Zinc(II) tetraarylporphyrins anchored to TiO2, ZnO, and ZrO2 nanoparticle films through rigid-rod linkers

Rod-like nanostructures through amphiphilic OPE-porphyrin self-organization

A new amphiphilic monosubstituted porphyrin functionalized by a β-D-glucoside terminated oligophenylenethylene (OPE) able to self-arrange into nano-aggregates in polar solvents has been synthesized and fully characterized in its monomeric and aggregated forms.

Controlling Electronic Coupling of Acene Chromophores on Quantum Dot Surfaces through Variable-Concentration Ligand Exchange

Controlling the binding of functional organic molecules on quantum dot (QD) surfaces and the resulting ligand/QD interfacial structure determines the resulting organic-inorganic hybrid behavior. In this study, we vary the binding of tetracenedicarboxylate ligands bound to PbS QDs cast in thin films by performing solid-state ligand exchange of as-produced bound oleate ligands. We employ comprehensive Fourier-transform infrared (FTIR) analysis coupled with ultraviolet-visible (UV-vis) spectrophotometric measurements, transient absorption, and Density Functional Theory (DFT) simulations to study the QD/ligand surface structure and resulting optoelectronic properties. We find that there are three primary QD/diacid structures, each with a distinct binding mode dictated by the QD-ligand and ligand-ligand intermolecular and steric interactions. They can be accessed nearly independently of one another via different input ligand concentrations. Low concentrations produce mixed oleate/tetracene ligand structures where the tetracene carboxylates tilt toward QD surfaces. Intermediate concentrations produce mixed oleate/tetracene ligand structures with ligand-ligand interactions through intramolecular hydrogen bonding with the ligands perpendicular to the QD surface and weaker QD/ligand electronic interactions. High concentrations result in full ligand exchange, and the ligands tilt toward the surface while the QD film compacts. When the tetracene ligands tilt or lie flat on the QD surface, the benzene ring π-system interacts strongly with the p-orbitals at the PbS surface and produces strong QD-ligand interactions evidenced through QD/ligand state mixing, with a coupling energy of ≈700 meV.

Anchoring of carboxyl-functionalized porphyrins on MgO, TiO2, and Co3O4 nanoparticles

Hybrid materials consisting of functional organic molecules on metal oxide nanomaterials are key components in emerging technologies, for example in energy conversion and molecular electronics. In this work, we present the results of a comparative study of carboxyl-functionalized porphyrins on different oxide nanomaterials. Specifically, we investigated the interaction of 5(3-carboxyphenyl)-10,15,20-triphenyl-21,23H-porphyrin (2H-3-MCTPP) and 5(4-carboxyphenyl)-10,15,20-triphenyl-21,23H-porphyrin (2H-4-MCTPP), on MgO, TiO2, and Co3O4 nanoparticles (NPs) using isothermal and temperature-programmed diffuse reflection infrared Fourier transform spectroscopy (DRIFTS). We show that both porphyrins bind to the NPs, yielding stable monolayer films consisting of tilted surface carboxylates. In all cases, anchoring through the carboxylic acid group suppresses self-metalation of the porphyrin unit. Upon annealing, all anchored porphyrin films undergo metalation. The position of the acid group has no major influence on the reactivity. The same is true for the nature of the metal oxide, suggesting that the observed behaviour is general for most anchored porphyrin films on oxide nanomaterials.

Tenacic Acids: A New Class of Tenacious Binders to Metal Oxide Surfaces

The backbone of 2-hydroxyisophthalic acid was identified as a potential metal oxide anchor because of the perfect alignment of all three of its donor groups for binding to inorganic surfaces. It can therefore be used in the design of organic linkers for metal oxide based hybrid materials. Optimized and scalable methods for the synthesis of 2-hydroxyisophthalic acid (1) and its 5-substituted derivatives: 5-bromo- (2), 5-sulfooxy- (3), 5-hydroxy- (4), and 5-PEG600 (5) are presented. Dynamic light scattering (DLS) demonstrated that compound 2 inhibits Fe(OH)3 precipitation when FeIII aqueous solutions are titrated with NaOH, while similar titrations in the presence of the structurally-related isophthalic and salicylic acids, both missing the third donor group, show turbidity at pHs as low as 2.3 and 3.5, respectively. The adduct synthesized from 4.5 nm γ-Fe2 O3 nanoparticles and 5 is water-, alcohol- and CH2 Cl2 -soluble, and forms stable aqueous colloids in the pH range of 4.4-8.7. Moreover, at a pH close to neutral these colloids survive at 100 °C, demonstrating the high practicality of 2-hydroxyisophthalic acid for nanoparticulate inorganic/organic hybrid material design.

