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Incorporating functionalized TiO2 microarchitectures or upconversion nanoparticles (UCNPs) into photoanodes is deemed to be two effective ways to boost the photovoltaic performance of dye-sensitized solar cells (DSSCs). Nonetheless, studies combining functionalized TiO2 and UCNPs for the development of composite photoanode films in DSSCs still remain scarce. In view of this, we present a facile strategy for the design and preparation of a multifunctional composite photoanode containing P25 nanoparticles, peanut-like (PN) TiO2 microstructures, and NaYF4:Yb,Er@NaYF4:Nd@SiO2 core–shell–shell UCNPs. It is found that the DSSC containing a dual-functional photoanode using PN TiO2 as a light-scattering layer and P25 as a transparent layer can achieve a photovoltaic efficiency of 9.01%, presenting a 26.37% enhancement over the blank device. More importantly, the addition of UCNPs can further enhance the photoelectric performance of the DSSC device, realizing an optimal photovoltaic efficiency of 10.58%, one of the highest reported efficiencies for UCNP-based DSSCs with the common N719 photosensitizer. Such a remarkable improvement is mainly due to a synergetic effect of the UCNPs absorbing the near-infrared light and of the PN TiO2 presenting excellent light-scattering potency. Specifically, steady-state experiments reveal that the best-performing device shows only a small efficiency loss after 120 h of testing, exhibiting good device stability. The present work demonstrates the importance of composite photoanodes in enhancing the photovoltaic performances of solar cells.

We report a new strategy to fabricate a multifunctional composite photoanode containing TiO2 hollow spheres (TiO2-HSs), Au nanoparticles (AuNPs) and novel NaYF4 : Yb,Er@NaLuF4 : Eu@SiO2 upconversion nanoparticles (UCNPs). The AuNPs are grown on the photoanode film including TiO2-HSs and UCNPs by a simple in situ plasmonic treatment. As a result, an impressive power conversion efficiency of 14.13 % is obtained, which is a record for N719 dye-based dye-sensitized solar cells, demonstrating great potential for the solar cells toward commercialization. This obvious enhancement is ascribed to a collaborative mechanism of the TiO2-HSs exhibiting excellent light-scattering ability, of the UCNPs converting near-infrared photons into visible photons and of the AuNPs presenting outstanding surface plasmon resonance effect. Notably, a steady-state experiment further reveals that the champion cell exhibits 95.33 % retainment in efficiency even after 180 h of measurements, showing good device stability.

Electrochemistry is a key technology to synthesize, study and scale-up materials and processes for applications in solar energy conversion systems. Mexico has had a tradition of excellence in electrochemistry research and methodology development, and this paper intends to honor some of the key contributors in the subjects of solar energy conversion to useful heat or electricity. We summarize the use of electrochemical techniques as a tool for the deposition and characterization, including the analysis of electrodeposition solutions and deposition mechanisms. In addition, we describe the use of electrodeposited and hybrid ZnO films for application in dye-sensitized solar cells, which are photoelectrochemical systems, and discuss the mechanisms that govern solar cell performance., Special Issue. Tribute to the electrochemical emeritus researchers of SNI

Electrochemistry is a key technology to synthesize, study and scale-up materials and processes for applications in solar energy conversion systems. Mexico has had a tradition of excellence in electrochemistry research and methodology development, and this paper intends to honor some of the key contributors in the subjects of solar energy conversion to useful heat or electricity. We summarize the use of electrochemical techniques as a tool for the deposition and characterization, including the analysis of electrodeposition solutions and deposition mechanisms. In addition, we describe the use of electrodeposited and hybrid ZnO films for application in dye-sensitized solar cells, which are photoelectrochemical systems, and discuss the mechanisms that govern solar cell performance., Special Issue. Tribute to the electrochemical emeritus researchers of SNI

Electrochemistry is a key technology to synthesize, study and scale-up materials and processes for applications in solar energy conversion systems. Mexico has had a tradition of excellence in electrochemistry research and methodology development, and this paper intends to honor some of the key contributors in the subjects of solar energy conversion to useful heat or electricity. We summarize the use of electrochemical techniques as a tool for the deposition and characterization, including the analysis of electrodeposition solutions and deposition mechanisms. In addition, we describe the use of electrodeposited and hybrid ZnO films for application in dye-sensitized solar cells, which are photoelectrochemical systems, and discuss the mechanisms that govern solar cell performance., Special Issue. Tribute to the electrochemical emeritus researchers of SNI

