Triplet Quantum Research Articles

Multifunctional broadband visible-light absorbing selenophene modified bodipy photosensitizers

Large π-conjugated organic systems with effective photosensitization are highly desirable for many photochemical applications. Herein, a series of π-conjugated selenophene-substituted boron dipyrromethene (known as bodipy) dyes (MB-Se, 2B–Se, MB-Se-2Br) were prepared by appending selenophene electron-donor to the core of bodipy acceptors via alkynyl bridge and their excited state properties were investigated. Optical spectroscopy revealed that although these three selenophene-substituted bodipy dyes have nearly identical molecular profiles, their photophysical properties and excited state dynamics are drastically different. Higher triplet quantum efficiency (ΦΔ = 82%) was observed for MB-Se, derivative in which α,β-positions of bodipy decorated with methyl substituents, compared to another dye 2B–Se, which showed inefficient triplet population (ΦΔ = 25%). Employing steady-state absorption and emission spectroscopies, we demonstrated that the designed selenophene-substituted bodipy dyes has excellent J-aggregation capabilities. Notably, the J-aggregates of selenophene-substituted bodipy dyes display NIR emission. The potential of devised selenophene-substituted bodipy dyes in triplet fusion upconversion was also demonstrated; a blue upconverted emission was realized upon irradiating the mixture of bodipy dyes and TIPS-AC acceptor with 589 nm CW-laser. The selenophene-substituted bodipy dyes were also confirmed to be a potent photodynamic therapeutic reagent; with an IC50 value of 0.76 μM, nearly 6 times lower than that of the iodide-appended bodipy photosensitizer (BDP-2I, 6.0 μM). This study hopes to provide valuable guidelines for the future development of multipurpose triplet photosensitizers.

Sensitized Singlet Fission in Rigidly Linked Axial and Peripheral Pentacene-Subphthalocyanine Conjugates

The goal of harnessing the theoretical potential of singlet fission (SF), a process in which one singlet excited state is split into two triplet excited states, has become a central challenge in solar energy research. Covalently linked dimers provide crucial models for understanding the role of chromophore arrangement and coupling in SF. Sensitizers can be integrated into these systems to expand the absorption bandwidth through which SF can be accessed. Here, we define the role of the sensitizer-chromophore geometry in a sensitized SF model system. To this end, two conjugates have been synthesized consisting of a pentacene dimer (SF motif) connected via a rigid alkynyl bridge to a subphthalocyanine (the sensitizer motif) in either an axial or a peripheral arrangement. Steady-state and time-resolved photophysical measurements are used to confirm that both conjugates operate as per design, displaying near unity energy transfer efficiencies and high triplet quantum yields from SF. Decisively, energy transfer between the subphthalocyanine and pentacene dimer occurs ca. 26 times faster in the peripheral conjugate, even though the two chromophores are ca. 3 Å farther apart than in the axial conjugate. Following a theoretical evaluation of the dipolar coupling, Vdip2, and the orientation factor, κ2, of both the axial (Vdip2 = 140 cm-2; κ2 = 0.08) and the peripheral (Vdip2 = 724 cm-2; κ2 = 1.46) arrangements, we establish that this rate acceleration is due to a more favorable (nearly co-planar) relative orientation of the transition dipole moments of the subphthalocyanine and pentacenes in the peripheral constellation.

Move Aside Pentacene: Diazapentacene-Doped para-Terphenyl, a Zero-Field Room-Temperature Maser with Strong Coupling for Cavity Quantum Electrodynamics.

Masers can deliver ultralow-noise amplification of microwave signals in medical imaging and deep-space communication, with recent research being rekindled through the discovery of gain media operating at room-temperature, eschewing bulky cryogenics that hindered their use. This work shows the discovery of 6,13-diazapentacene doped in para-terphenyl (DAP:PTP) as a maser gain medium that can operate at room-temperature, without an external magnetic field. With a maser output power of -10 dBm, it is on par with pentacene-doped para-terphenyl in masing power, while possessing compelling advantages such as faster amplification startup times, being pumped by longer wavelength light at 620 nm and greater chemical stability from nitrogen groups. Furthermore, the maser bursts from DAP:PTP allow one to reach the strong coupling regime for cavity quantum electrodynamics, with a highcooperativity of 182. The optical and microwave spin dynamics of DAP:PTP are studied in order to evaluate its capabilities as a maser gain medium, where it features fast intersystem crossing and an advantageously higher triplet quantum yield. The results pave the way for the future discovery of similar maser materials and help designate them as promising candidates for quantum sensors, optoelectronic devices and the study of cavity quantum electrodynamic effects atroom-temperature.

