Application In Dye-sensitized Solar Cells Research Articles

Co-exposed crystal facets optimizing photocatalytic activity and photosensitization ability: A case of facile, fast and scalable synthesis of BiOBr round nanosheets

BiOBr round nanosheets were obtained by a facile, fast and scalable synthesis methodology in ambient conditions. The as-prepared sheet-shaped three-dimensional nanostructured BiOBr exposes reactive {001} surface facets, as well as {110} and {200} lateral facets. The average diameter is only 80–100 nm, and the thickness ∼20 nm. BiOBr not only exhibits excellent photocatalytic activity in degradation of Bisphenol A, outperforming hydrothermally synthesized BiOBr and other important visible-light-responsive photocatalysts such as BiOI, Bi2WO6, BiVO4, P25, g-C3N4 or Cu2(OH)PO4, it also possesses extraordinary activity in degradation of photoexcited dye molecules. A high reactive {001} facets exposure is demonstrated beneficial for photocatalytic activity in degradation of Bisphenol A. At the same time, the exposure of {110} and {200} facets also benefits photo-excited dye degradation ability, which is likely related to favorable adsorption on sites associated with these facets. The co-exposed facets optimizing for multi-properties endow the easily obtained BiOBr nanocrystals potential application in dye-sensitized solar cells, light-emitting diodes, or optoelectronic devices. Also, we believe our finding improve the ability of creating advanced nanosized structures for multifunctional devices.

Experimental and theoretical studies of the influence of alkyl groups on the photovoltaic properties of (E)-6-((2, 3-dihydroxylnaphthalene)diazenyl)-1H-benzoisoquinoline-1,3-dione-based organic solar cell.

The manipulation of the active dye material for application in dye-sensitized solar cell (DSSC) using simple or bulky group substituents is necessary for improved dye performance. Herein, we carried out a combined experimental and theoretical studies of different alkylated novel reactive (E)-6-(2,3-dihydroxyl naphthalene diazinyl)-1H-benzoisoquinoline-1,3-dione azo-based dyes using spectral (FTIR, UV-visible, and NMR) analysis and electronic structure theory method based first principle density functional theory (DFT) calculations to investigate the molecular electronic properties, structural analysis, excitation behavior, and the theoretical potential application in photovoltaic cell. The synthesized azo dye (azoD) was theoretically modeled by varying the number of alkyl chains denoted as AzoD1, AzoD2, AzoD3, and AzoD4 to represent azo dyes having ten (10), twelve (12), fourteen (14), and sixteen (16) alkyl chain length respectively. From the natural bond orbital (NBO) analysis, the higher stabilization energies, 227.80 and 227.77kcal/mol respectively, recorded for AzoD1 and AzoD4 may be due to extra orbital contribution by π*(N21-N22) to π*C54-C56 31.19eV for AzoD1 and π*(N21-N22) → π*(C53-C55) 31.43eV AzoD4 confirming that chain length affected the orbital interaction of the molecules. The driving force (ΔGinject) of electron injection into the TiO2 surface (- 1.92 to - 1.93) shown in this study is indicative that alkylated azo dyes are good for improved DSSCs performance. Again, the open circuit voltage (Voc) of 1.090 (AzoD1), 1.092 (AzoD2), 1.093 (AzoD3), and 1.095 (AzoD4) are also evidence of the suitability of azo dyes as photosensitizers. All the spectroscopic analysis, FTIR, UV-visible, and NMR combined with theoretical calculations, provided accurate data for characterizing the titled azo dye compound and showed that it has good photophysical properties. The presence of alkyl groups and chain length promoted the stability of the dyes thereby making them suitable for application in DSSCs. Increase in chain length as well enhanced the electron injection into the conduction band of the semiconductor.

