Physical insights into non-fullerene organic photovoltaics

Nature Reviews Physics, Journal Year: 2024, Volume and Issue: 6(6), P. 365 - 381

Published: April 15, 2024

Language: Английский

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Efficient Near-Infrared Luminescence of Self-Assembled Platinum(II) Complexes: From Fundamentals to Applications

Accounts of Chemical Research, Journal Year: 2023, Volume and Issue: 56(6), P. 689 - 699

Published: March 8, 2023

ConspectusDesigning bright and efficient near-infrared (NIR) emitters has drawn much attention due to numerous applications ranging from biological imaging, medical therapy, optical communication, night-vision devices. However, polyatomic organic organometallic molecules with energy gaps close the deep red NIR regime are subject dominant nonradiative internal conversion (IC) processes, which drastically reduces emission intensity exciton diffusion length of materials hence hampers optoelectronic performances. To suppress IC rates, we suggested two complementary approaches solve issues: delocalization molecular deuteration. First, efficiently suppresses reorganization through partitioning all aggregated molecules. According theory together effect delocalization, simulated rates gap ΔE = 104 cm-1 decrease by around fold when equals 5 (promoting vibronic frequency ωl 1500 cm-1). Second, deuterations reduce Franck-Condon vibrational overlaps frequencies promoting modes, decreases 1 order magnitude in comparison nondeuterated under cm-1. Although deuteration long been attempted increase intensity, results have mixed. Here, provide a robust derivation demonstrate its validity, especially region.The concepts experimentally verified strategic design synthesis class square-planar Pt(II) complexes, form crystalline aggregates vapor deposited thin films. The packing geometries well characterized grazing angle X-ray diffraction (GIXD), showing domino-like arrangements short ππ separation 3.4-3.7 Å. Upon photoexcitation, such closely packed assemblies exhibit intense maximized 740-970 nm region metal-metal-to-ligand charge transfer (MMLCT) transition unprecedented photoluminescent quantum yield (PLQY) 8-82%. validate existence applied time-resolved step-scan Fourier transform UV-vis spectroscopy probe aggregates, is 5-9 (2.1-4.5 nm) assuming that excitons mainly delocalized along direction stacking. dependence vs verify observed lengths contribute high PLQY complexes. isotope effect, both partially completely deuterated complexes were synthesized. For case 970 emitter, films per-deuterated same peak as one, whereas increases ∼50%. put fundamental studies into practice, light-emitting diodes (OLEDs) fabricated variety emitting layer, outstanding external efficiencies (EQEs) 2-25% remarkable radiances 10-40 W sr-1 m-2 at 740-1002 nm. prominent device performances not only successfully prove our designed concept but also reach new milestone for highly OLED devices.This Account thus summarizes about how boost efficiency an in-depth basis, i.e., design, photophysical characterization, fabrication. may be applicable single system achieve radiance, worth further investigation future.

Language: Английский

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Molecularly Engineered Room-Temperature Phosphorescence for Biomedical Application: From the Visible toward Second Near-Infrared Window

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(24), P. 13966 - 14037

Published: Nov. 22, 2023

Phosphorescence, characterized by luminescent lifetimes significantly longer than that of biological autofluorescence under ambient environment, is great value for biomedical applications. Academic evidence fluorescence imaging indicates virtually all metrics (sensitivity, resolution, and penetration depths) are improved when progressing into wavelength regions, especially the recently reported second near-infrared (NIR-II, 1000–1700 nm) window. Although emission probes does matter, it not clear whether guideline "the wavelength, better effect" still suitable developing phosphorescent probes. For tissue-specific bioimaging, long-lived probes, even if they emit visible phosphorescence, enable accurate visualization large deep tissues. studies dealing with bioimaging tiny architectures or dynamic physiopathological activities, prerequisite rigorous planning long-wavelength being aware cooperative contribution long wavelengths improving spatiotemporal depth, sensitivity bioimaging. In this Review, emerging molecular engineering methods room-temperature phosphorescence discussed through lens photophysical mechanisms. We highlight roles from to NIR-II windows toward bioapplications. To appreciate such advances, challenges prospects in rapidly growing described.

Language: Английский

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Recent advances in highly-efficient near infrared OLED emitters

Materials Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 8(7), P. 1731 - 1766

Published: Jan. 1, 2024

This work describes recent developments in near-infrared (NIR) organic light-emitting diode (OLED) emitters. We discuss applications of NIR OLEDs as well various groups highly luminescent materials used the OLED emissive layer.

Language: Английский

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Platinum complexes with aggregation-induced emission

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(11), P. 5366 - 5393

Published: Jan. 1, 2024

Recent advances in the design of AIE platinum complexes: structural regulation strategies, mechanisms, and applications.