Electrochemistry is a key technology to synthesize, study and scale-up materials and processes for applications in solar energy conversion systems. Mexico has had a tradition of excellence in electrochemistry research and methodology development, and this paper intends to honor some of the key contributors in the subjects of solar energy conversion to useful heat or electricity. We summarize the use of electrochemical techniques as a tool for the deposition and characterization, including the analysis of electrodeposition solutions and deposition mechanisms. In addition, we describe the use of electrodeposited and hybrid ZnO films for application in dye-sensitized solar cells, which are photoelectrochemical systems, and discuss the mechanisms that govern solar cell performance., Special Issue. Tribute to the electrochemical emeritus researchers of SNI

Dye-sensitized solar cells (DSSCs) rely heavily on the counter electrode for their performance, which is responsible for collecting and transferring electrons generated at the photoanode. While platinum (Pt) has traditionally been used as a counter-electrode material, its cost, limited availability, and environmental concerns make it an unsuitable option for large-scale implementation. Iron–nitrogen––carbon (Fe–N–C) catalysts are receiving increasing attention due to their high catalytic activity and low cost. This study aims to investigate the performance of Fe–N–C materials as counter electrodes in DSSCs and assess their potential as a sustainable alternative to currently used platinum. Two different Fe–N–C-based materials have been synthesized using different carbon and nitrogen sources, and their electrochemical behavior has been assessed using current–voltage curves and impedance spectroscopy. The catalyst comprised a higher amount of iron and nitrogen shows higher efficiency and lower charge-transfer resistance due to improved iodide reaction kinetics and proper stability under potential cycling. However, this catalyst shows lower stability under a passive ageing procedure, which requires further clarification. Results provide new insights into the performance of Fe–N–C-based materials in DSSCs and aid in the further development of this promising technology.

Dye-sensitized solar cells (DSSC) mainly uses organic components as an alternative way of light harvesting element to replace the traditional silicon solar cells. Natural dye alternatively is being used as sensitizers to overcome the limitation of inorganic ruthenium dye which contains heavy metal. In this study, DSSC is expected to enhance its optical properties and light absorption by implementing gold (Au) nanoparticles. Various natural and organic sources can be extracted and acted as a photosensitizer to trap solar energy. Fresh Hibiscus Rosa-Sinensis flowers are one of the good candidates to give higher light absorption in DSSC. The characteristics of the dye photosensitizer will be observed under UV-Vis-NIR Spectrophotometer. The efficiency of complete DSSC will be determined by using LIV tester. An attempt to enhance light-harvesting efficiency and hence the light to current conversion efficiency by mixing Au nanoparticles TiO? QUOTE   paste. Au nanoparticle was selected because it can act as a medium between the dye and Ti QUOTE  O? to increase the electron transmission speed. The Hibiscus dye in DSSC achieved an efficiency of 0.14%. However, the efficiency reduced to 0.000178% as Au NPs was added. The effects of the addition of Au nanoparticles are discussed.&nbsp

The TiO2 blocking layer in dye-sensitized solar cells is the most difficult component to evaluate at thicknesses below 50 nm, but it is crucial for the power conversion efficiency. Here, the electrode capacitance of TiO2 blocking layers is tested in aqueous [Fe(CN)6]3–/4– and correlated to the performance of photoanodes in devices based on a [Cu(tmby)2]2+/+ electrolyte. The effects of the blocking layer on electronic recombination in the devices are illustrated with transient photovoltage methods and electrochemical impedance analysis. We have thus demonstrated a feasible and facile method to assess TiO2 blocking layers for the fabrication of dye-sensitized solar cells., Title in Web of Science: Assessment of TiO2 Blocking Layers for Cu-II/I-Electrolyte Dye-Sensitized Solar Cells by Electrochemical Impedance Spectroscopy

The addition of a small organic electron donor, tris(p-anisyl)amine (TPAA), to an iodide/triiodide electrolyte for dye-sensitized solar cells was found to give pronounced effects on charge transfer reactions. When using the organic dye LEG4 as a sensitizer, an improved solar cell performance was found, which could be attributed to the extremely rapid dye regeneration reaction when TPAA is added. In contrast, for the ruthenium dye N719, no significant solar cell improvement was found, despite rapid dye regeneration. Using transient absorption measurements, it was found that reduction of the intermediate TPAA(+) by iodide is sluggish. This allows for significant recombination of electrons in TiO2 to TPAA(+) when the adsorbed dye layer does not have sufficient electron-blocking properties.