New designed push-pull organic dyes based on the conjugated π-spacers for application in dye-sensitized solar cells: a computational chemistry study

New designed push-pull organic dyes based on the conjugated π-spacers for application in dye-sensitized solar cells: a computational chemistry study

Synthesis of Novel Triphenylamine-Based Organic Dyes with Dual Anchors for Efficient Dye-Sensitized Solar Cells

A new series of metal-free organic dyes (SM1-5) with dual anchors are synthesized for application in dye-sensitized solar cells (DSSC). Here, a simple triphenylamine (TPA) moiety serves as the electron donor, while di-cyanoacrylamide and di-thiazolidine-5-one units serve as the electron acceptors and anchoring groups. To understand the effect of dye structure on the photovoltaic characteristics of DSSCs, the photophysical and electrochemical properties, as well as molecular geometries calculated from density functional theory (DFT), are used for dyes SM1-5. The extinction coefficients of the organic dyes SM1-5 are high (5.36–9.54 104 M−1 cm−1), indicating a high aptitude for light harvesting. The photovoltaic studies indicated that using dye SM4 as a sensitizer showed a power conversion efficiency (PCE) of 6.09% (JSC = 14.13 mA cm−2, VOC = 0.624 V, FF = 68.89%). Interestingly, SM4 showed the highest values of VOC among all dyes, including N-719, due to its maximum dye coverage on the TiO2 surface, enhancing charge recombination resistance in the sensitized cell. The good agreement between the theoretically and experimentally obtained data indicates that the energy functional and basis set employed in this study can be successfully utilized to predict new photosensitizers' absorption spectra with great precision before synthesis. Also, these results show that bi-anchoring molecules have a lot of potentials to improve the overall performance of dye-sensitized solar cells.

Synthesis of innovative triphenylamine-functionalized organic photosensitizers outperformed the benchmark dye N719 for high-efficiency dye-sensitized solar cells

Herein, we present a thorough photovoltaic investigation of four triphenylamine organic sensitizers with D–π–A configurations and compare their photovoltaic performances to the conventional ruthenium-based sensitizer N719. SFA-5–8 are synthesized and utilized as sensitizers for dye-sensitized solar cell (DSSC) applications. The effects of the donor unit (triphenylamine), π-conjugation bridge (thiophene ring), and various acceptors (phenylacetonitrile and 2-cyanoacetamide derivatives) were investigated. Moreover, this was asserted by profound calculations of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels, the molecular electrostatic potential (MEP), and natural bond orbital (NBO) that had been studied for the TPA-sensitizers. Theoretical density functional theory (DFT) was performed to study the distribution of electron density between donor and acceptor moieties. The sensitization by the absorption of sensitizers SFA-5–8 leads to an obvious enhancement in the visible light absorption (300–750 nm) as well as a higher photovoltaic efficiency in the range of (5.53–7.56%). Under optimized conditions, SFA-7 showed outstanding sensitization of nanocrystalline TiO2, resulting in enhancing the visible light absorption and upgrading the power conversion efficiency (PCE) to approximately 7.56% over that reported for the N719 (7.29%). Remarkably, SFA-7 outperformed N719 by 4% in the total conversion efficiency. Significantly, the superior performance of SFA-7 could be mainly ascribed to the higher short-circuit photocurrents (Jsc) in parallel with larger open-circuit voltages (Voc) and more importantly, the presence of different anchoring moieties that could enhance the ability to fill the gaps on the surface of the TiO2 semiconductor. That could be largely reflected in the overall enhancement in the device efficiency. Moreover, the theoretical electronic and photovoltaic properties of all studied sensitizers have been compared with experimental results. All the 2-cyanoacrylamide derivative sensitizers demonstrated robust photovoltaic performance.

Synthesis of novel MoWO4 with ZnO nanoflowers on multi-walled carbon nanotubes for counter electrode application in dye-sensitized solar cells

Novel MoWO4 with ZnO nanoflowers was synthesized on multi-walled carbon nanotubes (MW-Z@MWCNTs) through a simple hydrothermal method, and this unique structure was applied as a counter electrode (CE) for dye-sensitized solar cells (DSSC) for the first time. The synergetic effect of ZnO nanoflowers and MoWO4 on MWCNTs was systematically investigated by different techniques. The amount of MWCNTs was optimized to achieve the best DSSC performance. It was found that the 1.5% MW-Z@MWCNTs composite structure had the highest power conversion efficiency of 9.96%, which is greater than that of traditional Pt CE. Therefore, MW-Z@MWCNTs-based CE can be used to replace traditional Pt-based electrodes in the future.

