An oligo(phenylenevinylene) bridged intramolecular charge-transfer (ICT) compound, (TCNQ)2OPV3, has been synthesized and its third- and fifth-order nonlinear optical refraction indexes have been determined by measurement with the 4f system with a phase-object, under near-infrared excitation.

The development of efficient catalysts with a visible-light response is of great importance in photocatalysis. Porphyrinic metal-organic frameworks (porph-MOFs) have recently been shown as promising photocatalyst candidates due to their large surface area, high visible light harvesting efficiency, and semiconductive properties, but challenges still remain because of their rapid charge recombination. Herein, we report the design of an effectively visible-light-driven composite material, namely TP-222(Zn), containing zirconium-based porph-MOF PCN-222(Zn) linked TiO2 nanoparticles (NPs) via the compound 4-mercaptopyridine which is axially bonded to the porphyrin central Zn metal in the PCN-222(Zn) and anchored onto the surface of TiO2 NPs. The resulting composite material demonstrates the high dispersion of TiO2 NPs and their close contact with the porph-MOF matrix, and serves as an effective photocatalyst for degrading organic contaminants under visible light irradiation due to their synergistic effect. It is further confirmed by fluorescence spectroscopy and electrochemical impedance spectroscopy that the remarkably enhanced photocatalytic activity of the TP-222(Zn) composite is attributed to the efficient charge separation with electron injection from PCN-222(Zn) to TiO2 NPs. In addition, the TP-222(Zn) composite shows excellent stability and recyclability as a result of the axially coordinative interaction between TiO2 NPs/PCN-222(Zn) and the 4-mercaptopyridine. Overall, this work provides a new strategy for the fabrication of highly efficient porph-MOF-based composite materials for visible light-driven photocatalysis.

The performance of dye-sensitized solar cells (DSSCs) consisting of anatase TiO2 nanoparticles that were synthesized via a hydrothermal method was studied. The synthesized TiO2 nanoparticles were characterized by X-ray diffraction (XRD), nitrogen sorption analysis, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and UV–vis spectroscopy. Then the J-V curve, electrochemical impedance spectroscopy (EIS), and open-circuit voltage decay (OCVD) measurement were applied to evaluate the photovoltaic performance of DSSCs. Compared with the commercial TiO2 nanoparticles (P25), the synthesized-TiO2 nanoparticles showed better performance. By adding diethylene glycol (DEG) before the hydrothermal process, the synthesized TiO2 nanoparticles (hereafter referred to as TiO2-DEG particles) shows narrower size distribution, larger specific surface area, higher crystallinity, and less surface defects than TiO2 (DEG free) particles. The analysis of photovoltaic properties of DSSCs based on TiO2-DEG particles showed that the recombination of electron-hole pairs was decreased and the trapping of carries in grain boundaries restrained. It was believed that the photoelectrode fabricated with the as-prepared TiO2 nanoparticles improved the loading amount of dye sensitizers (N719), and enhanced the photocurrent of the DSSCs. As a result, the TiO2-DEG particle based cells achieved a photo-to-electricity conversion efficiency (η) of 7.90%, which is higher than 7.53% for the cell based on TiO2 (DEG free) and 6.59% for the one fabricated with P25.Download high-res image (86KB)Download full-size imageThe TiO2-diethylene glycol (DEG) based dye-sensitized solar cells perform a noticeable improvement in the overall efficiency of maximum 7.90% which is higher than 7.53% for the cell made of TiO2 (DEG free) and 6.59% for the cell made of P25.

How to graft co-sensitizers with different binding strengths onto TiO2 surfaces for enhancing the performance of dye-sensitized solar cells (DSSCs) has not been discussed very much. Herein a ruthenium-based sensitizer (N719) and a porphyrin molecule (LP-2) with complementary absorption spectra (300–750 nm) have been chosen to investigate how the dye loading procedure would influence the photovoltaic performance of co-sensitized solar cells. Interestingly, it is found that 54.7% of the loading amounts of pre-adsorbed LP-2 are replaced by the post-adsorption of N719. The replacement adsorption is not observed when the two molecules are loaded in reverse order, which is attributed to their different adsorption configurations and binding energies. The competitive adsorption between co-sensitizers is thus systematically investigated by UV-visible absorption spectroscopy, energy dispersive spectrometry (EDS) and electron probe microanalysis (EPMA). Upon optimization, the device sequentially sensitized with LP-2 and N719 exhibits efficiency (7.72%) enhancement of 38.6% and 18.0% compared with those fabricated with single LP-2 and N719, respectively. The results provide a new vision on the stepwise sensitization of TiO2 films using co-sensitizers with a difference in adsorption properties, suggesting that complementary spectral absorption of co-sensitizers can lead to excellent cell performance by choosing an appropriate dye loading procedure.

