A novel self-assembly based on double-layer zinc porphyrin sensitizers in supramolecular solar cell

Two new self-assemblies based on zinc porphyrin dyes ZnPx-ZnPA (x?=?1, 2) were synthesized and used for dye-sensitized solar cells. Capping layer dyes consist of zinc porphyrin (ZnP) as core unit and carbazole (P1), phenothiazine (P2) as electron-donating group. The dye ZnPA contains carboxylic group as an anchor porphyrin with upper dyes (denoted as ZnP1 and ZnP2) formed dyads by coordination bonds of Zn-to-ligand self-assembled devices. The assembly modes were also verified by transmission electron microscopy (TEM). The influence of the upper porphyrins on molecular structure as well as photovoltaic performance was investigated via photophysical and electrochemical studies and calculations. With addition of the phenothiazine unit, the ZnP2-ZnPA possesses better light-harvesting capability with a significantly red-shifted Q-band. The photoelectrochemical efficiencies for ZnP2-ZnPA are better than those of ZnP1-ZnPA ascribed to larger J_sc and V_oc.

     

A dye-sensitized solar cell containing an anchoring porphyrin

We have designed a self-assembly ZnP-ZnPA, based on a porphyrin ZnP bearing 1,3,5-triazine-2,4-diamine unit, and anchoring porphyrin ZnPA. The assembly with ZnP-ZnPA was immobilized on nanostructured TiO₂ electrode surfaces. The assembled structures were characterized by transmission electron microscopy. The optical, photovoltaic, electrochemical impedance spectroscopy, and incident photon-to-current conversion efficiency were measured. The results revealed that the ZnP-ZnPA device had better photovoltaic performance than ZnPA and possessed a higher shortcircuit photocurrent density (J_SC = 6.04) but a lower open-circuit photovoltage (V_OC = 0.51) than anchoring ZnPA. Moreover, our previously reported assembly (ZnP-A1) as reference, the assembly device ZnP-ZnPA had better η (2.24%) and FF (72.7%).     

New self-assemblies with zinc meso-tetra[3-(1H-imidazol-1-yl)phenyl] porphyrin for use in supramolecular solar cells

In this work, a new zinc meso-tetra[3-(1H-imidazol-1-yl)phenyl]porphyrin (ZnP) was synthesized. Further, the porphyrin ZnP was immobilized by metal-ligand axial coordination (ZnP-A) and a metal-ligand edged binding approach (ZnP-Zn-A) on the nanostructured TiO₂ electrode surface modified with coordinating ligand functionality, isonicotinic acid (A). The performances of the assemblies-sensitized solar cells were performed under irradiance of 100 mW?cm^?2 AM 1.5G sunlight. Photo-electrochemical studies reveal significantly improved performance of the assembly ZnP-A. These assemblies can afford a fertile base for further design and fabrication of new supramolecular solar cells in future.     

Role of the Bridge in Photoinduced Electron Transfer in Porphyrin–Fullerene Dyads

The role of π‐conjugated molecular bridges in through‐space and through‐bond electron transfer is studied by comparing two porphyrin–fullerene donor–acceptor (D–A) dyads. One dyad, ZnP–Ph–C₆₀ (ZnP=zinc porphyrin), incorporates a phenyl bridge between D and A and behaves very similarly to analogous dyads studied previously. The second dyad, ZnP–EDOTV–C₆₀, introduces an additional 3,4‐ethylenedioxythienylvinylene (EDOTV) unit into the conjugated bridge, which increases the distance between D and A, but, at the same time, provides increased electronic communication between them. Two essential outcomes that result from the introduction of the EDOTV unit in the bridge are as follows: 1) faster charge recombination, which indicates enhanced electronic coupling between the charge‐separated and ground electronic states; and 2) the disappearance of the intramolecular exciplex, which mediates photoinduced charge separation in the ZnP–Ph–C₆₀ dyad. The latter can be interpreted as a gradual decrease in electronic coupling between locally excited singlet states of D and A when introducing the EDOTV unit into the D–A bridge.     

