Application In Dye-sensitized Solar Cells Research Articles

Computational investigations on efficient metal-free organic D-π-A dyes with different spacers for powerful DSSCs applications

ABSTRACT Based on 3-(4-((4-carbazol-9-yl-phenyl)ethynyl)phenyl)-2-cyanoacrylic acid (CB1) dye, the six newly planned organic spacer (CBS1-CBS6) dyes were investigated for dye-sensitised solar cell (DSSC) application. The designed dyes have an electron-donor (D) in carbazole through a different π-spacer and an electron-acceptor (A) in 2-cyanoacrylic acid. The density functional theory (DFT) and the time-dependent DFT (TD-DFT) evaluated the DSSCs of the molecules in the strategic platform. The results display that the TD-DFT method, using different functionals with exchange (XC) and long-range correlated (LC), was discussed. The electronic and optical properties of the CBS1-CBS6 dyes were discussed. The highest occupied molecular orbitals (HOMOs) and lowest unoccupied MOs (LUMOs) of the CBS1-CBS6 molecules can confirm the probable response to the regeneration and electron injection process. Also, the calculated results, such as injection driving force , light-harvesting efficiencies (LHE), regeneration and open-circuit photovoltage of the CBS1-CBS6 sensitisers, were presented. A good contract of theoretical calculations with the literature data reveals a better understanding of the spacer's PV performance. To conclude, benzo[c][1,2,5]oxadiazole (CBS2) and [1,2,5]oxadiazolo[3,4-c]pyridine (CBS5) spacers were the best candidates for DSSCs, because of their smaller energy gap and red-shifted absorption wavelengths.

Different metal upper porphyrin based self-assembly sensitizers for application in efficient dye-sensitized solar cells

Four different metal atom dyes MP (M: Zn, Cd, Ag, Cu) as upper porphyrin molecular have been designed and synthesized. On the other side of ZnPA contains four carboxylic acids as the horizontal anchor porphyrin for binding to TiO2. We constructed MP-ZnPA assembled approach, and applied in dye-sensitized solar cells. Photoelectrochemical studies reveal the self-assembled structure dye photocurrent (Jsc) are higher than anchor porphyrin. The enhancement of Jsc can be ascribed to the improved light-harvesting ability induced by the axially coordinated MP. However, upper different metal atom porphyrins cannot play a positive role in improving the photovoltages (Voc) because of MP-ZnPA devices possess the dye aggregation. The effects of the MP-ZnPA assembled on the optical, theory calculations and photovoltaic properties were investigated. AgP-ZnPA and ZnP-ZnPA have the higher molar extinction coefficient and sufficient charge injection into the TiO2 conduction band. Therefore, AgP-ZnPA and ZnP-ZnPA have superior photovoltaic behavior. We constructed a three-layer self-assembled (ZnP1-AgP-ZnPA) solar cell, which the photovoltaic efficiency of the three-layer self-assembled solar cell is significantly reduced. Consequently, double-layer self-assembly, which is one of the effective strategies for improving the performance of self-assembly supramolecular solar cells.

DFT and TD-DFT studies for optoelectronic properties of coumarin based donor-π-acceptor (D-π-A) dyes: applications in dye-sensitized solar cells (DSSCS)

A series of six coumarin based dye derivatives were investigated and their geometry and optoelectronic properties elucidated for suitability in dye-sensitized solar cells (DSSCs) using TD-DFT/B3LYP with 6-31G basis set. D-π-A schemes were developed by attaching various donors and acceptors to coumarin dye (CM) to calculate changes in their photovoltaic properties. D2-CM-A2 and D4-CM-A4 showed less dihedral angle because of the low steric effect between donor and connector. The D1-CM-A1 and D2-CM-A2 results of intramolecular charge transfer were higher because of low bond length and a strong group of electron donors. The results revealed that LUMO energies of D1-CM-A1, D2-CM-A2, D3-CM-A3 and D4-CM-A4 were higher than the conduction band edge of TiO2 electrode (−4.0 eV) suggesting that these dyes will inject the electrons into the conduction band of the semiconductor. In addition, the light harvest efficiency (LHE), open-circuit voltage (VOC) and band energy gap (Eg) values are calculated in the gas phase, as well as in the solvent phase. This study shows that D1-CM-D1 and D2-CM-A2 derivatives have better properties for application in the DSSCs.