Thermally Activated Self-metalation of Carboxy-functionalized Porphyrin Films on MgO Nanocubes

We investigated the adsorption of different free-base carboxyl-functionalized porphyrins, 5,10,15,20-tetrakis(4-carboxyphenyl)-21,23H-porphyrin (2H-TCPP) and 5(4-carboxyphenyl)-10,15,20-triphenyl-21,23H-porphyrin (2H-MCTPP), on MgO nanocubes combining IR, UV/Vis and photoluminescence emission spectroscopy. The thermal behavior of the films was monitored in-situ during annealing. Both porphyrins bind to the nanocubes via one and two acid groups respectively, yielding monolayer films consisting of tilted molecules. For 2H-TCPP, two acid groups remain free and give rise to a characteristic IR band. Self-assembly in a tilted adsorbate layer suppresses metalation at room temperature, in contrast to non-functionalized 2H-TPP, which adsorbs flat-lying. Upon heating, 2H-MCTPP undergoes full metalation at temperatures below 280 °C, whereas 2H-TCPP does not metalate at all. The hindered metalation reaction is attributed to the rigidity of the adsorbate film preventing complexation. Our results show that the properties of porphyrin films on oxides can be tuned in a wide range via the position and arrangement of carboxyl anchoring groups.

Determinants of the efficiency of photon upconversion by triplet-triplet annihilation in the solid state: zinc porphyrin derivatives in PVA

Spectroscopic, photophysical and computational studies designed to expose and explain the differences in the efficiencies of non-coherent photon upconversion (NCPU) by triplet-triplet annihilation (TTA) have been carried out for a new series of alkyl-substituted diphenyl and tetraphenyl zinc porphyrins, both in fluid solution and in solid films. Systematic variations in the alkyl-substitution of the phenyl groups in both the di- and tetraphenyl porphyrins introduces small, but well-understood changes in their spectroscopic and photophysical properties and in their TTA efficiencies. In degassed toluene solution TTA occurs for all derivatives and produces the fluorescent S₂ product states in all cases. In PVA matrices, however, none of the di-phenylporphyrins exhibit measurable NCPU whereas all the tetraphenyl-substituted compounds remain upconversion-active. In PVA the NCPU efficiencies of the zinc tetraphenylporphyrins vary significantly with their steric characteristics; the most sterically crowded tetraphenyl derivative exhibits the greatest efficiency. DFT-D computations have been undertaken and help reveal the sources of these differences.

Synthesis and characterization of zinc carboxy–porphyrin complexes for dye sensitized solar cells

DOTA-like porphyrin Zn complexes 8 afford new perspectives in DSSCs compared to mono-porphyrin counterpart 2, by displaying a PCE (%) of 7.13.

Synthesis and photophysical properties of a porphyrin–BODIPY dyad and a porphyrin–o-carborane–BODIPY triad

The photophysical and electrochemical properties of a newly synthesized porphyrin–BODIPY dyad and a porphyrin–o-carborane–BODIPY triad have been investigated.

Probing single-molecule electron-hole transfer dynamics at a molecule-NiO semiconductor nanocrystalline interface

Interfacial charge transfer dynamics in dye-sensitized NiO nanoparticles are being investigated for photocathodes in p-type dye-sensitized solar cells. In the photoreaction, after fast electron transfer from NiO to a molecule, the recombination of the hole in the nanoparticles with the electron in a reduced molecule plays an important role in the charge separation process and solar energy harvesting. Nevertheless, knowledge of the interfacial charge recombination (CR) rate and its mechanism is still limited due to the complex photoinduced electron and hole dynamics and lack of characterization of the inhomogeneity of the dynamics. Here, we report our work on probing interfacial charge recombination dynamics in Zn(ii)-5,10,15,20-tetra(3-carboxyphenyl)porphyrin (m-ZnTCPP) dye-sensitized NiO nanoparticles by correlating single-molecule fluorescence blinking dynamics with charge transfer dynamics using single-molecule photon-stamping spectroscopy. The correlated analyses of single-molecule fluorescence intensity, lifetime, and blinking reveal the intrinsic distribution and temporal fluctuation of interfacial charge transfer reactivity, which are closely related to site-specific molecular interactions and dynamics.