The addition of a small organic electron donor, tris(p-anisyl)amine (TPAA), to an iodide/triiodide electrolyte for dye-sensitized solar cells was found to give pronounced effects on charge transfer reactions. When using the organic dye LEG4 as a sensitizer, an improved solar cell performance was found, which could be attributed to the extremely rapid dye regeneration reaction when TPAA is added. In contrast, for the ruthenium dye N719, no significant solar cell improvement was found, despite rapid dye regeneration. Using transient absorption measurements, it was found that reduction of the intermediate TPAA(+) by iodide is sluggish. This allows for significant recombination of electrons in TiO2 to TPAA(+) when the adsorbed dye layer does not have sufficient electron-blocking properties.

The addition of a small organic electron donor, tris(p-anisyl)amine (TPAA), to an iodide/triiodide electrolyte for dye-sensitized solar cells was found to give pronounced effects on charge transfer reactions. When using the organic dye LEG4 as a sensitizer, an improved solar cell performance was found, which could be attributed to the extremely rapid dye regeneration reaction when TPAA is added. In contrast, for the ruthenium dye N719, no significant solar cell improvement was found, despite rapid dye regeneration. Using transient absorption measurements, it was found that reduction of the intermediate TPAA(+) by iodide is sluggish. This allows for significant recombination of electrons in TiO2 to TPAA(+) when the adsorbed dye layer does not have sufficient electron-blocking properties.

The TiO2 blocking layer in dye-sensitized solar cells is the most difficult component to evaluate at thicknesses below 50 nm, but it is crucial for the power conversion efficiency. Here, the electrode capacitance of TiO2 blocking layers is tested in aqueous [Fe(CN)6]3–/4– and correlated to the performance of photoanodes in devices based on a [Cu(tmby)2]2+/+ electrolyte. The effects of the blocking layer on electronic recombination in the devices are illustrated with transient photovoltage methods and electrochemical impedance analysis. We have thus demonstrated a feasible and facile method to assess TiO2 blocking layers for the fabrication of dye-sensitized solar cells., Title in Web of Science: Assessment of TiO2 Blocking Layers for Cu-II/I-Electrolyte Dye-Sensitized Solar Cells by Electrochemical Impedance Spectroscopy

Summary Conventional redox mediators based on metal coordination complexes undergo electron transfer through the change in oxidation state of the metal center. However, electron transfer kinetics are offset toward preferred oxidation states when preorganized ligands constrain the reorganization of the coordination sphere. In contrast, we report here on dimeric copper(II/I) redox couples, wherein the extent of oxidation/reduction of two metal centers dictates the dynamic formation of dimer and monomer complexes: the dimeric (Cu(I))2 transitions to monomers of Cu(II). The bis(thiazole/pyrrole)-bipyridine tetradentate ligands stabilize both oxidation states of the unique redox systems. The dynamic dimer redox mediators offer a viable two-electron redox mechanism to develop efficient hybrid solar cells through inhibited recombination and rapid charge transport. Density functional theory calculations reveal inner reorganization energies for single-electron transfer as low as 0.27 eV, marking the dimeric complexes superior redox systems over single complexes as liquid and potentially solid-state electrolytes.

The TiO2 blocking layer in dye-sensitized solar cells is the most difficult component to evaluate at thicknesses below 50 nm, but it is crucial for the power conversion efficiency. Here, the electrode capacitance of TiO2 blocking layers is tested in aqueous [Fe(CN)6]3–/4– and correlated to the performance of photoanodes in devices based on a [Cu(tmby)2]2+/+ electrolyte. The effects of the blocking layer on electronic recombination in the devices are illustrated with transient photovoltage methods and electrochemical impedance analysis. We have thus demonstrated a feasible and facile method to assess TiO2 blocking layers for the fabrication of dye-sensitized solar cells., Title in Web of Science: Assessment of TiO2 Blocking Layers for Cu-II/I-Electrolyte Dye-Sensitized Solar Cells by Electrochemical Impedance Spectroscopy