Unveiling the intersystem crossing dynamics in N-annulated perylene bisimides.

The efficient population of the triplet excited states in heavy metal-free organic chromophores has been one of the long-standing research problems to molecular photochemists. The negligible spin-orbit coupling matrix elements in the purely organic chromophores and the large singlet-triplet energy gap (ΔES-T) pose a hurdle for ultrafast intersystem crossing (ISC). Herein we report the unprecedented population of triplet manifold in a series of nitrogen-annulated perylene bisimide chromophores (NPBI and Br-NPBI). NPBI is found to have a moderate fluorescence quantum yield (Φf = 68 ± 5%), whereas Br-NPBI showcased a low fluorescence quantum yield (Φf = 2.0 ± 0.6%) in toluene. The femtosecond transient absorption measurements of Br-NPBI revealed ultrafast ISC (kISC = 1.97 × 1010 s-1) from the initially populated singlet excited state to the long-lived triplet excited states. The triplet quantum yields (ΦT = 95.2 ± 4.6% for Br-NPBI, ΦT = 18.7 ± 2.3% for NPBI) calculated from nanosecond transient absorption spectroscopy measurements showed the enhancement in triplet population upon bromine substitution. The quantum chemical calculations revealed the explicit role of nitrogen annulation in tuning the excited state energy levels to favor the ISC. The near degeneracy between the singlet and triplet excited states observed in NPBI and Br-NPBI (ΔES-T = -0.01 eV for NPBI, ΔES-T = 0.03 eV for Br-NPBI) facilitates the spin flipping in the molecules. Nitrogen annulation emerges as a design strategy to open up the ISC pathway and the rate of which can be further enhanced by the substitution of a heavier element.

Topological superconductivity from doping a triplet quantum spin liquid in a flat-band system

We explore superconductivity in strongly interacting electrons on a decorated honeycomb lattice (DHL). An easy-plane ferromagnetic interaction arises from spin-orbit coupling in the Mott insulating phase, which favors a triplet resonance valence bond spin liquid state. Hole doping leads to partial occupation of a flat band and to triplet superconductivity. The order parameter is highly sensitive to the doping level and the interaction parameters, with $p+ip$, $f$ and $p+f$ superconductivity found, as the flat band leads to instabilities in multiple channels. Typically, first order transitions separate different superconducting phases, but a second order transition separates two time reversal symmetry breaking $p+ip$ phases with different Chern numbers ($\nu=0$ and 1). The Majorana edge modes in the topological ($\nu=1$) superconductor are almost localized due to the strong electronic correlations in a system with a flat band at the Fermi level. This suggests that these modes could be useful for topological quantum computing. The `hybrid' $p+f$ state does not require two phase transitions as temperature is lowered. This is because the symmetry of the model is lowered in the $p$-wave phase, allowing arbitrary admixtures of $f$-wave basis functions as overtones. We show that the multiple sites per unit cell of the DHL, and hence multiple bands near the Fermi energy, lead to very different nodal structures in real and reciprocal space. We emphasize that this should be a generic feature of multi-site/multi-band superconductors.

Tailoring intersystem crossing of perylenediimide through chalcogen-substitution at bay-position: A theoretical perspective.

Molecular-scale design strategies for promoting intersystem crossing (ISC) in small organic molecules are ubiquitous in developing efficient metal-free triplet photosensitizers with high triplet quantum yield (ΦT). Air-stable and highly fluorescent perylenediimide (PDI) in its pristine form displays very small ISC compared to the fluorescence due to the large singlet-triplet gap (ΔES-T) and negligibly small spin-orbit coupling (SOC) between the lowest singlet (S1) and triplet state (T1). However, its ΦT can be tuned by different chemical and mechanical means that are capable of either directly lowering the ΔES-T and increasing SOC or introducing intermediate low-lying triplet states (Tn, n = 2, 3, …) between S1 and T1. To this end, herein, a few chalcogen (X = O, S, Se) bay-substituted PDIs (PDI-X2) are computationally modeled aiming at introducing geometrical-strain at the PDI core and also mixing nπ* orbital character to ππ* in the lowest singlet and triplet excited states, which altogether may reduce ΔES-T and also improve the SOC. Our quantum-chemical calculations based on optimally tuned range-separated hybrid reveal the presence of intermediate triplet states (Tn, n = 2, 3) in between S1 and T1 for all three PDI-X2 studied in dichloromethane. More importantly, PDI-X2 shows a significantly improved ISC rate than the pristine PDI due to the combined effects stemming from the smaller ΔES-T and the larger SOC. The calculated ISC rates follow the order as PDI-O2 < PDI-S2 < PDI-Se2. These research findings will be helpful in designing PDI based triplet photosensitizers for biomedical, sensing, and photonic applications.