Novel Down-converting single-phased white light Pr3+ doped BaWO4 Nanophosphors material for DSSC applications

White Nanophosphors based on praseodymium doped barium tungstate matrix (y mol Pr3+: BaWO4 (PBWO) (y = 0.01, 0.03, 0.05, 0.07 mol) were synthesized by ultrasound assisted hydrothermal method in the presence of citric acid and characterized as novel down-conversion materials for dye-sensitized solar cells (DSSCs) applications. The different prepared PBWO Nanophosphors show high crystalline tetragonal phase with nano-cubic morphology. The PBWO photoluminescence spectra give strong emission peaks at 486, 529, 615, 623 and 643 nm are corresponding to the 3P0→3H4, 3P1→3H5, 1D2→3H4, 3P0→3H6 and 3P0→3F2 transitions of Pr3+, respectively. These photoluminescence spectra are assigned to blue, green and red-light regions which cover the whole visible light region. It means that these Nanophosphor materials are promising materials for down-conversion applications. By varying the Pr3+ ion conc., it was found that the optimum conc. of Pr3+ ion was 0.05 mol which gives the highest photoluminescence intensity. The prepared Nanophosphors were applied in DSSCs as a top down-converting layer on the photoactive TiO2 electrode. A high conversion efficiency (η) of 8.08% was achieved by the application of top (PBWO: 0.05 mol Pr3+) down-converting material compared with a 4.17% efficiency of the non-modified DSSC. This enhancement is probably due to the improved UV radiation harvesting via a down-conversion luminescence process.

Analysis and Prediction of Hydrothermally Synthesized ZnO-Based Dye-Sensitized Solar Cell Properties Using Statistical and Machine-Learning Techniques.

Dye-sensitized solar cells (DSSCs) are one of the most versatile and low-cost solar cells. However, DSSCs are prone to low power conversion efficiency (PCE) compared to their counterparts, owing to their different synthesis parameters and process conditions. Therefore, designing efficient DSSCs and identifying the parameters that control the PCE of DSSCs are a critical tasks. We have collected data from hydrothermally synthesized DSSCs in the present work, published from 2005 to 2020. In line with publishing trends in the said period, we evaluate ZnO as a popular photoactive material for DSSC applications. We further analyzed the performance of hydrothermally synthesized ZnO DSSCs using different statistical techniques and provided some significant insights. We further applied the machine-learning technique with a decision tree algorithm to understand and discover the possible set of rules and heuristics that govern the morphology of the hydrothermally grown ZnO. In addition, we also employed supervised and unsupervised machine-learning models using conventional decision trees and classification and regression trees, respectively, to identify the dependence of the PCE of ZnO DSSCs on the different synthesis parameters. The reported work also evidences the PCE predictions of the ZnO DSSCs by using random forest and artificial neural network algorithms. The results substantiate that the random forest and artificial neural network algorithms successfully predict the PCE of the ZnO DSSCs with reasonable accuracy. Thus, we present a novel approach of applying statistical analysis and machine-learning algorithms to understand, discover, and predict the performance of DSSCs. We recommend extending the said know-how to other solar cells to identify rules and heuristics and experimentally realize highly efficient solar cells in shrinking manufacturing windows with a cost-effective approach.