The efficiency of perovskite solar cells based on mesoscopic TiO2 has been soaring over the past three years and is expected to reach over 25% by engineering the composition of perovskite and interface layers. Efforts to increase the power conversion efficiency (PCE) of planar junction perovskite solar cells have been made from different perspectives. For the first time, we use the wormhole-like hexagonal mesoporous silica (HMS) to modify the substrate surface inside the planar junction perovskite solar cell to improve efficiency. The formed random islands of HMS decreased the loading of the perovskite layer, leading to abnormal growth of perovskite and increased light path length. Using HMS islands in a planar heterojunction device, we realized an average PCE of 17.6% over 30 devices, which is higher than that of the controlled intrinsic planar heterojunction device (15.85%).

The sintered TiO2 nanofilms were immersed in the aqueous solution of graphite oxide and then were thermally reduced to reduced graphene oxide (RGO), resulting in RGO-doped TiO2 photoanodes employed in the dye-sensitized solar cells (DSSCs). This preparation method for the reduced graphene oxide–TiO2 (RGO–TiO2) photoanode could avoid the loss of RGO during the sintering process. The presence of RGO in the photoanodes was confirmed using Raman analysis, scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectrometer. The amount of RGO in photoanode was obtained by thermo-gravimetric analysis. Other techniques such as X-ray diffraction, Brunauer–Emmett–Teller, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the composite materials of RGO–TiO2. The J–V measurement of RGO–TiO2-based DSSCs showed that the best photoelectric conversion efficiency (η) of 6.85% is 11.7% higher than that of the pure TiO2 (P25–TiO2)-based DSSCs. It was shown that RGO in the photoanode could facilitate the phase transition in TiO2 crystals (from anatase to rutile) resulting in the mixed crystals in the photoanodes. The existence of RGO and mixed-crystal structure of TiO2 changed the electronic transmission pathway, reduced the recombination rate of electron–hole pairs, and thus improved the η of DSSCs.

•Two novel β-functionalized D-A-π-A porphyrins are designed and synthesized.•Introduction of additional acceptors in sensitizers influence the optoelectronic properties.•A more electron-withdrawing acceptor is optimal for the enhancement of cell efficiency.The β-functionalized porphyrin containing an additional electron-withdrawing unit, 2,3-diphenylquinoxaline(DPQ) for LP-5 or 2,1,3-benzothiadiazole (BTD) for LP-6 with different electron-withdrawing abilities, between the porphyrin core and the anchoring group and the reference porphyrin dye (LP-4) have been designed and synthesized for DSCs. The influence of the additional electron-withdrawing units on molecular properties as well as photovoltaic performance of the corresponding DSCs was investigated systematically. Compared with LP-4, the introduction of additional electron-deficient unit at the porphyrin β π-linker in LP-5 and LP-6 decreases the lowest unoccupied molecular orbital (LUMO) energy levels, resulting in the broader absorption spectra and significantly improved IPCE spectra in the region 350–500 nm, which ensures the better light-harvesting properties and the higher short-circuit current density (Jsc). On the other hand, the introduction of additional acceptors of LP-5 and LP-6 induces dye aggregation and reduces the lifetime of the charge–separated states, which decreases the open–circuit voltage (Voc). Interestingly, the loss in Voc is overcompensated by the improvement in Jsc. The study provides not only an alternative approach to design novel porphyrin sensitizers, but also an insight into how to manipulate the LUMO energy levels of porphyrin sensitizers via the β-linker modifications for the optimal photovoltaic applications.

Based on gluconic acid acetal and terpyridyl groups, we have prepared two new supramolecular gelators C3S and C6S with the critical gelation concentrations of 0.1% in aryl halides and the ability of gelling in DMF/DMSO + H2O at room temperature. The excellent self-healing properties of the gels were studied using rheological experiments. Based on the 1H NMR, IR spectrum and PXRD, the self-assembly pattern of C6S was proposed through theoretical calculation. After coordinating with Ln(III) metal ions, the multicolor luminescent metallogel C6S–Eu/Tb was investigated. The luminescence properties of the gels were characterized by fluorescence spectroscopy and fluorescence lifetime measurements, confirming the energy transfer between the organic compounds and Ln(III) metal ions.

Interfacial engineering of the meso-TiO2 surface through a modified sequential deposition procedure involving a novel PbI2–HMPA complex pretreatment is conducted as a reproducible method for preparing MAPbI3 based perovskite solar cells providing the highest efficiencies yet reported with the polymer HTM layer. Grazing-incidence X-ray diffraction depth profiling confirms the formation of a perovskite film with a PbI2-rich region close to the electron transport layer (ETL) due to the strong interaction of HMPA with PbI2, which successfully retarded the dissolution of the PbI2 phase when depositing the perovskite layer on top. These results are further confirmed by energy-dispersive X-ray spectroscopy performed in a scanning transmission electron microscope, which reveals that the I/Pb ratio in samples treated with the complex is indeed reduced in the vicinity of the ETL contact when compared to samples without the treatment. The engineered interface leads to an average power conversion efficiency of 19.2% (reverse scan, standard deviation SD < 0.2) over 30 cells (best cell at 19.5% with high FF of 0.80).