ZnO nanorods assembled with different porphyrins – size-tunable hybrid particles

We present a fundamental study on ZnO nanorod–porphyrin assembly formation in solution, providing the key to novel tunable hybrid assemblies with potential in solar energy conversion.

Covalent functionalization of reduced graphene oxide with porphyrin by means of diazonium chemistry for nonlinear optical performance

Reduced graphene oxide (RGO)-porphyrin (TPP) nanohybrids (RGO-TPP 1 and RGO-TPP 2) were prepared by two synthetic routes that involve functionalization of the RGO using diazonium salts. The microscopic structures, morphology, photophysical properties and nonlinear optical performance of the resultant RGO-TPP nanohybrids were investigated. The covalent bonding of the porphyrin-functionalized-RGO nanohybrid materials was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and thermogravimetric analysis. Attachment of the porphyrin units to the surface of the RGO by diazotization significantly improves the solubility and ease of processing of these RGO-based nanohybrid materials. Ultraviolet/visible absorption and steady-state fluorescence studies indicate considerable π-π interactions and effective photo-induced electron and/or energy transfer between the porphyrin moieties and the extended π-system of RGO. The nonlinear optical properties of RGO-TPP 1 and RGO-TPP 2 were investigated by open-aperture Z-scan measurements at 532 nm with both 4 ns and 21 ps laser pulses, the results showing that the chemical nanohybrids exhibit improved nonlinear optical properties compared to those of the benchmark material C₆₀, and the constituent RGO or porphyrins.

Heterogeneous Electron-Transfer Dynamics through Dipole-Bridge Groups

Heterogeneous electron transfer (HET) between photoexcited molecules and colloidal TiO2 has been investigated for a set of Zn-porphyrin chromophores attached to the semiconductor via linkers that allow to change level alignment by 200 meV by reorientation of the dipole moment. These unique dye molecules have been studied by femtosecond transient absorption spectroscopy in solution and adsorbed on the TiO2 colloidal film in vacuum. In solution energy transfer from the excited chromophore to the dipole group has been identified as a slow relaxation pathway competing with S2-S1 internal conversion. On the film heterogeneous electron transfer occurred in 80 fs, much faster compared to all intramolecular pathways. Despite a difference of 200 meV in level alignment of the excited state with respect to the semiconductor conduction band, identical electron transfer times were measured for different linkers. The measurements are compared to a quantum-mechanical model that accounts for electronic-vibronic coupling and finite band width for the acceptor states. We conclude that HET occurs into a distribution of transition states that differs from regular surface states or bridge mediated states.

Synthesis of porphyrin sensitizers with a thiazole group as an efficient π-spacer: potential application in dye-sensitized solar cells

CNU-OC8 exhibits better photovoltaic performance than the benchmark YD2-OC8 sensitizer in a liquid I⁻/I₃⁻ redox electrolyte.

Can nitro groups really anchor onto TiO2? Case study of dye-to-TiO2adsorption using azo dyes with NO2substituents

Molecular rationalization of the photovoltaic performance of dye-sensitized solar cells that employ azo dyes bearing a NO₂anchoring group.

Spectroscopic and Structural Studies of a Surface Active Porphyrin in Solution and in Langmuir-Blodgett Films

Controlling aggregation of the dual sensitizer-emitter (S-E) zinc tetraphenylporphyrin (ZnTPP) is an important consideration in solid state noncoherent photon upconversion (NCPU) applications. The Langmuir-Blodgett (LB) technique is a facile means of preparing ordered assemblies in thin films to study distance-dependent energy transfer processes in S-E systems and was used in this report to control the aggregation of a functionalized ZnTPP on solid substrates. This was achieved by synthetic addition of a short polar tail to one of the pendant phenyl rings in ZnTPP in order to make it surface active. The surface active ZnTPP derivative formed rigid films at the air-water interface and exhibited mean molecular areas consistent with approximately vertically oriented molecules under appropriate film compression. A red shift in the UV-vis spectra as well as unquenched fluorescence emission of the LB films indicated formation of well-ordered aggregates. However, NCPU, present in the solution phase, was not observed in the LB films, suggesting that NCPU from ZnTPP as a dual S-E required not just a controlled aggregation but a specific orientation of the molecules with respect to each other.