1,2,4-Triazine-based Materials: Spectroscopic Investigation, DFT, NBO, and TD-DFT Calculations as Well As Dye-sensitized Solar Cells Applications

In this manuscript, we report four series for 1,2,4-triazine derivatives as dye-sensitized solar cells (DSSCs). Density functional theory (DFT) methods via utilizing Becke's three-parameter functional and LeeeYangeParr functional (B3LYP) level with 6-31G (d, p) basis set to investigate their modeling molecular structures. Optimized molecular structures for studied molecular structures are obtained using the DFT/B3LYP/6-31G (d, p) method. In addition, the time-dependant density functional theory (TD-DFT) is used to study the optoelectronic properties and absorption spectra using DFT/CAM-B3LYP/ 6-31G + + (d, p) level in the Gaussian 09 program. The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), energy gap (Eg), light harvest efficiency (LHE), and open-circuit voltage (Voc) of the studied molecular structures are calculated and illustrated. These properties indicate that these molecular modeling structures as good candidates for utilization in organic DSSCs.

Synthesis, characterization and theoretical studies of the photovoltaic properties of novel bifunctional reactive disperse dyes based on aminothiazole derivatives

This article comprises synthesis and characterization of two polyfunctional diazo reactive-disperse dyes with aminothiazole moiety for application in dye-sensitized solar cells (DSSC). The characterization techniques employed were Gas chromatography-mass spectrometry (GC-MS), Fourier-transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-vis), and Nuclear magnetic resonance (NMR) to determine the different functional groups, molecular connectivities and molecular weight of the various fragments of the synthesized dyes. Theoretical Density Functional Theory (DFT) and Time-Dependent TD-DFT calculations were performed using B3LYP/6-311+g(d,p). It can be observed that the HOMO energy levels of the respective dyes have lower values than I−/I3− redox couple level (around -4.80 eV) in the four different phases studied, which is crucial for the regeneration of the oxidized dye molecule and efficient charge separation. Furthermore, the HOMO-LUMO energy gaps of DYES F and S are within the range 2.38-5.40 eV, where all LUMO-CB of TiO2 energy gap values are sufficient for generating enough driving force for effective electron injection. The promising results of Light-harvesting efficiency (LHE) (values ranging from 0.81 to 0.89 except for DYE S in chloroform phase where it has an unusual value of 0.21) and Open-circuit voltage (VOC) values gotten compared with other organic, and natural sensitizers were due to the better interaction between the carboxyl and carbonyl groups of aryl azo molecule joined to the thiazolyl nucleus and the surface of TiO2 permeable film. DYE S exhibits the lowest band gap (2.374eV), which designates the highest chemical activity of the two dyes. Results from the quantum theory of atoms-in-molecules indicate that DYES F and S exhibit additional stability due to their relatively high H-bond interactions as well as certain additional intra-atomic bonds among the atoms of the investigated compounds. The outcome of the Natural bond orbital (NBO) analysis suggests that the strongest charge transfer occurs in DYE S as compared to DYE F. The types and modes of excitations for the first five excited states of the synthesized dyes were observed from the results of the hole-electron excitation analysis. First hyperpolarizability values of the dye F and dye S were determined to be 47.24 and 46.90 times the hyperpolarizability value of urea, demonstrating its excellent non-linear optical (NLO) response.

(Invited) Pi-Extended Porphyrins: Synthesis, Functionalization and Applications in Dye-Sensitized Solar Cells

pi-Extended porphyrins are of broad interest due to their unique combination of photophysical, optoelectronic, and physicochemical properties, and their potential applications in many areas ranging from biomedicine to organic electronics.1,2 In this talk, three series of beta-functionalized push-pull pi-extended porphyrins as sensitizers for dye-sensitized solar cells will be presented.3-5 Our studies show significant push-pull effects for these porphyrins. DFT calculations suggest that the inclusion of ethynylphenyl bridge between the donating group and the porphyrin core significantly segregate the frontier orbitals. It has also been found that dimethylaminophenyl group cause dye decomposition on solar cells. To solve the dye degradation problem, porphyrin dyes with tertiary arylamine groups serving as the donor groups were prepared. Our studies show that tertiary arylamine groups are able to stabilize the dyes adsorbed on the solar cells. Their photovoltaic performances were tested in dye-sensitized solar cells. In this talk, the synthesis and characterization of pentacene-fused (linearly conjugated) and pentaquinone-fused (cross-conjugated) porphyrin oligomers will also be presented.6 These pentacene-fused porphyrins are much more stable than their corresponding pentacene derivatives. The electronic absorption spectra and transit spectroscopy of these porphyrins indicate highly interactive multiple p-systems. The electronic and optical properties of these p-extended porphyrins were measured using UV-Vis spectroscopy, life-time and steady state fluorescence spectroscopy, and cyclic voltammetry. DFT calculations were also performed for these porphyrins.