The effect of PAMAM dendrimers on the excited states of little-explored xanthene dyes. In search of eco-friendly photoinitiating systems

A complete photophysical and photochemical study on the partially halogenated xanthene dyes 2’,7’-dichlorofluorescein; 4, 5, 6, 7- tetrachlorofluorescein; 4’, 5’-dibromofluorescein and 4’, 5’-diiodofluorescein was carried out in aqueous solution. The effect of three PAMAM dendrimers of low generations (G0, G1 and G3) on their excited states was also evaluated. Absorption and fluorescence measurements showed that although the ground and singlet-excited states of the dyes interact weakly with the dendrimers, the binding constants obtained correlated with dendrimer size. The triplet-excited states of the dyes were studied by laser flash photolysis including those for the chlorinated fluoresceins; which, to the best of our knowledge, had not been characterized until now. Iodo- and bromo-fluoresceins showed high triplet quantum yields, whereas chlorinated ones showed values in the order of 0.10, indicating that, although low, the intersystem crossing is not a negligible process. Efficient electron transfer reactions were observed between amino moieties of PAMAM and the triplet states of the dyes. The triplet quenching rate constants also correlated with dendrimer size and the semi-reduced species of the dyes were characterized by their transient spectra. Radical formation efficiencies similar to those obtained with a typical tertiary amine were estimated, so the present results suggest that these dye/dendrimer couples might be promising as photoinitiating systems for polymerizations with low ecological impact.

Improved Hypericin solubility via β-cyclodextrin complexation: Photochemical and theoretical study for PDT applications

Hypericin (HY) is a lipophilic photosensitizer (PS) extensively employed for photodynamic therapy (PDT), presenting high absorption in the visible region, chemical and photostability, as well as a good triplet quantum yield. Supramolecular complexation of photosensitizers into cyclodextrins (CD) is promising to improve their poor solubility, compromising their bioavailability and upcoming applications in PDT. This research produced an inclusion complex between HY and β-CD through the co-solvent method. HY became soluble after inclusion into β-CD cavities, besides retaining its fluorescent and singlet oxygen quantum yields (ϕf =0.115 and ϕΔ= 0.23, respectively), which are essential parameters for PDT uses and are not reported in the literature. By the theoretical analysis, since ΔG < 0, it was easy to conclude that HY inclusion into β-CD is a spontaneous process. Additionally, the complexes presented no changes in excited states after complexation. β-CDHY was 27% more phototoxic than free HY when tested in MCF7 cells using 3 J cm−2 of irradiation, indicating a better cell uptake of HY. These outcomes suggest that the inclusion complex of HY into β-CD has the potential for use in PDT.

Integrating Subphthalocyanines and Porphyrazines into Singlet Fission

The synergy of panchromatic absorption throughout most of the visible range of the solar spectrum and intramolecular singlet fission (i-SF) has been realized in a series of conjugates featuring different light harvesting subphthalocyanines (SubPc) / porphyrazines (Pz) and an energy accepting pentacene dimer (Pnc2). At the focal point was a modular approach, which was based on decorating the SubPc / Pz core with different peripheral substituents to tailor and fine-tune their optical properties. Transient absorption measurements assisted in corroborating that the SubPcs / Pzs act as energy-transfer antennas by means of unidirectional and quantitative intramolecular Förster resonance energy transfer (FRET) to the Pnc2, where an i-SF affords triplet quantum yields reaching unity.

Ultrafast Intersystem Crossing Dynamics of 6-Selenoguanine in Water.