Effect of High Dielectric SrF2 in TiO2 photoanode for Dye-Sensitized Solar Cell Applications

Dye-sensitized solar cells (DSSC) have been extensively investigated as promising candidate for solar energy conversion owing to their low cost, eco-friendly and high device efficiency. Among the other, photoanode is one of the key components in DSSC which defines its performance. Charge recombination and low light harvesting are the two major drawbacks of conventional TiO2 photoanode which limits the device efficiency. With this aim, the present work focused on the preparation of high dielectric SrF2 nanoparticles (ε’=6.844 x 106 at 1 Hz) and its study on incorporation with TiO2 photoanode with various weight percentages for device assembly. It can reduce the recombination by strong electrostatic shielding and increase the charge collection efficiency through interfacial polarization at dielectric-semiconductor interface shown in Fig.1. Improved power conversion efficiency (PCE) of 7.581% is obtained in 10 wt% SrF2:90 wt% TiO2 based photoanode which is 8.3% higher than the device efficiency of pure TiO2 based DSSC (6.997%). The interfacial charge transport kinetics of fabricated DSSCs are also explored using electrochemical impedance spectral (EIS) analysis. Low recombination resistance Rrec (49.9 Ω) in 10 wt% SrF2:90 wt% TiO2 based DSSC reveals the reduced recombination dynamics compared to other devices due to the optimized concentration of SrF2 incorporation in TiO2 photoanode for balancing charge injection and recombination. Keywords: DSSC; SrF2; Interfacial polarization; Dielectric constant and EIS Acknowledgement: This work was supported by Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, Korea. (Grant number: 2019H1D3A1A01071183). It was also supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation, funded by the Ministry of Science, ICT & Future Planning (No: NRF-2016M1A2A2940912). Fi gure.1. Dielectric plot as a function of angular frequency (Inset shows interfacial polarization at dielectric-semiconductor interface). Figure 1

The Effect of Plasticizers on the Polypyrrole-Poly(vinyl alcohol)-Based Conducting Polymer Electrolyte and Its Application in Semi-Transparent Dye-Sensitized Solar Cells.

In this work, the quasi-solid-state polymer electrolyte containing poly(vinyl alcohol)-polypyrrole as a polymer host, potassium iodide (KI), iodine (I2), and different plasticizers (EC, PC, GBL, and DBP) was successfully prepared via the solution casting technique. Fourier transform infrared spectroscopy (FTIR) was used to analyze the interaction between the polymer and the plasticizer. X-ray diffraction confirmed the reduction of crystallinity in the polymer electrolyte by plasticizer doping. The ethylene carbonate-based polymer electrolyte showed maximum electrical conductivity of 0.496 S cm−1. The lowest activation energy of 0.863 kJ mol−1 was obtained for the EC-doped polymer electrolyte. The lowest charge transfer resistance Rct1 was due to a faster charge transfer at the counter electrode/electrolyte interface. The polymer electrolyte containing the EC plasticizer exhibited an average roughness of 23.918 nm. A photo-conversion efficiency of 4.19% was recorded in the DSSC with the EC-doped polymer electrolyte under the illumination of 100 mWcm−2.

Photoelectrochemical properties of WO3-modified anatase TiO2 photoanodes and application for dye-sensitized solar cells

TiO2 electrodes were modified with different WO3 loadings and photoelectrochemical characterization revealed an increase in photocurrent density and decrease in interface charge transfer resistance with increasing amount of WO3. A decrease in green PL was observed with WO3 addition indicating more mobility of charges and therefore less probability of recombination. A series of TiO2 photoanodes modified by WO3 were designed with different geometrical configurations for dye-sensitized solar cell (DSSC) applications, WO3 was introduced successively in the screen-printed paste, as an undercoat and in the TiCl4 pretreatment bath. The results indicated a decrease in photovoltaic performance of all devices modified by WO3 compared to TiO2 reference cell. The highest conversion efficiency of the modified cells was observed for the configuration of WO3 introduced into the TiCl4 pretreatment bath. In this case, the optimized contact between the coupled semiconductors improved the charge transfer, also the direct contact of WO3 with the FTO substrate decreased the loss of electrons by confinement and recombination.