•Hydrophobic alkoxy chains in porphyrin influence the solar energy conversion efficiency.•Incorporation of long alkoxy chain is an efficient method to suppress dye aggregation.•The long alkoxy chain can also retard the charge recombination.•The longer length of the alkoxy chain, the smaller amount of dyes absorbed on TiO2.A series of novel zinc porphyrin dyes which are featured with a D–π–A structure have been designed and synthesized for use in dye-sensitized solar cells (DSSCs). The influences of different hydrophobic hydrocarbon chains (none, butoxy, octoxy groups) attached at the porphyrin meso-aryl group on the molecules’ photophysical and electrochemical properties, as well as on the photovoltaic performance of the corresponding DSSCs were investigated systematically. The best performance was realized for the cell sensitized with the porphyrin (LP-2) containing a n-butoxy chain on the meso-aryl group and with the acrylic acid as the acceptor. The optimized power conversion efficiency of LP-2 reaches 6.04% with an open-circuit voltage of 730 mV, a short-circuit current density of 11.67 mA cm−2, and a fill factor of 0.71.

•Four boron dipyrromethene (BODIPY) type sensitizers were synthesized.•The BODIPY sensitizers contain triarylamine donors with different rigidities.•These BODIY dyes were applied in dye-sensitized solar cells (DSSCs).•The fluorescence quantum yield and lifetime influenced the cell performance.•The fluorescence quantum yield and lifetime related to molecules' rigidities.Four donor-π bridge-acceptor structured boron dipyrromethene type sensitizers bearing triarylamine donors with different rigidities were synthesized and applied in dye-sensitized solar cells. The influence of different triarylamine donors on the optical, electrochemical properties and photovoltaic performances of sensitizers was systematically investigated. It was shown that the photovoltaic performance of boron dipyrromethene type sensitizer-based cell increased with increasing the fluorescence quantum yield and fluorescence lifetime of the corresponding sensitizers, which are believed to be closely related to the rigidities of the donor groups in the molecule. The best performance was realized for the cell based on rigid 9-phenyl-carbazole-substituted boron dipyrromethene sensitizer (ZH-b) with a fluorescence quantum yield of 0.516 and a fluorescence lifetime of 4.02 ns, resulting in a short circuit photocurrent density of 14.10 mA/cm2 and an overall conversion efficiency of 4.42%, which are fairly good results achieved for boron dipyrromethene type sensitizer-based solar cell.

•The stable 3H-pyrrolizine fused diazaborepin have designed and synthesized.•The structure of 3H-pyrrolizine fused diazaborepin was a saddle shape backbone.•Under piperidinium acetate, ‘naked’ diazaborepin was achieved in one step.We have designed and synthesized the original example of stable 3H-pyrrolizine fused diazaborepin using boron–amine (B–N) chemistry. 3H-Pyrrolizine fused ‘naked’ diazaborepin was achieved by organocatalyst (piperidinium acetate) in modest yield. The structure of diazaborepin was a twisted backbone in saddle shape with torsion angels of more than 20° from its crystal and theoretical data. It had a larger stokes shift (>70 nm) than classical BODIPYs and the type of solvent had an effect on their fluorescence property.

With urea as nitrogen source, N-doped TiO2 powders were synthesized and fabricated for low-temperature dye-sensitized solar cells (DSSCs) by the method of doctor-blade, and the highest temperature of the whole process was 120 °C. SEM, TEM, XRD, DRS, and XPS were used to analyze the microstructure of the N-doped TiO2 powders. EIS, Bode plot, UV–Vis and I–V were employed to measure the photovoltaic performance of the DSSCs. The maximum photoelectric conversion efficiency (η) was 5.18 % when the amount of the doped nitrogen was 4 %, and, when compared with the η of 4.22 % for pure TiO2, the short circuit current was increased by 22.2 % and the efficiency was increased by 22.7 %. It has been shown that the doped nitrogen could effectively suppress TiO2 crystal phase transition from anatase to rutile, and decrease the size of particles. Therefore, the increased photoelectric conversion efficiency of the N-doped TiO2-based DSSC was ascribed to the more suitable crystal phase, sizes and inner structure.

A new lactam acceptor unit, [7,7′-bidithieno[3,2-b:2′,3′-d]pyridine]-5,5′(4H,4′H)-dione (BDTP), was developed. A D–A copolymer PThBDTP using BDTP as the acceptor unit and thiophene as the donor unit was synthesized. PThBDTP:PC71BM solar cells gave a decent PCE of 9.13% with a Voc of 0.96 V. PThBDTP is one of the few D–A copolymers with PCEs of over 9%.

•Different diarylamino substituents have different electron donating abilities.•The porphyrin meso diarylamino substituent has a significant influence on the overall solar energy conversion efficiency.•Fukui function has been employed to evaluate nucleophilicities and electron-donating abilities of amino nitrogen.A series of novel zinc porphyrins which are featured with a donor–π–acceptor structure have been synthesized for use in the dye-sensitized solar cells. Various diarylamine moiety, such as diphenylamine, iminodibenzyl or iminostilbene, is introduced at porphyrin meso position as an electron donating group. The cell fabricated with the iminodibenzyl-substituted porphyrin sensitizer yields a short circuit photocurrent density of 9.68 mA/cm2, an open-circuit voltage of 740 mV, and a fill factor of 73.48%, corresponding to an overall conversion efficiency (η) up to 5.26%, which is greater than those obtained by diphenylamine- and iminostilbene-substituted porphyrin-sensitized solar cells (η = 4.05% and 2.62%, respectively). The theoretical studies reveal that the iminodibenzyl donor has the strongest electron donating ability among all three diarylamine substituents employed, which is believed to play a significant role in influencing the photovoltaic properties of these sensitizer-based solar cells.