Rationalizing the photochemistry of nucleobases where an oxygen is replaced by a heavier atom is essential for applications that exploit near-unity triplet quantum yields. Herein, we report on the ultrafast excited-state deactivation mechanism of 6-selenoguanine (6SeGua) in water by combining nonadiabatic trajectory surface-hopping dynamics with an electrostatic embedding quantum mechanics/molecular mechanics (QM/MM) scheme. We find that the predominant relaxation mechanism after irradiation starts on the bright singlet S2 state that converts internally to the dark S1 state, from which the population is transferred to the triplet T2 state via intersystem crossing and finally to the lowest T1 state. This S2 → S1 → T2 → T1 deactivation pathway is similar to that observed for the lighter 6-thioguanine (6tGua) analogue, but counterintuitively, the T1 lifetime of the heavier 6SeGua is shorter than that of 6tGua. This fact is explained by the smaller activation barrier to reach the T1/S0 crossing point and the larger spin–orbit couplings of 6SeGua compared to 6tGua. From the dynamical simulations, we also calculate transient absorption spectra (TAS), which provide two time constants (τ1 = 131 fs and τ2 = 191 fs) that are in excellent agreement with the experimentally reported value (τexp = 130 ± 50 fs) (Farrel et al. J. Am. Chem. Soc.2018, 140, 11214). Intersystem crossing itself is calculated to occur with a time scale of 452 ± 38 fs, highlighting that the TAS is the result of a complex average of signals coming from different nonradiative processes and not intersystem crossing alone.

Revisiting the Dynamics of Triplet Formation in Anthraquinones.

Triplet formation pathways in 9,10-anthraquinone (AQ) and its hydroxy derivative, 1-hydroxyanthraquinone (HAQ), are studied theoretically. Dynamics simulations on the model singlet-triplet potential energy surfaces within the linear vibronic coupling framework are performed to elucidate possible internal conversion (IC) and intersystem crossing (ISC) pathways in these molecules. An ultrafast IC decay from the "bright" S4 to S1 followed by efficient ISC via S1-T4 and S1-T5 pathways fosters a high triplet quantum yield (ΦT = 0.90) in AQ. In HAQ, a new nonradiative channel of "barrierless" excited-state intramolecular proton transfer (ESIPT) opens up and competes with the IC decay to S1 upon photoexcitation to the "bright" S2. Extremely fast ESIPT on S2 reduces the efficiency of triplet formation via possible ISC pathways involving S1 and S2, resulting in a low ΦT (=0.17).

Photodegradation of tetracycline by asymmetrical zinc(II)phthalocyanines conjugated to cobalt tungstate nanoparticles

This work focused on syntheses of novel asymmetrically tetra substituted Zn phthalocyanines (ZnPc) each containing a single carboxyl group, with the other substituents bearing alkynyl (complex 1) and fluorine containing groups (complexes 2 and 3). The complexes were conjugated to cobalt tungstate nanoparticles and employed as efficient photocatalysts for degradation of tetracycline in water. ZnPc complexes and their conjugates showed good photophysical and photochemical properties behaviour with complex 1 giving higher triplet and singlet oxygen quantum yields compared to 2 and 3. Complex 1 showed higher activity towards the photodegradation of tetracycline compared to complexes 2 and 3, with higher kobs and initial rates for the former. The photocatalysis obeyed the Langmuir-Hinshelwood kinetic model.

Empirical DFT Model to Predict Triplet Quantum Yield Through Singlet Oxygen Yields

AbstractTriplet photosensitizers can be used for a variety of applications, including photocatalysis, OLEDs, and photodynamic therapy. Excited triplet states can be quenched by triplet oxygen to make singlet oxygen. Often the singlet oxygen quantum yield (Φ▵) is used as a lower approximation for the triplet yield. Unpredictable effects of even minor structural changes can drastically alter the Φ▵ and complicate the design of new triplet photosensitizers. The most common strategy to increase Φ▵ is to incorporate heavy atoms, promoting the “heavy atom effect”. However, the position and the identity of the heavy atom greatly influences the Φ▵. We have created a predictive model that correlates calculated natural atomic orbital composition of the heavy atom(s) contributing to the frontier molecule orbitals of a photosensitizer with the experimental Φ▵. The model, derived from several fluorescein derivatives, provides a calculated Φ▵ in agreement with the experimental values for a variety of well‐known photosensitizers, including rhodamine dyes, fluorescein derivatives, and octahedral metal complexes.

Photophysics of tetracarboxy-zinc phthalocyanine photosensitizers.