Dual heteroatom-doped reduced graphene oxide and its application in dye-sensitized solar cells

The quick reduction and regeneration of the electrolyte (triiodide/iodide redox couple, I3−/I−) is one of the main issues in dye-sensitized solar cells (DSSCs). The well-known platinum counter electrodes (CEs) that facilitate electrolyte reduction and regeneration are very expensive; hence, low-cost and efficient CEs are in demand to substitute the platinum CEs. Herein, we report the hydrothermal synthesis of single (boron or nitrogen) and dual (boron/nitrogen mixture) heteroatom-doped reduced graphene oxide (rGO) and their comparison as CEs in DSSCs. The photovoltaic, electrochemical and conductivity properties were investigated. Dual heteroatom-doped rGO demonstrated a relatively large surface area and enhanced electrical conductivity (161.51 m2 g−1 and 22.07 S cm−1, respectively) when compared to graphene oxide (GO), rGO and single heteroatom-doped rGO. The amount of boron- and nitrogen-doping, including their configuration, played a crucial role in the catalytic activity. The presence of pyridinic-N and pyrrolic-N in single and dual heteroatom-doped rGO promoted a triiodide reduction reaction, which shifted the redox potential, relative to GO and rGO. The BN-rGO-3 CE yielded a relatively higher PCE of 2.97%, further enhanced to 4.13% when the BN-rGO-3 CE was used in conjunction with polyaniline as a binder. Therefore, this showed that dual heteroatom-doped rGO CEs enhanced the PCE of the DSSCs due to the synergetic effect, doping configuration and higher doping levels. Thus, the present work provides a facile and productive strategy for configuring the dual heteroatom-doped graphene CE materials with high electrocatalytic activity for energy conversion devices.

Architectural design of new conjugated systems carrying donor-π-acceptor groups (carbazole-CF3): Characterizations, optical, photophysical properties and DSSC's applications

In this study, two new organic dyes containing substituted N-octyl carbazole as electron donor and -CF3 units as electron acceptor group were designed and synthesized for ZnO-based dye sensitized solar cells (DSSCs). The synthesized carbazole derivatized compounds 3,6-bis(3,5-bis(trifluoromethyl)phenyl)-9-octyl-9H-carbazole (IVa) and 3,6-bis(4-(trifluoromethyl)phenyl)-9-octyl-9H-carbazole (IVb) were characterized by FT-IR, 1H NMR, 13C NMR, HMBC and CHN analyses. The spectroscopic (UV–Vis and FL) and thermal properties (TGA-DTA) of these compounds were also investigated. The produced (IVa and IVb) ZnO films were used as photoanodes in all DSSCs. Microwave-assisted hydrothermal method was used to synthesize ZnO nanopowders with different morphologies which are used as photoanodes in DSSCs. The structural and morphological properties of ZnO nanopowders were investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). ZnO-DSSCs were produced through coating ZnO nanopowders on transparent conductive fluorine-doped tin oxide (FTO) coated glass substrate using the Doctor Blade method. Current-voltage measurements of all produced DSSCs were carried out under a solar simulator with AM 1.5 G filter having an irradiance of 100 mW/cm2. Solar cell performances of all DSSCs such as; open-circuit voltage (Voc), short circuit current (Jsc), fill factor (FF) and power conversion efficiency (PCE) were analyzed.

Efficient Iron Phosphide Catalyst as a Counter Electrode in Dye-Sensitized Solar Cells

Developing an efficient material as a counter electrode (CE) with excellent catalytic activity, intrinsic stability, and low cost is essential for the commercial application of dye-sensitized solar cells (DSSCs). Transition metal phosphides have been demonstrated as outstanding multifunctional catalysts in a broad range of energy conversion technologies. Here, we exploited different phases of iron phosphide as CEs in DSSCs with an I–/I3–-based electrolyte. Solvothermal synthesis using a triphenylphosphine precursor as a phosphorus source allows to grow a Fe2P phase at 300 °C and a FeP phase at 350 °C. The obtained iron phosphide catalysts were coated on fluorine-doped tin oxide substrates and heat-treated at 450 °C under an inert gas atmosphere. The solar-to-current conversion efficiency of the solar cells assembled with the Fe2P material reached 3.96 ± 0.06%, which is comparable to the device assembled with a platinum (Pt) CE. DFT calculations support the experimental observations and explain the fundamental origin behind the improved performance of Fe2P compared to FeP. These results indicate that the Fe2P catalyst exhibits excellent performance along with desired stability to be deployed as an efficient Pt-free alternative in DSSCs.