Synthesis, excitation energy transfer and singlet oxygen photogeneration of covalently linked N-confused porphyrin-porphyrin and Zn(II) porphyrin dyads

Dyads of a N-confused porphyrin (NCP) moiety covalently linked to a porphyrin free-base (H₂P) or a zinc(II) porphyrinate (ZnP) moiety via a flexible alkyl chain of variable length have been synthesized. Photoluminescence study demonstrated an efficient excitation energy transfer from H₂P/ZnP moiety to the NCP moiety. Measurement of the near-IR emission of singlet oxygen produced by these dyads via photosensitization showed that the NCP-ZnP dyads (Ф_Δ = (0.61-0.65) ± 0.13) were better ¹O₂ generators than the NCP-P dyads (Ф_Δ = (0.36-0.41) ± 0.08).     

Charge‐Transfer State and Large First Hyperpolarizability Constant in a Highly Electronically Coupled Zinc and Gold Porphyrin Dyad

We report the synthesis and the characterizations of a novel dyad composed of a zinc porphyrin (ZnP) linked to a gold porphyrin (AuP) through an ethynyl spacer. The UV/Vis absorption spectrum and the electrochemical properties clearly reveal that this dyad exhibits a strong electronic coupling in the ground state as evidenced by shifted redox potentials and the appearance of an intense charge‐transfer band localized at λ=739 nm in dichloromethane. A spectroelectrochemical study of the dyad along with the parent homometallic system (i.e., ZnP–ZnP and AuP–AuP) was undertaken to determine the spectra of the reduced and oxidized porphyrin units. Femtosecond transient absorption spectroscopic analysis showed that the photoexcitation of the heterometallic dyad leads to an ultrafast formation of a charge‐separated state (⁺ZnP–AuP^.) that displays a particularly long lifetime (τ=4 ns in toluene) for such a short separation distance. The molecular orbitals of the dyad were determined by DFT quantum‐chemical calculations. This theoretical study confirms that the observed intense band at λ=739 nm corresponds to an interporphyrin charge‐transfer transition from the HOMO orbital localized on the zinc porphyrin to LUMO orbitals localized on the gold porphyrin. Finally, a Hyper–Rayleigh scattering study shows that the dyad possesses a large first molecular hyperpolarizability coefficient (β=2100×10^?30 esu at λ=1064 nm), thus highlighting the valuable nonlinear optical properties of this new type of push–pull porphyrin system.     

Remarkably Efficient Photocurrent Generation Based on a [60]Fullerene–Triosmium Cluster/Zn–Porphyrin/Boron–Dipyrrin Triad SAM

A new artificial photosynthetic triad array, a [60]fullerene–triosmium cluster/zinc–porphyrin/boron–dipyrrin complex ( 1 , Os₃C₆₀/ZnP/Bodipy), has been prepared by decarbonylation of Os₃(CO)₈(CN(CH₂)₃Si(OEt)₃)(μ₃‐η²:η²:η²‐C₆₀) ( 6 ) with Me₃NO/MeCN and subsequent reaction with the isocyanide ligand CNZnP/Bodipy ( 5 ) containing zinc porphyrin (ZnP) and boron dipyrrin (Bodipy) moieties. Triad 1 has been characterized by various spectroscopic methods (MS, NMR, IR, UV/Vis, photoluminescence, and transient absorption spectroscopy). The electrochemical properties of 1 in chlorobenzene (CB) have been examined by cyclic voltammetry; the general feature of the cyclic voltammogram of 1 is nine reversible one‐electron redox couples, that is, the sum of those of 5 and 6 . DFT has been applied to study the molecular and electronic structures of 1 . On the basis of fluorescence‐lifetime measurements and transient absorption spectroscopic data, 1 undergoes an efficient energy transfer from Bodipy to ZnP and a fast electron transfer from ZnP to C₆₀; the detailed kinetics involved in both events have been elucidated. The SAM of triad 1 ( 1 /ITO; ITO=indium–tin oxide) has been prepared by immersion of an ITO electrode in a CB solution of 1 and diazabicyclo‐octane (2:1 equiv), and characterized by UV/Vis absorption spectroscopy, water contact angle, X‐ray photoelectron spectroscopy, and cyclic voltammetry. The photoelectrochemical properties of 1 /ITO have been investigated by a standard three‐electrode system in the presence of an ascorbic acid sacrificial electron donor. The quantum yield of the photoelectrochemical cell has been estimated to be 29 % based on the number of photons absorbed by the chromophores. Our triad 1 is unique when compared to previously reported photoinduced electron‐transfer arrays, in that C₆₀ is linked by π bonding with little perturbation of the C₆₀ electron delocalization.     