A series of D–π–A zinc porphyrin sensitizers Dye1–Dye6 bearing a substituted iminodibenzyl group at the porphyrin meso position, which is expected to have different electron-donating abilities, were designed. Theoretical studies were performed to examine the photovoltaic properties of these molecules in dye-sensitized solar cells (DSSCs). In particular, the important concepts, the Fukui function and the extended condensed Fukui function, are employed to describe the electron-donating abilities accurately at the quantitative level. Tangui Le Bahers model was adopted to analyze charge transfer (CT) during electron transition. A correlation between the electron donating abilities of the derived iminodibenzyl group and CT was built to evaluate the cell performance based on sensitizers Dye1–Dye6. The theoretical studies showed that porphyrins Dye1–Dye3 bearing an extremely strong electron-donating group (EDG) would fail in the generation of photocurrent in the closed circuit when applied in DSSCs due to the higher level of the HOMO energy than the redox potential of the redox couple (I−/I3−). The one with a weaker EDG (Dye4) is expected to show better photovoltaic performance than porphyrin IDB with an unsubstituted iminodibenzyl group. This study demonstrates a reliable method involving the employment of the Fukui function, the extended condensed Fukui function and the Tangui Le Bahers model for the evaluation of newly designed D–π–A type porphyrin sensitizers for use in DSSCs, and as guidance for future molecular design.

Three-dimensional (3D) ZnO nanoaggregates with different morphologies and sizes were fabricated by the hydrothermal method, including cauliflower-like microspheres with an average diameter of 1–2 μm, nano-sheet aggregated safflower-like microspheres with 3–4 μm and ixora-like nano-structures with 500–600 nm. We found that their morphology formation was dependent on the concentration of OH− and construction agent (glutamic acid) during the synthesis process, based on which we proposed the mechanism for the formation of ZnO nanoaggregates. The studies showed that, the photo to current conversion efficiencies (PCEs) of the dye-sensitized solar cells (DSSCs) in which the photoanodes were fabricated using the prepared 3D ZnO nanoaggregates were all higher than those obtained employing the ZnO nanoparticles (NPs). In particular, the PCE of the DSSC based on the cauliflower-like ZnO photoanode (4.52%) was about 21% higher than that fabricated with the ZnO NP-based photoanode. This can be attributed to the higher specific surface area of the cauliflower-like ZnO photoanode leading to a greater amount of dye adsorption, more suitable size for light scattering and better inner connection for the transportation of electrons. Moreover, when these 3D ZnO nanoaggregates were used as the scattering layers in the P25-based photoanode in DSSCs, higher PCE of up to 6.74% was achieved, compared to 5.37% obtained for the DSSC without a scattering layer.

The shapes and properties of self-assembled materials can be adjusted easily using environmental stimuli. Yet, the stimulus-triggered shape evolution of organic microspheres in aqueous solution has rarely been reported so far. Here, a novel type of poly(allylamine hydrochloride)-g-porphyrin microspheres (PAH-g-Por MPs) was prepared by a Schiff base reaction between 2-formyl-5,10,15,20-tetraphenylporphyrin (Por-CHO) and PAH doped in 3.5-μm CaCO3 microparticles, followed by template removal. The PAH-g-Por MPs had an average diameter of 2.5 μm and could be transformed into one-dimensional nanorods (NRs) and wormlike nanostructures (WSs) after being incubated for different times in pH 1–4 HCl solutions. The rate and degree of hydrolysis had a significant effect on the formation and morphologies of the nanorods. The NRs@pH1, NRs@pH2, and NRs@pH3 were all composed of the released Por-CHO and the unhydrolyzed PAH-g-Por because of the incomplete hydrolysis of the Schiff base. However, the WSs@pH4 were formed by a pure physical shape transformation, because they had the same composition as the PAH-g-Por MPs and the Schiff base bonds were not hydrolyzed. The self-assembled NRs and WSs exhibited good colloidal stability and could emit stable red fluorescence over a relatively long period of time.

Several mesoporous TiO2 (MT) materials were synthesized under different conditions following a hydrothermal procedure using poly(ethylene-glycol)-block-poly(propylene-glycol)-block-poly(ethylene-glycol) (P123) as the template and titanium isopropoxide as the titanium source. The molar ratios of Ti/P123, and the pH values of the reaction solution in an autoclave were investigated. Various techniques such as Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), laser Raman spectrometry (LRS), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) were used to characterize the products. Then, these materials were assembled into dye-sensitized solar cells (DSSCs). Analysis of the J–V curves and electrochemical impedance spectroscopy (EIS) were applied to characterize the cells. The results indicated that the specific surface area and crystalline structure of these materials provide the possibility of high photocurrent for the cells, and that the structural characteristics of the specimens led to increased electron transfer resistance of the cells, which was beneficial for the improvement of the photovoltage of the DSSCs. The highest photoelectric conversion efficiency of the cells involving MT materials reached 8.33%, which, compared with that of P25-based solar cell (5.88%), increased by 41.7%.