In the ambition to improve the power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs), it will be essential to understand the mechanisms and rates of dye regeneration. Although the mechanism of dye regeneration has been studied by static density functional theory (DFT) and classical molecular dynamics (CMD) simulations, ab initio molecular dynamics simulation (aiMD) has the potential to combine the insights from both methods for a deeper understanding. In this work, a series of aiMD simulations has been performed to study the interaction between an oxidized organic model dye, LEG4, and an electrolyte containing iodide ions as reducing agents. Dynamic Mulliken and natural spin population analyses show that two iodide ions, I-center dot center dot center dot I-, are required for dye regeneration. It was found that a distance between I-center dot center dot center dot I(-)of less than 6.5 angstrom at site 1 benefits from the electrostatic environment of the triphenylamine group of the LEG4 dye, and a corresponding distance of 4.8 angstrom at site 2 is essential for the dye regeneration process to take place. The rate constants of the LEG4 regeneration by two iodine ions range from 10(5) to 10(12) s(-1), spanning a window in which results from both experimental and static theoretical calculations fall. It is also verified that the probability of electron transfer from a radical I-2(-) to the oxidized LEG4 dye is extremely low due to the rapid electron back transfer. However, it has been found that the addition of an additional iodide ion at a distance of 5 angstrom with respect to the radical I-2(-) opens the pathway for the reduction of the oxidized LEG4 dye with an associated formation of I-3(-). The current results highlight the necessity for a dynamical approach for a full understanding of the regeneration process., QC 20220315

The addition of a small organic electron donor, tris(p-anisyl)amine (TPAA), to an iodide/triiodide electrolyte for dye-sensitized solar cells was found to give pronounced effects on charge transfer reactions. When using the organic dye LEG4 as a sensitizer, an improved solar cell performance was found, which could be attributed to the extremely rapid dye regeneration reaction when TPAA is added. In contrast, for the ruthenium dye N719, no significant solar cell improvement was found, despite rapid dye regeneration. Using transient absorption measurements, it was found that reduction of the intermediate TPAA(+) by iodide is sluggish. This allows for significant recombination of electrons in TiO2 to TPAA(+) when the adsorbed dye layer does not have sufficient electron-blocking properties.

To develop efficient dye-sensitized solar cells (DSSCs), concerted companion (CC) dyes XW60-XW63 constructed from the covalent linkage of a strapped porphyrin dye unit and an organic dye unit have been reported to exhibit panchromatic absorption and excellent photovoltaic performance. However, these CC dyes only afforded moderate V-OC values of ca. 763 mV, demonstrating relatively weak antiaggregation ability, which remains an obstacle for further enhancing the photovoltaic behavior. To address this problem, we herein develop porphyrin dyes XW77-XW80 with the macrocycles wrapped with alkoxy chains of various lengths (OC6H13-OC22H45) and the corresponding CC dyes XW81-XW84 containing these porphyrin dye units. Interestingly, the new CC dyes XW81-XW83 exhibit increasing V-OC from 745 to 784 mV with the chain lengths extended from C6 to C18, and a lowered V-OC of 762 mV was obtained for XW84 when the chain length was further extended to C22. As a result, XW83 afforded the highest PCE of 12.2%, which is, to the best of our knowledge, the record efficiency for the iodine electrolyte-based solar cells sensitized with a single dye. These results can be rationalized by the so-called doubly concerted companion (DCC) effects, that is, the two subdye units exhibit not only complementary absorption but also concerted antiaggregation with the long wrapping chains on the porphyrins unit simultaneously protecting the porphyrin macrocycle and the neighboring organic subdye unit, thus affording panchromatic absorption and strong antiaggregation and anticharge-recombination ability. These results provide a new approach for constructing a class of DCC dyes to achieve high-performance DSSCs without using any antiaggregating coadsorbent or absorption-enhancing cosensitizer.

In recent years, copper(ii/i) complexes have attracted growing interest as redox mediators in dye-sensitized solar cells. Here, we report a new class of copper complexes bearing a bis(2-pyridylmethyl)-1,2-ethanedithiol ligand, coded as [Cu(N2S2)]2+/+, with tetrafluoroborate ([BF4]-) and hexafluorophosphate ([PF6]-) counterions. Strikingly, it is discovered that the solubility and diffusion coefficients of Cu(i) species are dramatically improved by changing the counterion from [BF4]- to [PF6]-. As a result, DSCs incorporating the latter redox system show a much enhanced short-circuit current density and fill factor, which in turn lead to a superior overall power conversion efficiency (PCE) of 10.3% under one sun illumination (100 mW cm-2, AM 1.5G). This has been the highest PCE reported so far for copper redox mediators with sulfur-coordinating ligands in DSCs. Thus, this work provides an effective strategy for further design of more efficient redox mediators in DSCs., QC 20221114

This study investigates the natural dyes of curcumin and chlorophyll as sensitizers of dye-sensitized solar cells. Mixing two dyes can create a wider absorbance area, thereby increasing the performance of a solar cell. This study used variations in the volume ratio of the chlorophyll and curcumin mixture of 100:0, 75:25, 50:50, 25:75, and 0:100. The results were characterized by cyclic voltammetry, UV-Vis spectrophotometry, and solar simulator. The curcumin–chlorophyll dye mixture exhibited better light absorbance, bandgap energy, and efficiency than those of single dyes. The highest solar cell performance was achieved with a 75:25 mixture of chlorophyll and curcumin with electrical efficiency, short-circuit photocurrent density, open-circuit photovoltage, and fill factor values of 0.261%, 1.20 mA/cm2, 0.535 V, and 0.405, respectively.