Synthesis and Antiviral Activity Evaluation of Nitroporphyrins and Nitrocorroles as Potential Agents against Human Cytomegalovirus Infection

Different nitroporphyrinoid derivatives were synthesized and studied as potential agents against human Cytomegalovirus. Interestingly, two nitrocorroles display strong activity against human Cytomegalovirus with IC 50 < 0.5 μM. These compounds also possess antiproliferative activities without detected in vivo toxicity. Therefore, nitrocorroles appear for the first time as potential active compounds that can be applied in human health.

Facile synthesis, spectroscopic and electrochemical properties, and theoretical calculations of porphyrin dimers with a bridging amide-bonded xanthene moiety

A free base porphyrin dimer bridged by a flexible amide-bonded xanthene moiety and its binuclear zinc(II) complex zinc(II) complex were synthesized and characterized. Structural characterization by MS and 1 H NMR spectroscopy confirmed the bridged porphyrin dimer structure. The properties of the dimers were characterized by IR, UV-visible absorption, fluorescence and magnetic circular dichroism (MCD) spectroscopy, and electrochemistry studies. Theoretical calculations were carried out to analyze the electronic structures of porphyrin dimers with a bridging amide-bonded xanthene moiety.

Free-Base Carboxyphenyl Porphyrin Films Using a TiO₂ Columnar Matrix: Characterization and Application as NO₂ Sensors

The anchoring effect on free-base carboxyphenyl porphyrin films using TiO₂ microstructured columns as a host matrix and its influence on NO₂ sensing have been studied in this work. Three porphyrins have been used: 5-(4-carboxyphenyl)10,15,20-triphenyl-21H,23H-porphyrin (MCTPP); 5,10,15,20-tetrakis(4-carboxyphenyl)-21H,23H-porphyrin (p-TCPP); and 5,10,15,20-tetrakis(3-carboxyphenyl)-21H,23H-porphyrin (m-TCPP). The analysis of UV-Vis spectra of MCTPP/TiO₂, p-TCPP/TiO₂ and m-TCPP/TiO₂ composite films has revealed that m-TCPP/TiO₂ films are the most stable, showing less aggregation than the other porphyrins. IR spectroscopy has shown that m-TCPP is bound to TiO₂ through its four carboxylic acid groups, while p-TCPP is anchored by only one or two of these groups. MCTPP can only be bound by one carboxylic acid. Consequently, the binding of p-TCPP and MCTPP to the substrate allows them to form aggregates, whereas the more fixed anchoring of m-TCPP reduces this effect. The exposure of MCTPP/TiO₂, p-TCPP/TiO₂ and m-TCPP/TiO₂ films to NO₂ has resulted in important changes in their UV-Vis spectra, revealing good sensing capabilities in all cases. The improved stability of films made with m-TCPP suggests this molecule as the best candidate among our set of porphyrins for the fabrication of NO₂ sensors. Moreover, their concentration-dependent responses upon exposure to low concentrations of NO₂ confirm the potential of m-TCPP as a NO₂ sensor.

Photoelectrochemical properties of porphyrin dyes with a molecular dipole in the linker

The electronic properties of three porphyrin–bridge–anchor photosensitizers are reported with (1a, 1e, 3a and 3e) or without (2a and 2e) an intramolecular dipole in the bridge. The presence and orientation of the bridge dipole is hypothesized to influence the photovoltaic properties due to variations in the intrinsic dipole at the semiconductor–molecule interface. Electrochemical studies of the porphyrin–bridge–anchor dyes self-assembled on mesoporous nanoparticle ZrO₂ films, show that the presence or direction of the bridge dipole does not have an observable effect on the electronic properties of the porphyrin ring. Subsequent photovoltaic measurements of nanostructured TiO₂ semiconductor films in dye sensitized solar cells show a reduced photocurrent for photosensitizers 1a and 3a containing a bridge dipole. However, cooperative increased binding of the 1a + 3a co-sensitized device demonstrates that dye packing overrides any differences due to the presence of the small internal dipole.

Synthesis of 5,10,15,20-tetrakis[4-(naphthalen-2-yloxycarbonyl)phenyl]porphyrin (TNBP) and its complexes with zinc and cobalt and an investigation of the photocatalytic activity of nanoFe3O4@ZrO2–TNBP

5,10,15,20-Tetrakis[4-(naphthalen-2-yloxycarbonyl)phenyl]porphyrin and its porphyrin complexes with zinc and cobalt and nanoFe₃O₄@ZrO₂–TNBP photocatalysts were synthesized with high yields and the structure and morphology were fully characterized.