A novel doubly N-confused isophlorin (2) was prepared by the nucleophilic ring-opening reaction of N-confused, N-fused porphyrin (1) with benzenethiol. The structure, redox property and copper coordination ability of isophlorin 2 were investigated by various spectroscopic methods and theoretical calculations.

•Polystyrene (PS) microspheres were used to fabricate films with different pore sizes.•Flims with different pore sizes were obtained by burning out varying amount of PS.•The photoelectrode with appropriate pore size had optimum performance.•A hierarchical TiO2 photoelectrode with pore size gradually increasing was prepared.•The hierarchical TiO2 photoelectrode had best photoelectric conversion efficiency.The TiO2 photoelectrode containing pores of different sizes was fabricated by adding various amounts of polystyrene microspheres (188 nm) into the TiO2 paste, which was used as template agent during the sintering process. On the one hand, it was found that the photoelectrode with appropriate size of pores was beneficial for the enhancement of photovoltaic performance of the corresponding dye-sensitized solar cells (DSSCs) via efficient utilization of incident light. On the other hand, the presence of large pores would also tend to reduce the amount of dye-uptake resulting in the decrease of cell performance. Furthermore, a multi-layered stacking architecture of TiO2 nanoporous film with pore size gradually increased from bottom FTO glass to the top of the film was developed and used as photoelectrode in DSSCs with N719 as the sensitizer. The photoelectric conversion efficiency of 7.80% was realized which is 17.6% higher than that obtained for DSSCs containing TiO2 nanoporous films with uniform size of pores. UV–vis spectra measurement and electrochemical impedance spectroscopy analysis were carried out for further studying the effect of the pore size and the stacking pattern on the photoelctronic and electrochemical properties of the resultant DSSCs.

Three corrole–fullerene dyads were prepared by treating anthracene-functionalized corroles with fullerene. Their structures were characterized by 1D- and 2D-NMR spectra and mass spectra. In the preliminary photo physical study of 3a by fluorescence spectroscopy, the excited corrole unit was quenched due to the introduction of fullerene. TD-DFT calculation theoretically indicated that the electron transfer occurs from the excited corrole to fullerene.

•Yellow particles coated with polyethylene (PE) and polystyrene (PS) were prepared.•Yellow and white particles were dispersed in a mixed dielectric solvent.•A chromatic display cell consisting of yellow particles was successfully fabricated.•The greatest contrast ratio of 1.48 was realized, as well as a response time of 2 s.C.I. Pigment Yellow 181 (PY181) composite particles encapsulated by polyethylene (PE) were prepared by dispersion polymerization method, and C.I. Pigment Yellow 110 (PY110) composite particles encapsulated by polystyrene (PS) with mini-emulsion polymerization method were achieved, respectively. The modified pigments were characterized by fourier transform infrared spectroscopy, scanning electron microscope and transmission electron microscope. Compared with the PE-coated PY 181 pigments, the PS-coated PY-110 particles had a narrow particle size distribution, regular spherical and average particle size of 450 nm. Suspension 1 and suspension 3 were prepared by the two composite particles dispersed in isopar M. A chromatic electrophoretic display cell consisting of yellow particles was successfully fabricated using dispersions of yellow ink particles in a mixed dielectric solvent with white particles as contrast. The response behavior and the contrast ratio to the electric voltage were also examined. The contrast ratio of pigments modified by polystyrene was 1.48, as well as the response time was 2 s, which were better than those of pigments modified by polyethylene.