Enhanced electrocatalytic activity in dye-sensitized solar cells via interface coupling of the CoFe2O4/Co3Fe7 heterostructure

The DSSC assembled with CoFe/CFO CE exhibits a higher power conversion efficiency (8.54%), which surpasses that of conventional Pt (7.70%). Such excellent performance can be ascribed to the unique interfacial structural optimization and intimate interface coupling synergies. The original core-shell layer enriches the active sites, and further structural integration improves the interface, increasing the conductivity while synergistically accelerating the catalytic activity. • Synthesis of CoFe 2 O 4 /Co 3 Fe 7 hybrids by hydrothermal and impregnation methods. • Structural integration and multi-component synergy maximize catalytic activity. • DSSC based on CoFe 2 O 4 /Co 3 Fe 7 CE exhibited higher PCE (8.54%) than Pt (7.70%). The exploitation of high-efficient yet non-precious counter electrode (CE) materials is of great significance for practical applications of dye-sensitized solar cells (DSSCs). Herein, Co 3 Fe 7 alloy anchored on the porous core-shell CoFe 2 O 4 composites (CoFe 2 O 4 /Co 3 Fe 7 ) were successfully manufactured as a counter electrode for DSSC. The detailed electrochemical measurements verified that the introduction of Co 3 Fe 7 alloys modifies the original core-shell structure, contributing to enhance electrical conductivity and promote interfacial electron transfer. While the porous structure increases the potential for exposing active sites and accelerates the diffusion of iodide ions. Moreover, the formation of hetero-junction facilitates the generation of active facet sharing and multi-component synergy, thus prominently boosting the reduction of triiodide and accelerating reaction kinetics. As a consequence, DSSCs structured with CoFe 2 O 4 /Co 3 Fe 7 -modified CEs achieve a satisfactory power conversion efficiency (PCE) of 8.54%, which surpasses that of conventional platinum (7.70%). Meanwhile, the stability of CoFe 2 O 4 /Co 3 Fe 7 CE is also enhanced than noble metals platinum. This work highlights that the heterogeneous CoFe 2 O 4 /Co 3 Fe 7 with a rich interface can effectively stimulate the catalytic activity of reducing triiodide to enhance the performance of the solar cell. This strategy also paves the way for enhancing material activity in the field of energy storage and conversion.

Hydrothermal growth optimization of vertically aligned ZnO nanowire arrays and their dye-sensitized solar cell performance under air/oxygen environments

In this work, the hydrothermal growth parameters of vertically aligned ZnO nanowire arrays on FTO substrates were optimized for best surface coverage and minimal stacking and entanglement between nanowires for dye-sensitized solar cell (DSSC) application. The concentration of seed layer solution was found to be essential in reducing the stacking effect of adjacent nanowires. The growth temperature study has revealed a remarkable existence of a temperature window in the range 90 °C–110 °C, beyond which the nanowire lengths start to decline. We attributed the nanowire length regression above 110 °C to the enhanced homogeneous nucleations in the growth solution. Nanowire entanglement started to be observable at ∼100 °C for a growth duration of 2 h. DSSCs were fabricated using the grown ZnO nanowire arrays that are post-annealed under air and pure oxygen gas environments. Oxygen post-annealing resulted in a remarkable decrease in the open circuit voltage (VOC), which we attributed to the large impact of band bending.