A Supramolecular Tetrad Featuring Covalently Linked Ferrocene–Zinc Porphyrin–BODIPY Coordinated to Fullerene: A Charge Stabilizing,Photosynthetic Antenna–Reaction Center Mimic

A novel photosynthetic‐antenna–reaction‐center model compound, comprised of BF₂‐chelated dipyrromethene (BODIPY) as an energy‐harvesting antenna, zinc porphyrin (ZnP) as the primary electron donor, ferrocene (Fc) as a hole‐shifting agent, and phenylimidazole‐functionalized fulleropyrrolidine (C₆₀Im) as an electron acceptor, has been synthesized and characterized. Optical absorption and emission, computational structure optimization, and cyclic voltammetry studies were systematically performed to establish the role of each entity in the multistep photochemical reactions. The energy‐level diagram established from optical and redox data helped identifying different photochemical events. Selective excitation of BODIPY resulted in efficient singlet energy transfer to the ZnP entity. Ultrafast electron transfer from the ¹ZnP* (formed either as a result of singlet–singlet energy transfer or direct excitation) or ¹C₆₀* of the coordinated fullerene resulting into the formation of the Fc–(C₆₀ ^{. ?}Im:ZnP ^{. +})–BODIPY radical ion pair was witnessed by femtosecond transient absorption studies. Subsequent hole migration to the ferrocene entity resulted in the Fc⁺–(C₆₀ ^{. +}Im:ZnP)–BODIPY radical ion pair that persisted for 7–15 μs, depending upon the solvent conditions and contributions from the triplet excited states of ZnP and ImC₆₀, as revealed by the nanosecond transient spectral studies. Better utilization of light energy in generating the long‐lived charge‐separated state with the help of the present “antenna–reaction‐center” model system has been successfully demonstrated.     

Tetrathiafulvalene‐Fused Porphyrins via Quinoxaline Linkers: Symmetric and Asymmetric Donor–Acceptor Systems

A tetrathiafulvalene (TTF) donor is annulated to porphyrins (P) via quinoxaline linkers to form novel symmetric P–TTF–P triads 1 a – c and asymmetric P–TTF dyads 2 a , b in good yields. These planar and extended π‐conjugated molecules absorb light over a wide region of the UV/Vis spectrum as a result of additional charge‐transfer excitations within the donor–acceptor assemblies. Quantum‐chemical calculations elucidate the nature of the electronically excited states. The compounds are electrochemically amphoteric and primarily exhibit low oxidation potentials. Cyclic voltammetric and spectroelectrochemical studies allow differentiation between the TTF and porphyrin sites with respect to the multiple redox processes occurring within these molecular assemblies. Transient absorption measurements give insight into the excited‐state events and deliver corresponding kinetic data. Femtosecond transient absorption spectra in benzonitrile may suggest the occurrence of fast charge separation from TTF to porphyrin in dyads 2 a , b but not in triads 1 a – c . Clear evidence for a photoinduced and relatively long lived charge‐separated state (385 ps lifetime) is obtained for a supramolecular coordination compound built from the ZnP–TTF dyad and a pyridine‐functionalized C₆₀ acceptor unit. This specific excited state results in a (ZnP–TTF)^?+ ??? (C₆₀py)^?? state. The binding constant of Zn^II ??? py is evaluated by constructing a Benesi–Hildebrand plot based on fluorescence data. This plot yields a binding constant K of 7.20×10⁴ M ^?1, which is remarkably high for bonding of pyridine to ZnP.     

Cobalt(II) porphyrin axially coordinated with 2′-(pyridin-4-yl)-5′-(pyridin-2-yl)-1′-(pyridin-2-ylmethyl)-2′,4′-dihydro-1′H-pyrrolo[3′,4′ : 1,2](C60-Ih)[5,6]fullerene: formation,chemical structure,and spectroscopic properties

Construction of new effective photovoltaic devices based on organic dyes has important implications for modern and future technologies. In this article, we studied the equilibrium, the rate, and the spectral manifestation of the reaction of [(2,3,7,8,12,18-hexamethyl,13,17-diethyl,5-(2-pyridyl)porphyrinato)cobalt(II)]–[2′-(pyridin-4-yl)-5′-(pyridin-2-yl)-1′-(pyridin-2-ylmethyl)-2′,4′-dihydro-1′H-pyrrolo[3′,4′ : 1,2](C₆₀-I_h)[5,6]fullerene] triad formation as well as its spectral properties and photo electrochemical behavior. The cobalt porphyrin–pyridyl-substituted fullerene mixtures in toluene are self-assembling systems due to axial donor–acceptor binding between Co of the porphyrin complex and N-pyridyl of the substituted fullerene. The formation rate constant, k^298K, and the stability constant, K^298K, of donor–acceptor triad formed by coordination of two substituted fullerene molecules to Co porphyrin are (44.4 ± 0.8) mol L^?1 s^?1 and (56 ± 16)×10⁷ L² mol^?2, respectively. Modification of the titanium electrode coated with the natural oxide film was carried out using the porphyrin–fullerene triad and its individual components. Photopotential and photocurrent density of the system with modified electrode were studied. The obtained results are of interest for creating porphyrin-based donor–acceptor systems as components in organic photovoltaics.     