A series of meso-ferrocenyl-porphyrin dyads linked by four different π-conjugated bridging units (directly bound, vinyl, ethynyl, and phenyl) have been synthesized to investigate the influence of the conjugated linker on both the electronic and photochemical properties of the porphyrin chromophore. The basic structure consists of 5-(Fc)-15-(4-methylbenzoate)-10,20-diphenylporphyrin zinc(II), where Fc = ferrocene, vinylferrocene, ethynylferrocene, or phenylferrocene. Upon introduction of the various electron-donating ferrocenyl moieties at the meso-position of the porphyrin ring, Soret and Q-band electronic transitions of the resultant dyads are red-shifted compared with those of the nonferrocenyl reference porphyrin system 15-(4-methylbenzoate)-10,20-diphenylporphyrin zinc(II). The electronic properties of these systems have been investigated by electrochemical (cyclic voltammetry) and computational (DFT/TDDFT) methods, while UV/vis absorption and fluorescence emission spectroscopic analysis is also presented. Collectively, electronic and photophysical analysis indicate a strong electronic communication between the porphyrin macrocycle and directly bound ferrocenyl, vinylferrocenyl, and ethynylferrocenyl dyads. The presence of a phenyl spacer acts to inhibit such electronic communication due to the orthogonal geometry of the bridging phenyl ring at the meso-position of the porphyrin macrocycle. In addition to electronic factors, and in particular for the directly bound 5-(ferrocenyl)-15-(4-methylbenzoate)-10,20-diphenylporphyrin zinc(II) dyad, computational analysis suggests that a significant ruffling of the porphyrin macrocyle from planarity is required to facilitate the bulky ferrocene group directly at the meso-position. Of particular note for each of the meso-ferrocenyl-porphyrin dyads is how fluorescence emission derived from the porphyrin S1 (π–π*) excited state is quantitatively quenched due to photoinduced charge-transfer from the ferrocene unit onto the excited state porphyrin. Spectroelectrochemical studies demonstrate redox off/on switching of the porphyrin fluorescence emission via ferricenium/ferrocene redox cycling. Interestingly, it was found that the S0 ← S1 fluorescence emission is also switched-on following titration with the metal ions Ce(IV), Cu(II), and Fe(III) in acetonitrile.

Four artificial chlorin-type sensitizers have been prepared and their photovoltaic performance in dye-sensitized solar cells has been evaluated. It was found that the photovoltaic performance increased with growing absorption intensity of the Q band in a TiO2 film. This result indicates the contribution of intrinsic enhanced absorption properties of chlorins in the Q band regions on the improvement of the overall photovoltaic performance in DSSCs. On the other hand, their capability of solar energy conversion also exhibits close relationship with the geometry of the four sensitizers, in which the orientation of a sterically demanding 2,6-dichlorophenyl group towards either the 5- or 15-position (the anchor group is at the 20-position) gives higher solar energy-to-electricity conversion efficiency.Graphical AbstractHighlights► Four chlorin-type sensitizers have been prepared by dipolar cycloaddition strategy. ► The Q-band absorption of sensitizers exhibit red shift and higher molar absorptivity. ► Their photovoltaic performance depends highly on the Q-band absorption on TiO2 film. ► Their photovoltaic performance relates with the steric hindrance of anchoring group.

The use of Isopar M as a liquid suspending fluid for electrophoretic display was studied. The dispersion stability and chargeability of pigments suspended in Isopar M were investigated. Polyisobutylene monosuccinimide (T-151) as the charge control additive in Isopar M electrophoretic fluid can provide a good electrophoretic mobility to the particles. The wall materials of a series of blue–white, red–white and yellow–white dual-particle microcapsules were prepared by in situ polymerization of urea and formaldehyde. The mass ratio of wall/core material was a key factor in influencing the yield of microcapsules. The concentration of resorcinol has an impact on the surface morphology and mechanical strength of microcapsule wall. Microcapsules’ surface morphologies were characterized by optical microscopy and scanning electron microscopy. The performance of the microcapsules with different binder materials and adhesive layers were investigated. Contrast ratio of microcapsules display device were tested every 10 days for a period of 90 days. The compatibility of Isopar M with both the electrophoretic particles and bounding capsule was studied.Highlights► Isopar M was chosen as dispersion medium for electrophoretic dispaly. ► Microcapsules were prepared by in situ polymerization containing Isopar M fluid. ► An appropriate dosage of resorcinol can help to shape microcapsule. ► The contrast ratio of electrophoretic display device was improved. ► The electrophoretic display device prototype possesses a longer working life.

One new route for the synthesis of amino-substituted indazol-3,5-dione via the amidation reaction of o-carboxyazobenzenes is reported. Optimization which includes effects of the solvents, molar ratio of starting materials, and dehydrating agents on this reaction has been studied. A possible reaction mechanism has been proposed on the basis of the product’s structure, and the steric hindrance could be the main reason for low yield.

The surface modification of Pigment Yellow 13, Pigment Red 254 and Pigment Blue 15 to improve their electrophoretic properties in electrophoretic suspension were studied. The particle size distribution and the surface morphology of the modified pigments were determined, the presence of the functional groups on the surface of pigments was confirmed, and the dispersion stability and chargeability of pigments suspended in electrophoretic slurry were characterized. For the application of microencapsulated electrophoretic displays, the colored microcapsules containing the modified organic pigments were prepared and spread on an ITO coated conducting film. A working prototype of electrophoretic display was successfully fabricated in this approach.Highlights► Organic pigments were used in EPDs to obtain good color saturation. ► The modified organic pigments have good dispersion stability and chargeability. ► The color-white display prototypes were successfully fabricated.

A facile synthetic route of 5-formylporphyrin (2) has been developed. Using pyrrole and pivaldehyde as the starting materials, 2 was obtained through several facile reactions. The synthetic route is easy to perform and can be scaled up, which gives the compound a better application perspective.