Methods to Tune the Optical Response of Porous Photonic Crystal Structures

Photonic crystals are periodic dielectric structures which selectively tune the wavelengths of light propagating through the material1 2. The highly ordered, repeating structural lattice induces a photonic bandgap or stopband which inhibits or partially attenuates certain frequencies of light, similar to the electronic bandgap with forbidden energies present in semiconductor materials3. These forbidden frequencies are blocked in transmission and reflected from the material surface. The inherent sensitivity of this photonic response to repeating lattice size dimensions and the magnitude of the refractive index contrast between the constituent materials allows for tailored optical behaviour by adjusting the photonic crystal structural parameters or environment4 5.A range of interesting applications using both the photonic bandgap and material porosity have emerged, predicated on the ability to accurately forecast the wavelength position of the photonic response. Colorimetric sensors6 7, photocatalysts8 9 and solar cells10 are prime examples of these types of applications; the porosity of the photonic crystal facilitates greater material infiltration and reactions, while the photonic bandgap acts to enhance the optical component of the process. Critically, the use of these structures is tied to our ability to predict and interpret the signature optical response.Here, we examine several techniques which can be used modify the photonic bandgap/stopband for photonic crystal structures. For TiO2 and SnO2 inverse opal photonic crystals, we explore how solvent infiltration into the highly porous network red-shifts the observed photonic response. Using solvents with different refractive indices, we apply the shifted photonic stopband data to determine the fill fraction of solid material comprising the photonic crystal network. We also examine functionalization of artificial opal and inverse opal photonic crystals with metal films. We detail the emergence of a consistent photonic stopband blue-shift with increasing metal content and propose a reduction in the effective refractive index of the entire photonic crystal introduced by the specific properties of the metal film. Importantly, the effects investigated here are broadly applicable to a range of realistic operating conditions across many disciplines where an understanding of the photonic stopband is paramount to the application. References Yablonovitch, E., Inhibited Spontaneous Emission in Solid-State Physics and Electronics. Physical Review Letters 1987, 58 (20), 2059-2062.John, S., Strong localization of photons in certain disordered dielectric superlattices. Physical Review Letters 1987, 58 (23), 2486-2489.Joannopoulos, J. D.; Villeneuve, P. R.; Fan, S., Photonic crystals: putting a new twist on light. Nature 1997, 386 (6621), 143-149.Blanford, C. F.; Schroden, R. C.; Al-Daous, M.; Stein, A., Tuning Solvent-Dependent Color Changes of Three-Dimensionally Ordered Macroporous (3DOM) Materials Through Compositional and Geometric Modifications. Advanced Materials 2001, 13 (1), 26-29.Aguirre, C. I.; Reguera, E.; Stein, A., Tunable Colors in Opals and Inverse Opal Photonic Crystals. Advanced Functional Materials 2010, 20 (16), 2565-2578.Zhang, Y.; Qiu, J.; Hu, R.; Li, P.; Gao, L.; Heng, L.; Tang, B. Z.; Jiang, L., A visual and organic vapor sensitive photonic crystal sensor consisting of polymer-infiltrated SiO2 inverse opal. Physical Chemistry Chemical Physics 2015, 17 (15), 9651-9658.Li, H.; Chang, L.; Wang, J.; Yang, L.; Song, Y., A colorful oil-sensitive carbon inverse opal. Journal of Materials Chemistry 2008, 18 (42), 5098-5103.Chen, J. I. L.; von Freymann, G.; Choi, S. Y.; Kitaev, V.; Ozin, G. A., Amplified Photochemistry with Slow Photons. Advanced Materials 2006, 18 (14), 1915-1919.Collins, G.; Lonergan, A.; McNulty, D.; Glynn, C.; Buckley, D.; Hu, C.; O'Dwyer, C., Semiconducting Metal Oxide Photonic Crystal Plasmonic Photocatalysts. Advanced Materials Interfaces 2020, 7 (8), 1901805.Liu, L.; Karuturi, S. K.; Su, L. T.; Tok, A. I. Y., TiO2 inverse-opal electrode fabricated by atomic layer deposition for dye-sensitized solar cell applications. Energy & Environmental Science 2011, 4 (1), 209-215. Figure 1 SEM images and optical transmission spectra for (a) TiO2 and (b) SnO2 inverse opals. In each case the wavelength position of the photonic stopband is red-shifted significantly when a solvent infiltrates the porous photonic crystal network. SEM images and optical transmission spectra for (c) artificial polystyrene opals coated with a gold film and (d) TiO2 inverse opals coated with a copper film. Metal film incorporation into the photonic crystal network acts to consistent blue-shift the observed photonic stopband. Figure 1