Facile synthesis of undoped and Sn doped CdS nanoparticles for dye-sensitized solar cell applications

Undoped and tin (Sn) doped cadmium sulfide (CdS) semiconductor alloy nanoparticles have been prepared by simple solvothermal microwave irradiation (SMI) technique. Powder X-ray diffraction (PXRD) analysis indicates the formation of hexagonal structured high-quality nanoparticles with crystallite size around 3 nm. The particle size of the samples obtained from transmission electron microscopy (TEM) analysis is in accordance with the crystallite size of prepared nanoparticles. The surface morphology examined using a field emission scanning electron microscope shows the uniform distribution of spherical nanoparticles. The energy dispersive X-ray (EDX) analysis confirms the purity of the prepared nanoparticles with a good stoichiometric ratio of Cd, S, and Sn. The optical characteristic of the samples by UV–Visible (UV–Vis.) analysis implies that the optical band gap tends to decrease for the increase in Sn concentration in CdS lattices. Dye-sensitized solar cell with 4 mol % Sn doped CdS nanoparticles shows ~39% higher efficiency than that of undoped CdS.

Effects of PbS-NPs doping on the photovoltaic performance of natural dye-sensitized TiO2 photoelectrodes

In this work, we report the synthesis of TiO2 photoelectrodes sensitized with different natural organic dyes extracted (using methanol) from spinach, raspberry and passion fruit for their application in Dye-Sensitized Solar Cells (DSSC). The effects of Lead Sulfide (PbS) NanoParticles (NPs) doping on the sensitized TiO2 photoelectrodes photovoltaic performance were mainly studied. Good absorption in the visible range (400–700 [nm]) was observed for natural dyes extracted from spinach and raspberry, observing characteristic peaks associated with chlorophylls, β-carotenes and phycoerythrin pigments. On the other hand, natural dye synthesized from passion fruit showed a poor absorption in this range concerning the previous mentioned sources. Cells using spinach and raspberry based dyes generally showed good Fill Factors (FF) higher than 55%, observing depreciable or negative influence of the PbS doping. Open-Circuit voltages (Voc), Short-Circuit current densities (Jsc) and Power Conversion Efficiencies (PCE) in the range of 0.35–0.55 [V], 0.01–0.12 [mA/cm2] and 0.002–0.03 [%] were respectively estimated.

Effect of the potassium iodide in tetrapropyl ammonium iodide-polyvinyl alcohol based gel polymer electrolyte for dye-sensitized solar cells

Low ionic conductivity in gel polymer electrolytes with large cations is undoubtedly a critical issue. This research’s main objective was to explore potassium iodide influences on the conductivity in gel polymer electrolytes. PVA-based gel polymer electrolytes (GPEs), including tetrapropyl ammonium iodide and potassium iodide have been prepared. The GPEs have been characterized by X-ray diffraction (XRD) and electrical impedance spectroscopy (EIS). The GPEs prepared haves been recognized as an amorphous region through the X-ray diffraction analysis. The GPE sample’s conductivity (100 wt% of tetrapropyl ammonium iodide) of 6.24 × 10−3 S cm−1 was the lowest. The existence of potassium iodide in the GPE system improves the conductivity. The conductivity of 9.72 × 10−3 S cm−1 of GPE containing 30 wt% of tetrapropyl ammonium iodide and 70 wt% of potassium iodide was the highest derived from the EIS analysis. All prepared GPEs have the potential to be used for dye-sensitized solar cell applications. The dye-sensitized solar cell efficiency has been improved by ~30% if potassium iodide exists in the GPE system.