Electrochemical impedance spectroscopy (EIS) is a commonly used steady-state technique to examine the internal resistance of electron-transfer processes in solar cell devices, and the results are directly related to the photovoltaic performance. In this study, EIS was performed to study the effects of accelerated ageing, aiming for insights into the degradation mechanisms of dye-sensitized solar cells (DSSCs) containing cobalt tris(bipyridine) complexes as redox mediators. Control experiments based on aged electrolytes differing in concentrations of the redox couple components and cation co-additives were conducted to reveal the correlation of the cell degradation with external and internal properties. The failure modes of the cells emerged as changes in the kinetics of charge- and ion-transfer processes. An insufficient concentration of the redox complexes, in particular Co(iii), was found to be the main reason for the inferior performance after ageing. The related characterization of electrolytes aged outside the solar cell devices confirms the loss of active Co(iii) complexes in the device electrolytes. A new EIS feature at low frequencies emerged during ageing and was analysed. The new EIS feature demonstrates the presence of an unexpected rate-limiting, charge-transfer process in aged devices, which can be attributed to the TiO2/electrolyte interface. High-resolution fluorescence detected X-ray absorption spectroscopy (HERFD-XAS) was performed to identify the reduction of a part of Co(iii) to Co(II) after ageing, by investigating the Co K absorption edge. The HERFD-XAS data suggested a partial reduction of Co(iii) to Co(ii), accompanied by a difference in symmetry of the reduced species., QC 20230508

The TiO2 blocking layer in dye-sensitized solar cells is the most difficult component to evaluate at thicknesses below 50 nm, but it is crucial for the power conversion efficiency. Here, the electrode capacitance of TiO2 blocking layers is tested in aqueous [Fe(CN)6]3–/4– and correlated to the performance of photoanodes in devices based on a [Cu(tmby)2]2+/+ electrolyte. The effects of the blocking layer on electronic recombination in the devices are illustrated with transient photovoltage methods and electrochemical impedance analysis. We have thus demonstrated a feasible and facile method to assess TiO2 blocking layers for the fabrication of dye-sensitized solar cells., Title in Web of Science: Assessment of TiO2 Blocking Layers for Cu-II/I-Electrolyte Dye-Sensitized Solar Cells by Electrochemical Impedance Spectroscopy

The addition of a small organic electron donor, tris(p-anisyl)amine (TPAA), to an iodide/triiodide electrolyte for dye-sensitized solar cells was found to give pronounced effects on charge transfer reactions. When using the organic dye LEG4 as a sensitizer, an improved solar cell performance was found, which could be attributed to the extremely rapid dye regeneration reaction when TPAA is added. In contrast, for the ruthenium dye N719, no significant solar cell improvement was found, despite rapid dye regeneration. Using transient absorption measurements, it was found that reduction of the intermediate TPAA(+) by iodide is sluggish. This allows for significant recombination of electrons in TiO2 to TPAA(+) when the adsorbed dye layer does not have sufficient electron-blocking properties.

Dye-sensitized solar cells (DSSC) mainly uses organic components as an alternative way of light harvesting element to replace the traditional silicon solar cells. Natural dye alternatively is being used as sensitizers to overcome the limitation of inorganic ruthenium dye which contains heavy metal. In this study, DSSC is expected to enhance its optical properties and light absorption by implementing gold (Au) nanoparticles. Various natural and organic sources can be extracted and acted as a photosensitizer to trap solar energy. Fresh Hibiscus Rosa-Sinensis flowers are one of the good candidates to give higher light absorption in DSSC. The characteristics of the dye photosensitizer will be observed under UV-Vis-NIR Spectrophotometer. The efficiency of complete DSSC will be determined by using LIV tester. An attempt to enhance light-harvesting efficiency and hence the light to current conversion efficiency by mixing Au nanoparticles TiO? QUOTE   paste. Au nanoparticle was selected because it can act as a medium between the dye and Ti QUOTE  O? to increase the electron transmission speed. The Hibiscus dye in DSSC achieved an efficiency of 0.14%. However, the efficiency reduced to 0.000178% as Au NPs was added. The effects of the addition of Au nanoparticles are discussed.&nbsp