One novel porphyrin P-Q2 is planned to be synthesized by condensation between ATPP and Q1. However, after separation by chromatography and characterization with IR, 1H NMR, HR-MS and X-ray, P-Q1 is obtained unexpectedly. Compared the structure of P-Q1 with that of P-Q2, it is realized that an intramolecular cyclization rearrangement takes place when the azo group is situated in the o-position to the amido group. This rearrangement offers a new way to prepare indazole heterocycle. In addition, the spectral properties of P-Q1 have been studied by UV–vis and steady state fluorescence spectroscopy. Strong fluorescence quenching is observed in the preliminary emission spectrum due to the proposed electron transfer from the excited porphyrin to the anthraquinone moieties.

A novel series of calix[4]azacrown derivatives with the reaction between calix[4]azacrown and the different fluorophore derivatives, which may be useful fluorescent receptors, have been synthesized and structurally characterized by IR, 1H NMR, 13C NMR and MS. From their analysis data, it was found those compounds adopted a cone conformation.

Yellow CdS/wax nanocomposite spheres were fabricated in an aqueous solution by an emulsion method, in which the CdS nanoparticles were adsorbed on the surface of a wax core with positive charge by electrostatic self-assembly. A thin shell of SiO2 was then coated to the yellow CdS/wax spheres by the hydrolysis of Na2SiO3 in the same aqueous solution to enhance the optical and mechanical properties and the charge load of the composite spheres. The product was characterized by transmission electron microscopy, scanning electron microscope, atomic force microscopy, thermogravimetric analysis, and X-ray powder diffraction, which showed that the SiO2 walls of spheres were compact and part of CdS crystals dispersed inside, the density of composite spheres being about 1.3 g/cm3, which match most of the suspensions. Fourier transform infrared spectroscopy, and energy dispersive X-ray spectrometry showed the component of composite spheres. Dynamic light scattering showed the diameter distribution of composite spheres was between 100∼400 nm. Zeta-potential measurement proved that the SiO2/CdS/wax spheres had a higher charge load, and Ultraviolet−visible spectra showed that the SiO2/CdS/wax spheres had a better optical property. Therefore, this type of composite spheres had the merits of low density and strong durability in environments. The response behavior of the microencapsulated electronic ink of the composite spheres has been measured. This novel method is expected to produce various inorganic/organic nanocomposite spheres with potential application in the fields of electronic paper and other material science.

Two novel fluorescent calix[4]arene derivatives 1a and 1b with benzoxazole or benzothiazole units in 1,3-alternate conformation have been synthesized and characterized by IR, 1H NMR, 13C NMR and MS. Their complexation properties to different heavy and transition metal ions have been studied by UV–vis spectroscopy and fluorescence spectrometer. Compounds 1a and 1b show selective recognition to Fe3+ and Cr3+.

A new method to prepare a kind of double layered microcapsules was developed. Polyurea (PU) microcapsules were firstly fabricated by interfacial polymerization as inner layer, on which urea-formaldehyde (UF) resin was coated to form a protective outer layer by in-situ polymerization. Environmental scanning electron microscope, optical image analyzer, Fourier transform infrared spectrophotometer and thermo gravimetric analysis were employed to investigate their characteristics for the morphologies, particle size, materials structures and thermal properties. The prepared double layered PU-UF microcapsules are mono-dispersed with ultra-thick capsule wall and improved thermal stability.

A kind of yellow–red microencapsulated electronic ink was prepared by interfacial polymerization. The shell of the polyurea (PU) microcapsules was fabricated from tolyene 2,4-diisocyanate (TDI) and triethylene tetraamine (TETA). Pigment Hansa Yellow 10G, as negatively charged electrophoretic particles, was homodispersed in tetrachloroethylene (TCE)/cyclohexane mixture to make the suspending fluid core. And Oil Red was also added in the core to make a red background. Emulsifiers influencing the dispersing process were experimentally investigated. PU microcapsules were characterized on structure, mean particle size and size distribution, morphology with FT-IR, ESEM and image analyzer. The prepared microcapsules were regular, transparent, smooth and optically clear, and had a wall thickness of around 1.5 μm and an excellent sealing property. The electric response behaviors of the electronic ink were studied under electrostatic field. The yellow particles moved quickly and reversibly inside the microcapsules while the electric field alternated, with a response time of 150 ms approximately at E = 30 V/mm.

A convenient method for the synthesis of β-unsubstituted meso-aryl substituted tripyrranes was developed. Pyrrole condensed with aldehyde in acidic aqueous to produce tripyrranes selectively in moderate yield. The selectivity for tripyrranes depended on the electronic and steric properties of aldehyde, the stoichiometric molar ratio and concentrations of the starting materials. The title compounds were isolated and characterized by 1H NMR, 13C NMR and HR-MS analysis.