Language: Английский

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Decoupling excitons from high-frequency vibrations in organic molecules

Nature, Journal Year: 2024, Volume and Issue: 629(8011), P. 355 - 362

Published: May 8, 2024

Abstract The coupling of excitons in π-conjugated molecules to high-frequency vibrational modes, particularly carbon–carbon stretch modes (1,000–1,600 cm −1 ) has been thought be unavoidable 1,2 . These accelerate non-radiative losses and limit the performance light-emitting diodes, fluorescent biomarkers photovoltaic devices. Here, by combining broadband impulsive spectroscopy, first-principles modelling synthetic chemistry, we explore exciton–vibration a range molecules. We uncover two design rules that decouple from vibrations. First, when exciton wavefunction substantial charge-transfer character with spatially disjoint electron hole densities, find can localized either donor or acceptor moiety, so they do not significantly perturb energy its spatial distribution. Second, it is possible select materials such participating molecular orbitals have symmetry-imposed non-bonding are, thus, decoupled modulate π-bond order. exemplify both these creating series spin radical systems very efficient near-infrared emission (680–800 nm) excitons. show only below 250 , frequencies are too low allow fast decay. This enables decay rates suppressed nearly orders magnitude comparison similar bandgaps. Our results due need fundamental property systems.

Language: Английский

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Effects of Deuterium Isotopes on Pt(II) Complexes and Their Impact on Organic NIR Emitters

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(10)

Published: Jan. 17, 2024

Insight into effect of deuterium isotopes on organic near-IR (NIR) emitters was explored by the use self-assembled Pt(II) complexes H-3-f and HPh-3-f, their deuterated analogues D-3-f DPh-3-f, respectively (Scheme 2). In vacuum deposited thin film, albeit having nearly identical emission spectral feature maximized at ~810 nm, exhibit remarkable difference in photoluminescence quantum yield (PLQY) 29 % 50 %, respectively. Distinction PLQY is also observed for HPh-3-f (800 %) DPh-3-f (798 67 %). We then elucidated theoretical differences impact near-infrared luminescence between small molecules upon deuteration. The results establish a general guideline deuteration NIR efficiency. From perspective practical application, OLEDs based attain EQE

Language: Английский

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Excellent Persistent Near‐Infrared Room Temperature Phosphorescence from Highly Efficient Host–Guest Systems

Advanced Science, Journal Year: 2024, Volume and Issue: 11(28)

Published: May 17, 2024

Abstract Organic near‐infrared (NIR) room temperature phosphorescence (RTP) materials become a hot topic in bioimaging and biosensing for the large penetration depth high signal‐to‐background ratio (SBR). However, it is challenging to achieve persistent NIR severe nonradiative transitions by energy‐gap law. Herein, universal system with RTP built visible (host) (guest) materials, which can efficiently suppress rigid environment of crystalline host good matching, further promote emission additional resonance energy transfer (≈100%) between them. The ten‐folds enhancement lifetimes, compared those guest luminogens, be achieved modulation aggregated structures host–guest systems. This work provides convenient way largely prolong lifetimes various promoting their application afterglow imaging deeper higher SBRs.

Language: Английский

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Design of Near-Infrared-Triggered Metallo-Photosensitizers via a Self-Assembly-Induced Vibronic Decoupling Strategy

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(21), P. 11633 - 11642

Published: May 19, 2023

Development of highly efficient near-infrared (NIR)-excited photosensitizers is hampered by the fast nonradiative vibrational relaxation process regulated energy gap law. Here, from fundamental perspective we propose that intermolecular coupling well-designed has potential to facilitate exciton delocalization and hence reduce exciton-vibration coupling, thereby boosting their phototherapeutic efficacy via inhibition pathway. Such conceived NIR-excited metallo-photosensitizers (IrHA1 IrHA2) were prepared studied for experimental validation. The resulting iridium complexes exhibited a little singlet oxygen (1O2) production in monomeric state, but produced substantially enhanced 1O2 generation efficiency benefiting decoupling self-assembly state. Particularly, IrHA2 exhibits an unprecedented high quantum yield 54.9% (FDA-approved NIR dye indocyanine green: ΦΔ = 0.2%) under 808 nm laser irradiation with negligible heat generation, probably attributed suppression vibronic couplings stretching mode acceptor ligand. In phototherapy, IrHA2-NPs biocompatibility low dark toxicity can induce substantial tumor regression 92.9% volume reduction vivo. This self-assembly-induced strategy would offer effective approach design high-performance photosensitizers.

Language: Английский

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Enhancing operational stability of OLEDs based on subatomic modified thermally activated delayed fluorescence compounds

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Oct. 14, 2023

The realization of operationally stable blue organic light-emitting diodes is a challenging issue across the field. While device optimization has been focus to effectively prolong lifetime, strategies based on molecular engineering chemical structures, particularly at subatomic level, remains little. Herein, we explore effect targeted deuteration donor and/or acceptor units thermally activated delayed fluorescence emitters and investigate structure-property relationship between intrinsic stability, isotopic effect, operational stability. We show that unit critical enhance photostability compounds hence lifetime in addition units, which commonly neglected due limited availability synthetic complexity deuterated acceptors. Based these analogues, observe gradual increase stability achieve long-lifetime time 90% initial luminance 23.4 h 1000 cd m-2 for fluorescence-sensitized diodes. anticipate our strategic approach provides insights demonstrates importance structural modification materials level towards prolonging

Language: Английский

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