Introduction of Pt-free counter electrode based on f-MWCNTs@NiMoSe2 nanocomposite for efficient dye-sensitized solar cells

Herein, we have demonstrated the synthesis of carboxylic functionalized multi-walled carbon nanotubes (f-MWCNTs) encapsulated Ni-doped Molybdenum diselenide 2D nanosheets (f-MWCNTs@NiMoSe2) by cost-effective hydrothermal technique and served as a potential catalytic material in the dye-sensitized solar cells (DSSCs). The surface morphology and chemical information of the catalyst have been studied through the field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. Taking the electrochemical characterizations including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Tafel, and power conversion efficiency (PCE) measurements exhibited that f-MWCNTs@NiMoSe2 delivered a better electrocatalytic behavior and outstanding chemical stability. The DSSCs fabricated with f-MWCNTs@NiMoSe2 revealed the most impressive catalytic activity with remarkable PCE of 7.39% versus Pt-based standard electrode (PCE: 6.10%). These results indicate that the substitution of Ni and presence of MWCNTs significantly enrich the active sites and electrical conductivity of MoSe2. Finally, the f-MWCNTs@NiMoSe2 gives a new opportunity for promising commercial application in DSSCs.

Graphene Quantum Dots Supported Mo3S4 as a Promising Candidate for Pt-Free Counter Electrode in Dye-Sensitized Solar Cell and Supercapacitor Applications

We have synthesized with and without graphene quantum dots (GQDs) supported Molybdenum sulfide (Mo3S4/GQDs) by the hydrothermal route and examined the effect on electrochemical and dye sensitized solar cells (DSSCs) performance. The crystalline structure and composition are elucidated by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The synthesized samples show a spherical nature which is confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). JV spectra reveal GQDs modified Mo3S4 counter electrodes deliver the highest short circuit current (J SC ) of 13.84 mA cm−2, open-circuit voltage (V OC ) of 0.72 V, and power conversion efficiency (PCE) of 5.67%, which is 13% higher compared to pristine counter electrodes. Low peak to peak separation (Epp) and higher peak current density (Jpc) and exchange current density (Jo) are responsible for this improvement. Besides, the samples have been employed as a working electrode and studied supercapacitor performance. Among them, Mo3S4/GQDs exhibited the highest specific capacitance of 234 F g−1 at 2 A g−1. The results mentioned above reveal GQDs supported Mo3S4 is not only a viable substitute for Pt-free counter electrodes but also provide a better outlook for energy storage devices.

Organic Functionalized Carbon Nanostructures for Solar Energy Conversion.

This review presents an overview of the use of organic functionalized carbon nanostructures (CNSs) in solar energy conversion schemes. Our attention was focused in particular on the contribution of organic chemistry to the development of new hybrid materials that find application in dye-sensitized solar cells (DSSCs), organic photovoltaics (OPVs), and perovskite solar cells (PSCs), as well as in photocatalytic fuel production, focusing in particular on the most recent literature. The request for new materials able to accompany the green energy transition that are abundant, low-cost, low-toxicity, and made from renewable sources has further increased the interest in CNSs that meet all these requirements. The inclusion of an organic molecule, thanks to both covalent and non-covalent interactions, in a CNS leads to the development of a completely new hybrid material able of combining and improving the properties of both starting materials. In addition to the numerical data, which unequivocally state the positive effect of the new hybrid material, we hope that these examples can inspire further research in the field of photoactive materials from an organic point of view.

Designing LiBOB-based electrolyte for dye-sensitised solar cell

ABSTRACT Liquid electrolyte based on lithium bis(oxalato)borate (LiBOB) polymer was prepared for the application in dye-sensitised solar cells (DSSCs). The electrolyte was optimised with varying content of 4-tert-butylpyridine (4TBP), guanidinium thiocyanate (GuCN), iodine and 1-propyl-3-methylimidazolium iodide (PMII) ionic liquid. Better cell performance was observed in solar cell devices with LiBOB-based electrolyte consisting of 36 wt.% of (I2 + 4TBP) and PMII ionic liquid. Such devices produce a maximum efficiency of 6.37% although with slightly lower fill factor. The better performance of DSSC with PMII inclusion in the electrolyte is attributed to the better ionic conductivity of the electrolyte. On the contrary, the addition of GuCN did not boost the performance of the cell. The effect and significance of the additives were explored in this work.