroscopy

The mechanism of a visible light-driven dehalogenation/cyclization reaction was investigated using ruthenium(II), iridium(III) and iron(III) photosensitizers by means of steady-state photoluminescence, time-resolved infrared spectroscopy, and nanosecond/femtosecond transient absorption spectroscopy. The...

Photoinduced electron transfer (PET) versus excimer formation in supramolecular p/n-heterojunctions of perylene bisimide dyes and implications for organic photovoltaics

2015 ◽  
Vol 185 ◽  
pp. 507-527 ◽  
Author(s):  
Agnieszka Nowak-Król ◽  
Benjamin Fimmel ◽  
Minjung Son ◽  
Dongho Kim ◽  
Frank Würthner
Keyword(s):  
Electron Transfer ◽  
Organic Solar Cells ◽  
Photoinduced Electron Transfer ◽  
Transient Absorption ◽  
Model Systems ◽  
Transient Absorption Spectroscopy ◽  
Time Resolved ◽  
Perylene Bisimide ◽  
Excimer Formation ◽  
Molecular Semiconductor

Foldamer systems comprised of two perylene bisimide (PBI) dyes attached to the conjugated backbones of 1,2-bis(phenylethynyl)benzene and phenylethynyl-bis(phenylene)indane, respectively, were synthesized and investigated with regard to their solvent-dependent properties. UV/Vis absorption and steady-state fluorescence spectra show that both foldamers exist predominantly in a folded H-aggregated state consisting of π–π-stacked PBIs in THF and in more random conformations with weaker excitonic coupling between the PBIs in chloroform. Time-resolved fluorescence spectroscopy and transient absorption spectroscopy reveal entirely different relaxation pathways for the photoexcited molecules in the given solvents, i.e. photoinduced electron transfer leading to charge separated states for the open conformations (in chloroform) and relaxation into excimer states with red-shifted emission for the stacked conformations (in THF). Supported by redox data from cyclic voltammetry and Rehm–Weller analysis we could relate the processes occurring in these solution-phase model systems to the elementary processes in organic solar cells. Accordingly, only if relaxation pathways such as excimer formation are strictly avoided in molecular semiconductor materials, excitons may diffuse over larger distances to the heterojunction interface and produce photocurrent via the formation of electron/hole pairs by photoinduced electron transfer.

scholarly journals Time-Resolved Spectroscopy of Polymethine J-Aggregates

1991 ◽  
Vol 11 (1) ◽  
pp. 1-12 ◽  
Author(s):  
K.-H. Feller ◽  
R. Gadonas ◽  
V. Krasauskas ◽  
V. Fidler ◽  
S. Vajda
Keyword(s):  
Steady State ◽  
Transient Absorption ◽  
Decay Kinetics ◽  
Time Resolved ◽  
Absorption And Fluorescence Spectroscopy ◽  
Transient Absorption Spectra ◽  
J Aggregates ◽  
Exciton Annihilation ◽  
Deactivation Process ◽  
Aggregate Structures

The deactivation process of J-aggregates of DDEOCI (3,3'-diethyl-5,5'-diphenyl-9-ethyl-oxacarbocyanine iodide) was investigated by means of steady-state and time-resolved absorption and fluorescence spectroscopy. The decay kinetics as well as the transient absorption spectra have been analyzed including different aggregate structures and exciton-exciton annihilation.

scholarly journals Dynamic exciton localisation in a pyrene–BODIPY–pyrene dye conjugate

2019 ◽  
Vol 21 (18) ◽  
pp. 9013-9025 ◽  
Author(s):  
Nina Auerhammer ◽  
Alexander Schulz ◽  
Alexander Schmiedel ◽  
Marco Holzapfel ◽  
Joscha Hoche ◽  
...  
Keyword(s):  
Steady State ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Time Resolved ◽  
Surface Hopping

The photophysics of a molecular triad consisting of a BODIPY dye and two pyrene chromophores attached in 2-position are investigated by steady state and fs-time resolved transient absorption spectroscopy as well as by field induced surface hopping (FISH) simulations.

Catching metallic nitride endohedral fullerenes in organic and aqueous media

2016 ◽  
Vol 20 (08n11) ◽  
pp. 1025-1033 ◽  
Author(s):  
Volker Strauss ◽  
Shankara Gayathri Radhakrishnan ◽  
Jenny Malig ◽  
Norbert Jux ◽  
Dirk M. Guldi
Keyword(s):  
Steady State ◽  
Absorption Spectroscopy ◽  
Charge Separation ◽  
Transient Absorption ◽  
Aqueous Media ◽  
Transient Absorption Spectroscopy ◽  
Time Resolved ◽  
Endohedral Fullerenes ◽  
Multi Wavelength ◽  
Metallic Nitride

Two bis-tetraphenylporphyrin tweezers-like conjugates bearing different linkers have been characterized by means of electrochemical and photophysical methods. The thrust of this work was the complexation of these bis-porphyrins with C[Formula: see text] and metallic nitride endohedral fullerenes (MNEF) like Sc3N@C[Formula: see text] in organic and in aqueus media — studied by a combination of steady-state and time-resolved spectroscopies. In the context of charge separation evidence for the formation of the 1a[Formula: see text]-Sc3N@C[Formula: see text] and 1c[Formula: see text]-Sc3N@C[Formula: see text] charge separated states in organic and aqueous media, respectively, came from transient absorption spectroscopy. Multi-wavelength analyses afforded charge separated state lifetimes of around 400 ps.

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