Synthesis and Spectroscopic Properties of a Covalently Linked Porphyrin–Fullerene C60 Dyad

A covalently linked porphyrin–fullerene C₆₀ dyad 6 was conveniently synthesized by 1,3‐dipolar cycloaddition using 5‐(4‐carbonylphenyl)‐10,15,20‐tris(4‐methoxylphenyl)porphyrin 5, N‐methylglycine and fullerene C₆₀. Spectroscopic studies show that dyad 6 is a promising architecture with potential application as photoactive organic material.     

Redox Active Two‐Component Films of Palladium and Covalently Linked Zinc Porphyrin–Fullerene Dyad

Redox active films have been generated electrochemically by the reduction of dyads consisting of fullerene C₆₀ covalently linked to zinc meso‐tetraphenyloporphyrin, ZnP? C₆₀, and palladium acetate. The films are believed to consist of a polymeric network formed via covalent bonds between the palladium atoms and the fullerene moieties. In these films, the zinc porphyrin moiety is covalently linked to the polymeric chains through the pyrrolidine ring of the fullerene. The ZnP? C₆₀/Pt films are electrochemically active in both positive and negative potential excursions. At positive potentials, two oxidation steps for the zinc porphyrin are observed. In the negative potential range, electron transfer processes involving the zinc porphyrin and the fullerene entities are observed. Film formation is also accompanied by palladium deposition on the electrode surface. The presence of a metallic phase in the film influences its morphology, structure and electrochemical properties.     

A Carbon Nanohorn?Porphyrin Supramolecular Assembly for Photoinduced Electron‐Transfer Processes

A supramolecular assembly of zinc porphyrin? carbon nanohorns ( CNH s) was constructed in a polar solvent. An ammonium cation was covalently connected to the CNH through a spacer (sp) ( CNH ‐sp‐NH₃⁺) and bound to a crown ether linked to a zinc porphyrin (Crown? ZnP). Nanohybrids CNH ‐sp‐NH₃⁺;Crown? ZnP and CNH ‐sp‐NH₃⁺ were characterized by several techniques, such as high‐resolution transmission electron microscopy, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and Raman spectroscopy. The photoinduced electron‐transfer processes of the nanohybrids have been confirmed by using time‐resolved absorption and fluorescence measurements by combining the steady‐state spectral data. Fluorescence quenching of the ZnP unit by CNH ‐sp‐NH₃⁺ has been observed, therefore, photoinduced charge separation through the excited singlet state of the ZnP unit is suggested for the hybrid material, CNH ‐sp‐NH₃⁺;Crown? ZnP. As transient absorption spectral experiments reveal the formation of the radical cation of the ZnP unit, electron generation is suggested as a counterpart of the charge‐separation on the CNH s; such an electron on the CNH s is further confirmed by migrating to the hexylviologen dication (HV²⁺). Accumulation of the electron captured from HV^.+ is observed as electron pooling in solution in the presence of a hole‐shifting reagent. Photovoltaic performance with moderate efficiency is confirmed for CNH‐ sp‐NH₃⁺;Crown? ZnP deposited onto nanostructured SnO₂ films.     