A locust bean and pectin polymer blend integrated with thio-bridged pyridinyl additive as a novel cobalt and copper gel electrolyte system for dye-sensitized solar cells

An intensive correlation has been attempted on 2-(pyridin-2-yl)-1-(4-(trifluoromethyl)phenyl)-1H-benzo[d]imidazole ligand-coordinated cobalt and copper metal complex electrolytes (Co2+/3+[ptpbi]3 and Cu1+/2+[ptpbi]2) with blend biopolymer electrolyte based on Locust Bean Gum and Pectin (LP) as a host matrix to enhance the performance of organic DPTCY sensitizer (2D-π-D′-A-π-A). Comparatively, the ligand coupled bulky CF3 acceptor on the para position of benzyl moiety-substituted 2-(pyridin-2-yl)-benzimidazole (on the N–H position) [ptpbi]-coordinated copper metal complex shows a higher redox potential (0.62 V vs NHE) compare to Co2+/3+ redox system. The photovoltaic performance of thio-bridged pyridinyl based organic compounds (MPP and DSP) with/without highly electron-donating substituents (methyl group) as an additive in QSSE host for dye-sensitized solar cell applications has been employed. A thorough investigation has been made for blending polysaccharide polymer-based electrolytes E1 to E4 through DSC, FTIR, UV–Vis spectroscopic techniques. The analysis of assembled device as [TiO2/DPTCY Dye/Mn+/m + redox/additive/LP blend biopolymer/Pt] has achieved a maximum PCE of 5.97% under 1 sun (100 mW cm−2) condition with 1.5AM. These results signify a record for copper complex with methyl-substituted thio-bridged pyridinyl (MPP) with higher efficiency. These devices had shown a higher chemical capacitance (6.06 × 10−6 F), recombination resistance (25.5 Ω), charge transfer resistance (5.67 Ω), ionic conductivity (1.568 (S cm−1) × 10−3), electron lifetime (48.97 ms), diffusion coefficient (2.63 × 10−7 cm−2 s), dielectric constant (2.76 × 102) and dielectric loss (4.41 × 103) compared with other substitution-based additives. These additives have trapped the diffusion of Cu2+ and Co3+ ion species has resulted in the constraint resistance and enhancement of the catalytic effect of the counter electrode. The higher charge relaxation time and a negative shift in the Quasi-Fermi level of TiO2 arise by correlating photocurrent and photovoltage in suppression of recombination reaction.

Transformation of ZnS microspheres to ZnO, their computational (DFT) validation and dye-sensitized solar cells application

ZnO spheres were synthesized by solid state oxidation of ZnS microspheres at different oxidation temperatures of 600 and 700 °C in an ambient atmosphere. The high temperature transformation of ZnS microspheres into hexagonal structured and highly crystalline ZnO microspheres comprising interconnected nanoparticles facilitating efficiently electron transport as well as charge collection through an intended path in the solar cell. The comparative physico-chemical and photovoltaic studies were done for synthesized ZnO microspheres. The structural study by x-ray diffraction of ZnO confirmed the hexagonal ZnO; the UV–Visible spectroscopy study showed λmax varying from 410 to 413 nm and 397 to 407 nm for ZnO microspheres synthesized by heating at 600 and at 700 °C, respectively. Additionally, crystalline and electronic structures were validated by density functional theory studies. The computational studies also revealed growth of hexagonal ZnO, where the bandgap varied with the oxidation temperature. The photovoltaic properties of ZnO microspheres synthesized at 600 °C exhibited better performance than the ones synthesized at 700 °C due to high surface roughness leading to enhanced dye loading and favorable charge collection. Dye-sensitized solar cells fabricated from ZnO microspheres synthesized at 600 and 700 °C exhibited the maximum power conversion efficiency of 3.38% and 3.06% correspondingly.