Mono- and tri-β-substituted unsymmetrical metalloporphyrins: synthesis, structural, spectral and electrochemical properties

Mono-/tri-β-substituted metalloporphyrins have been synthesized and characterized. Dramatic reduction in the HOMO–LUMO gap with tunable electronic, spectral and electrochemical redox potentials were observed as the number of electron withdrawing groups increased.

Probing of chain conformations in conjugated polymer nanoparticles by electron spin resonance spectroscopy

Direct observation of individual conjugated polymer chain conformations in nanoparticles by ESR distance measurements.

A comparative study of optical nonlinearities of trans-A2B-corroles in solution and in aggregated state

The NLO properties of a series of FB corroles are studied in the solution as well as in the aggregated state (in the form of thin films).

Redox properties of nitrophenylporphyrins and electrosynthesis of nitrophenyl-linked Zn porphyrin dimers or arrays

Five nitrophenylporphyrins were investigated as to their electrochemical properties in CH 2 Cl 2 containing 0.1 M TBAP. The investigated compounds are represented as ( NO 2 Ph )x Ph 4-x PorM , where Por represents the dianion of the porphyrin macrocycle, Ph is a phenyl group on meso-position of the macrocycle, NO 2 Ph is a meso-substituted nitrophenyl group, M = 2 H , Pd II or Zn II and x = 1 or 2. Each porphyrin undergoes an initial one electron reduction at E1/2 = -1.07 to -1.12 V where the added negative charge is almost totally localized on the meso-nitrophenyl group of the compound. This reversible reduction is then followed by one or more irreversible reductions of the nitrophenyl anion at more negative potentials which overlap with reduction of the conjugated porphyrin macrocycle. The initial one electron addition was monitored by thin-layer UV-vis spectroelectrochemistry which confirmed formation of a reduced nitrophenyl group in each case but also gave spectral evidence for a linkage of the one-electron reduction products in the case of the Zn derivatives, giving Zn porphyrin dimers or arrays which are characterized by a 14–15 nm red-shifted Soret band and two well-defined Q-bands, consistent with conversion from an unreduced four coordinate Zn II nitrophenylporphyrin to a five-coordinate Zn II complex with an unreduced porphyrin macrocycle.

Post-synthetic modification of hangman porphyrins synthesized on the gram scale

We report a multi-gram scale synthesis of methyl 6-formyl-4-dibenzofurancarboxylate and its subsequent use in the gram scale synthesis of a dibenzofuran-functionalized hangman porphyrin containing a pendant carboxylic acid (HPD-CO2H). HPD-CO2H can be isolated as a free carboxylic acid in high purity with minimal purification. Post-synthetic modification of HPD-CO2H allows for the introduction of any desired pendant group in good yields, resulting in a practical amount of hangman porphyrin ligand with an easily customizable second coordination sphere. The cobalt complexes of these hangman porphyrins are shown to be active proton reduction electrocatalysts.

Ligand engineering of polymer nanocomposites: from the simple to the complex

One key to optimizing the performance of polymer nanocomposites for high-tech applications is surface ligand engineering of the nanofiller, which has been used to either tune the nanofiller morphology or introduce additional functionalities. Ligand engineering can be relatively simple such as a single population of short molecules on the nanoparticle surface designed for matrix compatibility. It can also have complexity that includes bimodal (or multimodal) populations of ligands that enable relatively independent control of enthalpic and entropic interactions between the nanofiller and matrix as well as introduce additional functionality and dynamic control. In this Spotlight on Applications, we provide a brief review into the use of brush ligands to tune the thermodynamic interactions between nanofiller and matrix and then focus on the potential for surface ligand engineering to create exciting nanocomposites properties for optoelectronic and dielectric applications.

The importance of various anchoring groups attached on porphyrins as potential dyes for DSSC applications

The influence of different anchoring groups in the efficiency of porphyrin dye sensitized solar cells.