Supramolecular Tetrad Featuring Covalently Linked Bis(porphyrin)–Phthalocyanine Coordinated to Fullerene: Construction and Photochemical Studies

A multimodular donor–acceptor tetrad featuring a bis(zinc porphyrin)–(zinc phthalocyanine) ((ZnP–ZnP)–ZnPc) triad and bis‐pyridine‐functionalized fullerene was assembled by a “two‐point” binding strategy, and investigated as a charge‐separating photosynthetic antenna‐reaction center mimic. The spectral and computational studies suggested that the mode of binding of the bis‐pyridine‐functionalized fullerene involves either one of the zinc porphyrin and zinc phthalocyanine (Pc) entities of the triad or both zinc porphyrin entities leaving ZnPc unbound. The binding constant evaluated by constructing a Benesi–Hildebrand plot by using the optical data was found to be 1.17×10⁵ M ^?1, whereas a plot of “mole‐ratio” method revealed a 1:1 stoichiometry for the supramolecular tetrad. The mode of binding was further supported by differential pulse voltammetry studies, in which redox modulation of both zinc porphyrin and zinc phthalocyanine entities was observed. The geometry of the tetrad was deduced by B3LYP/6‐31G* optimization, whereas the energy levels for different photochemical events was established by using data from the optical absorption and emission, and electrochemical studies. Excitation of the zinc porphyrin entity of the triad and tetrad revealed ultrafast singlet–singlet energy transfer to the appended zinc phthalocyanine. The estimated rate of energy transfer (k_ENT) in the case of the triad was found to be 7.5×10¹¹ s^?1 in toluene and 6.3×10¹¹ s^?1 in o‐dichlorobenzene, respectively. As was predicted from the energy levels, photoinduced electron transfer from the energy‐transfer product, that is, singlet‐excited zinc phthalocyanine to fullerene was verified from the femtosecond‐transient spectral studies, both in o‐dichlorobenzene and toluene. Transient bands corresponding to ZnPc ^{? +} in the 850 nm range and C₆₀ ^{? ?} in the 1020 nm range were clearly observed. The rate of charge separation, k_CS, and rate of charge recombination, k_CR, for the (ZnP–ZnP)–ZnPc ^{? +}:Py₂C₆₀ ^{? ?} radical ion pair (from the time profile of 849 nm peak) were found to be 2.20×10¹¹ and 6.10×10⁸ s^?1 in toluene, and 6.82×10¹¹ and 1.20×10⁹ s^?1 in o‐dichlorobenzene, respectively. These results revealed efficient energy transfer followed by charge separation in the newly assembled supramolecular tetrad.     

Wet-Chemically Prepared Porphyrin Layers on Rutile TiO2(110)

Porphyrins are large organic molecules that are interesting for different applications, such as photovoltaic cells, gas sensors, or in catalysis. For many of these applications, the interactions between adsorbed molecules and surfaces play a crucial role. Studies of porphyrins on surfaces typically fall into one of two groups: (1) evaporation onto well-defined single-crystal surfaces under well-controlled ultrahigh vacuum conditions or (2) more application-oriented wet chemical deposition onto less well-defined high surface area surfaces under ambient conditions. In this study, we will investigate the wet chemical deposition of 5-(monocarboxyphenyl)-10,15,20-triphenylporphyrin (MCTPP) on well-defined rutile TiO₂(110) single crystals under ambient conditions. Prior to deposition, the TiO₂(110) crystals were also cleaned wet-chemically under ambient conditions, meaning none of the preparation steps were done in ultrahigh vacuum. However, after each preparation step, the surfaces were characterized in ultrahigh vacuum with X-ray photoelectron spectroscopy (XPS) and the result was compared with porphyrin layers prepared in ultrahigh vacuum (UHV) by evaporation. The differences of both preparations when exposed to zinc ion solutions will also be discussed.     

A Light-Harvesting/Charge-Separation Model with Energy Gradient Made of Assemblies of meta-Pyridyl Zinc Porphyrins

Self-assembly of porphyrins is a fascinating topic, not only for mimicking chlorophyll assemblies in photosynthetic organisms, but also for the potential of creating molecular-level devices. Herein, zinc porphyrin derivatives bearing a meta-pyridyl group at the meso position were prepared and their assemblies studied in chloroform. Among the porphyrins studied, one with a carbamoylpyridyl moiety gave a distinct ¹H NMR spectrum in CDCl₃, which allowed the supramolecular structure in solution to be probed in detail. Ring-current-induced chemical-shift changes in the ¹H NMR spectrum, together with vapor-pressure osmometry and diffusion-ordered NMR spectroscopy, among other evidence, suggested that the porphyrin molecules form a trimer with a triangular cone structure. Incorporation of a directly linked porphyrin–ferrocene dyad with the same assembling properties in the assemblies led to a rare example of a light-harvesting/charge-separation system in which an energy gradient is incorporated and reductive quenching occurs.     