Zinc-tetracarboxy-phthalocyanine (ZnPc(COOH)4) was synthesized by a melting method and basic hydrolysis. A ZnPc(COOH)4/Fe3O4/Ch composite was prepared by immobilization of ZnPc(COOH)4 onto Fe3O4/chitosan nanoparticles by a simple immersion method. The photophysical properties were studied using UV-vis spectrophotometry, fluorescence spectroscopy and time-correlated single photon counting (TCSPC) in different aqueous solutions. The UV-vis spectra of the ZnPc(COOH)4/Fe3O4/Ch composite displays absorption by the aromatic rings, with a Q band exhibited at λ max = 702 nm. Moreover, the ZnPc(COOH)4/Fe3O4/Ch composite exhibits long triplet-state lifetimes of 1.6 μs and 12.3 μs, crucial for application as a photosensitizer. A triplet quantum yield of 0.56 for the ZnPc(COOH)4/Fe3O4/Ch composite in DMSO/H2O was achieved. FTIR showed that the conjugation of ZnPc(COOH)4 with Fe3O4/chitosan nanoparticles was achieved by electrostatic interaction.

Effect of permanganate oxidation on the photoreactivity of dissolved organic matter for photodegradation of typical pharmaceuticals

Permanganate has been widely used in the remediation of contaminated water due to its relatively strong oxidation properties and ease of use. The ubiquitous dissolved organic matter (DOM) in natural waters causes a significant sink of permanganate in treatments, which further impacts the photoformation of reactive species and the removal of trace pollutants by DOM. Significantly, the effect of permanganate oxidation on the photoreactivity of DOM remains unknown. The present paper investigated for the first time the photophysical and photochemical properties variation of DOM from different sources after permanganate oxidation. Results showed that the permanganate oxidation caused a decrease in UV absorbance, fluorescence intensity, aromaticity, and molecular weight for all tested DOM samples, as well as photoformation rate of DOM triplet states (3DOM⁎), singlet oxygen (1O2), and hydroxyl radical (OH) under simulated sunlight. Quantum yield of 1O2 showed positively linear correlations with both triplet quantum yield coefficient (fTMP) and E2/E3 (ratio of absorbance at 254 and 365 nm) for all the DOM samples before and after permanganate oxidation. The quantum yield of OH exhibited no significant correlation with fTMP or E2/E3. Permanganate oxidation inhibited the DOM-photosensitized indirect photodegradation of pollutants that do not absorb sunlight (e.g., decreased by 15–29%). For the tested pollutants that undergo direct photolysis under sunlight, their photodegradation was promoted (e.g., increased by 1–19%) in the permanganate oxidized DOM solutions due to the decrease of light-screening effect by DOM. These findings suggest that permanganate oxidation affects the photoreactivity of DOM and the corresponding photochemical fate of organic pollutants in natural waters.

Photodynamic therapy characteristics of phthalocyanines in the presence of boron doped detonation nanodiamonds: Effect of symmetry and charge

The synthesis, photophysicochemical and photodynamic therapy (PDT) activities of benzothiazole substituted zinc phthalocyanine (Pc): 1 (asymmetrically substituted and composed of no charges), 2 (asymmetrically substituted and composed of three positive charges), and 3 (symmetrically substituted and composed of four positive charges), are presented. The triplet and singlet oxygen quantum yields were highest for complex 2 showing the importance of asymmetry and charge. The complexes are covalently and non-covalently linked to B doped detonation nanodiamonds (B@DNDs) to yield nanohybrids (B@DNDs-1, B@DNDs-2, B@DNDs-3). The presence of B@DNDs, asymmetry and positive charge resulted in improved PDT with the lowest cell viability being observed for B@DNDs-2 at 5%. The cell viability ranged from 5% to 7% for the nanohybrids compared to 19–26% for Pcs alone.