Influence of thickness and morphology of MoS2 on the performance of counter electrodes in dye-sensitized solar cells.

Non-platinum electrodes for photoelectric devices are challenging and attractive to the scientific community. A thin film of molybdenum disulfide (MoS2) was prepared on substrates coated with fluorine-doped tin oxide (FTO) to substitute the platinum counter electrode (CE) for dye-sensitized solar cells (DSSCs). Herein, we synthesized layered and honeycomb-like MoS2 thin films via the cyclic voltammetry (CV) route. Thickness and morphology of the MoS2 thin films were controlled via the concentration of precursor solution. The obtained results showed that MoS2 thin films formed at a low precursor concentration had a layered morphology while a honeycomb-like MoS2 thin film was formed at a high precursor concentration. Both types of MoS2 thin film were composed of 1T and 2H structures and exhibited excellent electrocatalytic activity for the I3–/I− redox couple. DSSCs assembled using these MoS2 CEs showed a maximal power conversion efficiency of 7.33%. The short-circuit value reached 16.3 mA·cm−2, which was higher than that of a conventional Pt/FTO CE (15.3 mA·cm−2). This work reports for the first time the possibility to obtain a honeycomb-like MoS2 thin film morphology by the CV method and investigates the effect of film structure on the electrocatalytic activity and photovoltaic performance of CEs for DSSC application.

α-Fe2O3/Reduced Graphene Oxide Composites as Cost-Effective Counter Electrode for Dye-Sensitized Solar Cells

The counter electrode (CE) is an important and vital part of dye-sensitized solar cells (DSSCs). Pt CEs show high-performance in DSSCs using iodide-based electrolytes. However, the high cost of Pt CEs restricts their large-scale application in DSSCs and the development of Pt-free CE is expected. Here, α-Fe2O3/reduced graphene oxide (α-Fe2O3/RGO) composites are prepared as the Pt-free CE materials for DSSCs. A simple hydrothermal technique was used to disseminate the α-Fe2O3 solid nanoparticles uniformly throughout the RGO surface. The presence of the α-Fe2O3 nanoparticles increases the specific surface area of RGO and allows the composites to be porous, which improves the diffusion of liquid electrolyte into the CE material. Then, the electrocatalytic properties of CEs with α-Fe2O3/RGO, α-Fe2O3, RGO, and Pt materials are compared. The α-Fe2O3/RGO CE has a similar electrocatalytic performance to Pt CE, which is superior to those of the pure α-Fe2O3 and RGO CEs. After being fabricated as DSSCs, the current–voltage measurements reveal that the DSSC based on α-Fe2O3/RGO CE has a power conversion efficiency (PCE) of 6.12%, which is 88% that of Pt CE and much higher than that of pure α-Fe2O3 and pure RGO CEs. All the results show that this work describes a promising material for cost-effective, Pt-free CEs for DSSCs.

Exploring Structure-Property Relationships in a Family of Ferrocene-Containing, Triphenylamine-Based Hybrid Organic Dyes

In this work, a new family of triphenylamine-based dyes equipped with ferrocene (Fc)-containing donors have been synthesized, characterized, and studied within dye-sensitized solar cells (DSSC). With the objective of designing a redox-robust iron-containing dye that effectively sensitizes titania, a family of five structurally related dyes containing ferrocene were prepared. The physicochemical properties of all dyestuffs were studied using UV-Vis and electrochemical measurements. Different cross-coupling strategies resulted in the ability to modestly tune the Fc/Fc+ redox potentials of the dye. Despite the Fc-containing dyes having optoelectronic properties consistent with the non-ferrocene parent dye, the performance of the dyes in devices was dismal and decreased with the number of appended ferrocenes. While this finding was consistent with previous attempts to explore Fc-TPA DSSC dyes, our spectroelectrochemical data supports the hypothesis that the ferrocene component of the dye is oxidized by the electrolyte, ultimately decreasing the dye’s ability to be a suitable sensitizer. While these dyes are not suitable for DSSC applications, they might find applications in other photo-induced integrated devices where charge recombination is minimal.