Facile synthesis and enhanced nonlinear optical properties of porphyrin-functionalized multi-walled carbon nanotubes

Two multi-walled carbon nanotube (MWCNT)-based nanohybrids, MWCNT-ZnTPP and MWCNT-TPP (TPP=5-[4-{2-(4-formylphenoxy)- ethyloxy}phenyl]-10,15,20-triphenylporphyrin, ZnTPP=5-[4-{(4-formylphenyl)ethynyl}phenyl]-10,15,20-triphenylporphinatozinc(II)), were prepared directly from pristine MWCNTs through 1,3-dipolar cycloaddition reactions. Covalent attachment of the porphyrins to the surfaces of the MWCNTs was confirmed by Fourier transform infrared spectroscopy, ultraviolet/visible absorption, fluorescence, Raman, and X-ray photoelectron spectroscopy, elemental analysis, transmission electron microscopy, and thermogravimetric analysis. Attachment of the porphyrin moieties to the surface of the MWCNTs significantly improves the solubility and ease of processing of these MWCNT-porphyrin composite materials. Z-scan studies reveal that these MWCNT-porphyrin nanohybrids exhibit enhanced nonlinear optical properties under both nanosecond and picosecond laser pulses at λ=532 nm in comparison with free MWCNTs and the free porphyrin chromophores, whereas superior optical limiting performance was displayed by MWCNT-porphyrin composite materials rather than MWCNTs/ZnTPP and MWCNTs/TPP blends, which is consistent with a remarkable accumulation effect as a result of the covalent linkage between the porphyrin and the MWCNTs.

Porphyrin-sensitized solar cells: effect of carboxyl anchor group orientation on the cell performance

The effect of the orientation of the porphyrin sensitizer onto the TiO2 surface on the performance of dye-sensitized solar cells (DSSCs) is reported. Free-base and zinc porphyrins bearing a carboxyl anchoring group at the para, meta, or ortho positions of one of the meso-phenyl rings were synthesized for application in Grätzel-type photoelectrochemical cells. The remainder of the meso-phenyl rings was substituted with alkyl chains of different length to visualize any aggregation effects. Absorption and fluorescence studies were performed to characterize and observe spectral coverage of the thirteen newly synthesized porphyrin derivatives. Photoelectrochemical studies were performed after immobilization of porphyrins onto nanocrystalline TiO2 and compared with DSSC constructed using N719 dye as reference. The performance of DSSCs with the porphyrin anchoring at the para or meta position were found to greatly exceed those with the anchoring group in the ortho position. Additionally, cells constructed using zinc porphyrin derivatives outperformed the free-base porphyrin analogs. Better dye regeneration efficiency for the zinc porphyrin derivatives compared to their free-base porphyrin analogs, and for the meta and para derivatives over the ortho derivatives was evaluated from electrochemical impedance spectroscopy studies. Femtosecond transient absorption spectroscopy studies were performed to probe the kinetics of charge injection and charge recombination with respect to the orientation of porphyrin macrocycle on TiO2 surface. The ortho porphyrin derivative with an almost flat orientation to the TiO2 surface revealed fast charge recombination and suggested occurrence of through-space charge transfer. The overall structure-performance trends observed for the present porphyrin DSSCs have been rationalized based on spectral, electrochemical, electrochemical impedance spectroscopy, and transient spectroscopy results.

Triarylamine-substituted imidazole- and quinoxaline-fused push-pull porphyrins for dye-sensitized solar cells

We have prepared a push-pull porphyrin with an electron-donating triarylamino group at the β,β'-edge through a fused imidazole group and an electron-withdrawing carboxyquinoxalino anchoring group at the opposite β,β'-edge (ZnPQI) and evaluated the effects of the push-pull structure of ZnPQI on optical, electrochemical, and photovoltaic properties. ZnPQI showed red-shifted Soret and Q bands relative to a reference porphyrin with only an electron-withdrawing group (ZnPQ), thus demonstrating the improved light-harvesting property of ZnPQI. The optical HOMO-LUMO gap was consistent with that estimated by DFT calculations. The ZnPQI-sensitized solar cell exhibited a relatively high power conversion efficiency (η) of 6.8 %, which is larger than that of the ZnPQ-sensitized solar cell (η=6.3 %) under optimized conditions. The short-circuit current and fill factor of the ZnPQI-sensitized solar cell are larger than those of the ZnPQ-sensitized solar cell, whereas the open circuit potential of the ZnPQI-sensitized cell is smaller than that of the ZnPQ-sensitized cell, leading to an overall improved cell performance of ZnPQI. Such fundamental information provides a new tool for the rational molecular design of highly efficient dye-sensitized solar cells based on push-pull porphyrins.