Rubrene Nanoaggregate-Integrated CH3NH3PbI3 Bilayer Film: Role of Singlet Fission and Photon Upconversion

The potential to improve the efficiency of photovoltaic devices through singlet exciton fission (SF) has raised interest of researchers during the last decade. Organic small molecules of rubrene were fabricated into spherical nanoaggregates (NAs) of diameter ∼250 nm by the re-precipitation method. J-type aggregation inside the NA with pivotal electronic coupling occurs in NAs. Observed strong fluorescence quenching indicates the presence of competing pathways in the NAs: hot and thermally activated SF, triplet–triplet annihilation (TTA), and energy transfer between inhomogeneously broadened NA ensembles. SF which proceeds directly from upper excited electronic states within 340 fs (vs 200 fs in crystals; 30 fs in films) results in a triplet quantum yield of 162%. With an aim to apply rubrene in photovoltaics, a rubrene NA-integrated film was prepared on top of the CH3NH3PbI3 layer. Triplet formation within 25 ps in the NA layer was well-documented. Subsequently, the triplet excitons are accumulated and further upconverted via TTA to populate the conduction band of the perovskite within 39 ps (80%) and ≫10 ns (20%). Our findings are crucial for understanding photophysical mechanisms of rubrene/perovskite interaction after light absorption by rubrene.

Recent Advances in Bio‐Compatible Oxygen Singlet Generation and Its Tumor Treatment

AbstractLight‐dependent singlet oxygen (1O2) produced in photodynamic therapy (PDT), is a biologically compatible reactive oxygen species showing the potential to kill tumor cells with fewer side effects on nearby normal healthy cells. The development of a high 1O2 generating photosensitizer is a particularly demanding research areas. Based on Jablonski's diagram, the photophysical factors influencing the generation of 1O2 are intersystem crossing, triplet quantum yield and life, and the singlet‐triplet energy gap. Moreover, nanocarriers are also an emerging research topic with enhanced/localized delivery of photosensitizers to improve the dosage of light and enriched production of 1O2. In this review, the production principle of 1O2 in PDT and its killing mechanism with respect to tumor cells are reviewed. In addition, the progress of PDT has been supplemented in clinical applications in recent years and the emergent preclinical tactics for prospective solutions to these challenges are discussed to improve the effectiveness and usefulness of these procedures. Moreover, the remaining research gaps and future work is outlined. This review is anticipated to heighten the research for developing new strategies for modulating the photophysical properties and improved the delivery of photosensitizers.

Emerging Design Principle of Near-Infrared Upconversion Sensitizer Based on Mitochondria-Targeted Organic Dye for Enhanced Photodynamic Therapy.

Upconversion luminescent (UCL) triggered photodynamic therapy (PDT) affords superior outcome for cancer treatment. However, conventional UCL materials which all work by a multiphoton absorption (MPA) process inevitably need extremely high power density far over the maximum permissible exposure (MPE) to laser. Here, a one-photon absorption molecular upconversion sensitizer Cy5.5-Br based on frequency upconversion luminescent (FUCL) is designed for PDT. The unusual super heavy atom effect (SHAE) in Cy5.5-Br strongly enhances its spin-orbit coupling (0.23 cm-1 ), triplet quantum yield (11.1 %) and triplet state lifetime (18.8 μs) while the potential hot-band absorption of Cy5.5-Br is well maintained. Importantly, Cy5.5-Br can efficiently target the tumour site and kill cancer cells by destroying mitochondria under a biosafety MPE to 808 nm laser. The photostability and antitumor results are obviously superior to that of a Stokes process. This work provides a design criterion for FUCL dyes to realize effective PDT upon a biosafety optical density, possibly bringing more clinical benefits than conventional MPA materials.

Tunable Redox Potential Photocatalyst: Aggregates of 2,3-Dicyanopyrazino Phenanthrene Derivatives for the Visible-Light-Induced α-Allylation of Amines.

This work highlights the tunable redox potential of 6,11-dibromo-2,3-dicyanopyrazinophenanthrene (DCPP3) aggregates, which can be formed through physical π-π stacking interactions with other DCPP3 monomers. Electrochemical and scanning electron microscopy showed that the reduction potential of [DCPP3]n aggregates could be increased by decreasing their size. The size of [DCPP3]n aggregates could be regulated by controlling the concentration of DCPP3 in an organic solvent. As such, a fundamental understanding of this tunable redox potential is essential for developing new materials for photocatalytic applications. The [DCPP3]n aggregates as a visible-light photocatalyst in combination with Pd catalysts in the visible-light-induced α-allylation of amines were used. This [DCPP3]n photocatalyst exhibits excellent photo- and electrochemical properties, including a remarkable visible-light absorption, long excited-state lifetime (16.6 μs), good triplet quantum yield (0.538), and high reduction potential (Ered([DCPP3]n/[DCPP3]n-) > -1.8 V vs SCE).