Synthesis and characterization of a series of cobalt complexes: Investigation of their efficacy as sensitizers in dye-sensitized solar cell applications

A series of cobalt(II) complexes possessing diverse structural and electronic properties were prepared by using varieties of ligand systems. All the complexes were thoroughly characterized by spectral and analytical and techniques including X-ray crystallography and the molecular structures were optimized by DFT studies (M06 & B3LYP methods). The theoretical HOMO-LUMO energy gaps were compared with the optical band gap energies calculated using Tauc plot. Utility of the prepared cobalt (II/III) complexes as sensitizers in the dye-sensitized solar cell was investigated. I–V parameters of the fabricated solar cells were noted and compared with the cell made using standard N719 dye. Among the twenty-one complexes investigated, complex C4, comprising of bis(pyrazolyl)methane ligands exhibited highest power conversion efficiency.

Building triple shelled ZnO hollow microspheres decorated TiO2 nanotree to boost light harvesting and reduced charges recombination in dye sensitized solar cell

It is well known that the microstructure of photoanode materials has direct influence on light harvesting and charges recombination in dye sensitized solar cells (DSSC). However, design of photoanode materials for efficient light harvesting and electron transport is still in challenge. Therefore, we developed a hierarchical microstructure of multi shelled ZnO hollow microspheres (MS ZnO HMS) decorated TiO2 nanotree (NT) for DSSCs application with aim to take advantages of enhanced light scattering and enlarged specific area offered by MS ZnO HMS and reduced charges recombination provide by TiO2 NT. The morphology, microstructure and crystalline of ZnO HMS and TiO2 NT have been characterized by SEM, TEM and XRD, confirming the successful building of MS ZnO HMS decorated TiO2 NT. I–V tests show that significant enhancement of short-circuit current density (Jsc) can be achieved by controlling shell numbers of MS ZnO HMS and combining MS ZnO HMS with TiO2 NT. As a result, the triple shelled ZnO HMS (TS ZnO HMS) decorated TiO2 NT (TS ZnO HMS/TiO2 NT) improve the power conversion efficiency (PCE) to 7.40%, which is 138% and 40% higher than DSSCs based on TiO2 NT (3.11%) and TS ZnO HMS (5.27%). IPCE, OCVD and EIS measurements indicate that the combination of TS ZnO HMS with TiO2 NT contribute to the improvement of light harvesting efficiency and prolonging of electron lifetime.

Design and synthesis of novel bichalcophene derivatives with double anchoring groups for dye-sensitized solar cell applications: sensitization and co-sensitization with N-719

Design and synthesis of novel bichalcophene derivatives with double anchoring groups for dye-sensitized solar cell applications: sensitization and co-sensitization with N-719

A Review And Comparative Analysis Of Different Types Of Dyes For Applications In Dye-Sensitized Solar Cells

A Review And Comparative Analysis Of Different Types Of Dyes For Applications In Dye-Sensitized Solar Cells

Star-type melamine based conjugated carboxy functionalized porphyrin trimer for DSSCs: An efficient approach to clean, aggregation free and true energy generation

A novel, π-conjugated melamine-based trimeric porphyrin dye with serving nine carboxylate linker groups has been prepared to use as a panchromatic dye for application in dye-sensitized solar cells (DSSCs). The star-shaped trimer was characterized by using Proton Nuclear Magnetic Resonance (NMR) Spectroscopy, Carbon Nuclear Magnetic Resonance Spectroscopy (CMR), Fourier Transformed Infrared Spectroscopy (FT-IR), UV-VIS Absorption Spectroscopy, Thermo-gravimetric analysis (TGA), Cyclic Voltammetry (CV) and Electrochemical Impedance Studies (EIS). CV studies revealed frontiers energy levels at −5.654 (HOMO) and −3.879 eV (LUMO) versus vacuum. The optical band gap evolved via absorption spectra measurements was found to be 1.49 eV. A planar perfect conjugation among three porphyrins sets up multiple push-pull communication and lowers the bandgap, while nine carboxylate linkers cover-up TiO2 surface effectively leading to better electronic dynamics. The DSSC set up using iodide-based redox couples forms a simple, stable, additive-free, truly energy generating device with 7.1% conversion efficiency, the highest among trimeric porphyrin category.