•D–A–π–A type dyes with benzoselenadiazole (BSD) auxiliary acceptor are synthesized.•Using phenyl as π spacer here and coadsorbent could help to improve cells' Jsc and Voc.•BSD proved to be a promising electron-withdrawing acceptor for D–A–π–A sensitizers.Three new D–A–π–A configuration organic dyes (LC-6, LC-7 and LC-8) based on triphenylamine as the electron donor, benzoselenadiazole (BSD) as the auxiliary acceptor, either thiophene or benzene as the π spacer and cyanoacetic acid as the anchoring group have been designed and synthesized for dye-sensitized solar cells (DSCs). Introduction of octyloxy chain on the triphenylamine unit was found to be able to redshift the absorption spectra and suppress the charge recombination. It was also found that using the benzene instead of thiophene as π spacers and using CDCA coadsorbent could help to improve the Jsc and Voc values of the cell. Under standard global AM 1.5 solar light conditions, a DSC employing a dye with a 1,4-phenylene unit with CDCA gave the best photovoltaic performance with a Jsc of 13.21 mA cm−2, a Voc of 734 mV, a FF of 0.69 and an overall PCE of 6.72%. These results suggest that the BSD unit can be a promising electron-withdrawing candidate in D–A–π–A type sensitizers for further exploration DSCs.

The efficiency of perovskite solar cells based on mesoscopic TiO2 has been soaring over the past three years and is expected to reach over 25% by engineering the composition of perovskite and interface layers. Efforts to increase the power conversion efficiency (PCE) of planar junction perovskite solar cells have been made from different perspectives. For the first time, we use the wormhole-like hexagonal mesoporous silica (HMS) to modify the substrate surface inside the planar junction perovskite solar cell to improve efficiency. The formed random islands of HMS decreased the loading of the perovskite layer, leading to abnormal growth of perovskite and increased light path length. Using HMS islands in a planar heterojunction device, we realized an average PCE of 17.6% over 30 devices, which is higher than that of the controlled intrinsic planar heterojunction device (15.85%).

A new lactam acceptor unit, [7,7′-bidithieno[3,2-b:2′,3′-d]pyridine]-5,5′(4H,4′H)-dione (BDTP), was developed. A D–A copolymer PThBDTP using BDTP as the acceptor unit and thiophene as the donor unit was synthesized. PThBDTP:PC71BM solar cells gave a decent PCE of 9.13% with a Voc of 0.96 V. PThBDTP is one of the few D–A copolymers with PCEs of over 9%.

A novel doubly N-confused isophlorin (2) was prepared by the nucleophilic ring-opening reaction of N-confused, N-fused porphyrin (1) with benzenethiol. The structure, redox property and copper coordination ability of isophlorin 2 were investigated by various spectroscopic methods and theoretical calculations.

The development of efficient catalysts with a visible-light response is of great importance in photocatalysis. Porphyrinic metal-organic frameworks (porph-MOFs) have recently been shown as promising photocatalyst candidates due to their large surface area, high visible light harvesting efficiency, and semiconductive properties, but challenges still remain because of their rapid charge recombination. Herein, we report the design of an effectively visible-light-driven composite material, namely TP-222(Zn), containing zirconium-based porph-MOF PCN-222(Zn) linked TiO2 nanoparticles (NPs) via the compound 4-mercaptopyridine which is axially bonded to the porphyrin central Zn metal in the PCN-222(Zn) and anchored onto the surface of TiO2 NPs. The resulting composite material demonstrates the high dispersion of TiO2 NPs and their close contact with the porph-MOF matrix, and serves as an effective photocatalyst for degrading organic contaminants under visible light irradiation due to their synergistic effect. It is further confirmed by fluorescence spectroscopy and electrochemical impedance spectroscopy that the remarkably enhanced photocatalytic activity of the TP-222(Zn) composite is attributed to the efficient charge separation with electron injection from PCN-222(Zn) to TiO2 NPs. In addition, the TP-222(Zn) composite shows excellent stability and recyclability as a result of the axially coordinative interaction between TiO2 NPs/PCN-222(Zn) and the 4-mercaptopyridine. Overall, this work provides a new strategy for the fabrication of highly efficient porph-MOF-based composite materials for visible light-driven photocatalysis.

A series of D–π–A zinc porphyrin sensitizers Dye1–Dye6 bearing a substituted iminodibenzyl group at the porphyrin meso position, which is expected to have different electron-donating abilities, were designed. Theoretical studies were performed to examine the photovoltaic properties of these molecules in dye-sensitized solar cells (DSSCs). In particular, the important concepts, the Fukui function and the extended condensed Fukui function, are employed to describe the electron-donating abilities accurately at the quantitative level. Tangui Le Bahers model was adopted to analyze charge transfer (CT) during electron transition. A correlation between the electron donating abilities of the derived iminodibenzyl group and CT was built to evaluate the cell performance based on sensitizers Dye1–Dye6. The theoretical studies showed that porphyrins Dye1–Dye3 bearing an extremely strong electron-donating group (EDG) would fail in the generation of photocurrent in the closed circuit when applied in DSSCs due to the higher level of the HOMO energy than the redox potential of the redox couple (I−/I3−). The one with a weaker EDG (Dye4) is expected to show better photovoltaic performance than porphyrin IDB with an unsubstituted iminodibenzyl group. This study demonstrates a reliable method involving the employment of the Fukui function, the extended condensed Fukui function and the Tangui Le Bahers model for the evaluation of newly designed D–π–A type porphyrin sensitizers for use in DSSCs, and as guidance for future molecular design.