Designs,Synthesis, Characterization and Direct Electrochemistry of Zinc‐Porphyrin Bearing Pyrene Noncovalent Functionalized Graphene Oxide Sheet

We have designed and synthesis a new compound of zinc‐porphyrin bearing four pyrene groups (ZnP‐t‐P(py)₄) and prepared a new hybrid materials of ZnP‐t‐P(py)₄ with graphene oxide (GO) via non‐covalent interactions. The ZnP‐t‐P(py)₄, along with four pendant pyrene entities ZnP‐t‐P(py)₄, stacking on the (GO) surface due to π‐ π interactions, has been revealed by AFM measurements. FTIR, UV‐vis absorption confirm the non‐covalent functionalization of the GO. Raman spectral measurements revealed the electronic structure of the GO to be intact upon hybrid formation. In this donor‐acceptor nanohybrid, the fluorescence of photoexcited ZnP‐t‐P(py)₄ is effectively quenched by a possible electron‐transfer process. The fluorescence and photoelectrical response measurements also showed that this hybrid may act as an efficient photoelectric conversion material for optoelectronic applications.     

Synthesis,Optical and Photovoltaic Properties of Porphyrin Dyes

The synthesis and optical absorption of a series of porphyrins, and the photoelectrochemical properties of TiO₂ solar cells sensititized with these porphyrins was investigated. The different types of porphyrins studied are designated by numbers: the reference compound 1 (Zinc(II) 5,15-bis(4-carboxylphenyl)porphyrin), porphyrin substituted with one triarylamine unit 2, and porphyrin substituted with two triarylamine units 3. The UV-Vis absorption spectra reveal that the substitutions result in large redshifts in both the Soret band (～ 60 nm) and the Q bands (～ 125 nm), as well as enhancement of optical absorption. The enhancement is even more pronounced in the long-wavelength region of 575–725 nm, where the absorption of porphyrin 3 is eight times that of porphyrin 1. The photoelectrochemical properties of the porphyrins were also studied by constructing porphyrin-sensitized TiO₂ solar cells. Under standard AM 1.5 sunlight, the porphyrin 1 cell yields a short-circuit current of ～ 1.26 mA/cm², an open-circuit voltage of ～ 0.564 V, and a fill factor of ～ 61%. The incident photon-to-current conversion efficiency is ～ 24% for porphyrin 1 and ～ 5–7% for porphyrins 2 and 3 at the Soret peak.     

Photoinduced hydrogen evolution with water soluble bisviologen linked zinc porphyrin and hydrogenase

Water soluble bisviologen linked zinc porphyrin (ZnP(C₄V_AC₄V_B)₄) was synthesized and characterized. The quenching processes of the photoexcited singlet state and triplet state of ZnP(C₄V_AC₄V_B)₄ were measured by using fluorescence lifetime and laser flash photolysis. The photoexcited singlet state of the zinc porphyrin was quenched by the bonded bisviologen. Photoinduced hydrogen evolution with ZnP(C₄V_AC₄V_B)₄ and hydrogenase was observed under steady state irradiation.     

Multipolar Porphyrin-Triazatruxene Arrays for Two-Photon Fluorescence Cell Imaging

Two-photon excited fluorescent (TPEF) materials are highly desirable for bioimaging applications owing to their unique characteristics of deep-tissue penetration and high spatiotemporal resolution. Herein, by connecting one, two, or three electron-deficient zinc porphyrin units to an electron-rich triazatruxene core via ethynyl π-bridges, conjugated multipolar molecules TAT-(ZnP) _n (n=1–3) were developed as TPEF materials for cell imaging. The three new dyes present high fluorescence quantum yields (0.40–0.47) and rationally improved two-photon absorption (TPA) properties. In particular, the peak TPA cross section of TAT-ZnP (436 GM) is significantly larger than that of the ZnP reference (59 GM). The δ_TPA values of TAT-(ZnP)₂ and TAT-(ZnP)₃ further increase to 1031 and up to 1496 GM, respectively, indicating the effect of incorporated ZnP units on the TPA properties. The substantial improvement of the TPEF properties is attributed to the formation of π-conjugated quadrapole/octupole molecules and the extension of D -π-A-D systems, which has been rationalized by density function theory (DFT) calculations. Moreover, all of the three new dyes display good biocompatibility and preferential targeting ability toward cytomembrane, thus can be superior candidates for TPEF imaging of living cells. Overall, this work demonstrated a promising strategy for the development of porphyrin-based TPEF materials by the construction and extension of D -π-A-D multipolar array.