In this work, carbon xerogels (CXGs) doped with nitrogen or sulfur have been investigated as DSSC counter electrodes. CXGs have been prepared by a sol–gel method from resorcinol and formaldehyde and subsequent carbonization. Nitrogen doping has been carried out by introducing melamine into the synthesis process along with resorcinol and formaldehyde, while sulfur has been incorporated by direct reaction of the carbon material with elemental sulfur. The counter electrodes for DSSCs have been prepared by airbrushing on conductive glass (fluorine-doped tin oxide, FTO), and their electrochemical behavior has been evaluated, observing that the introduction of heteroatoms such as nitrogen or sulfur leads to an improvement in efficiency compared to the undoped material thanks to a decrease in charge transfer resistance.

The TiO2 blocking layer in dye-sensitized solar cells is the most difficult component to evaluate at thicknesses below 50 nm, but it is crucial for the power conversion efficiency. Here, the electrode capacitance of TiO2 blocking layers is tested in aqueous [Fe(CN)6]3–/4– and correlated to the performance of photoanodes in devices based on a [Cu(tmby)2]2+/+ electrolyte. The effects of the blocking layer on electronic recombination in the devices are illustrated with transient photovoltage methods and electrochemical impedance analysis. We have thus demonstrated a feasible and facile method to assess TiO2 blocking layers for the fabrication of dye-sensitized solar cells., Title in Web of Science: Assessment of TiO2 Blocking Layers for Cu-II/I-Electrolyte Dye-Sensitized Solar Cells by Electrochemical Impedance Spectroscopy

Three novel diketopyrrolopyrrole-based metal-free organic dyes (TPh, BPh and SPh) with different pi-bridge lengths were designed and synthesized for dye-sensitized solar cells (DSSCs). The phenyl units were employed as the additional pi-bridge for the three dyes, which located between the diketopyrrolopyrrole core and cyanoacrylic acid unit. Interestingly, it is the first time to report a diketopyrrolopyrmle-based dye with only one additional pi-bridge unit (SPh). The effects of pi-bridge length on photophysical, molecular planarity, energy level and photovoltaic properties of the dyes were systematically investigated. The results revealed that the prolongation of pi-bridge length by introducing an additional phenyl unit results in an extra torsion in the structural framework and reduces the molecule planarity, which has a negative impact on improving the light-harvesting ability, while it is beneficial in lowering the tendency of aggregation and enhancing the excited electron injection efficiency. Finally, with a moderate pi-bridge length (BPh), the best balance of overall performances is achieved, resulting in the highest power conversion efficiency (6.57%) without chenodeoxycholic acid.

Three novel push-pull dyes, with carbazole donors, codedAJ502,TZ101andTZ102are synthesized and applied as co-sensitizers in dye-sensitized solar cells (DSSCs).TZ101andTZ102have similar structures except for two fluorine atoms introduced on the benzotriazole (BTZ) unit.AJ502shows a near-IR absorption spectrum that is suitable for co-sensitization withTZ101andTZ102. The co-sensitized DSSC device based onCO-1(AJ502 : TZ101= 3 : 4 (0.075 mM : 0.1 mM)) achieves a power conversion efficiency (PCE) of 10.3% under AM 1.5G irradiation, with 1.06 V open-circuit voltage (Voc), 13.75 mA cm−2short-circuit photocurrent density (Jsc), and 70.8% fill factor (FF), a significant improvement compared to the single dye, 6.0% forAJ502and 5.1% forTZ101with a copper(i/ii)-based redox electrolyte. A PCE of 8.9% is also obtained by devices based onCO-2(AJ502 : TZ102= 3 : 4). ForCO-1, the fluorine atoms inTZ101play a critical role by widening the active light capturing bands of bothTZ101andAJ502on the TiO2film whileTZ102andAJ502show weaker interaction under the same conditions. The UV-vis spectrum and Raman spectrum revealed thatAJ502can form supramolecules withTZ101andTZ102formed on the TiO2film., QC 20220316

In recent years, copper redox mediators have attracted growing interest in dye-sensitized solar cells (DSCs). However, experiments revealed that ubiquitously used Lewis-base additives in the electrolytes coordinate to the CuII species, which restricts further enhancement of device performance and stability. We report the application of copper complexes endowed with diamine-tripyridine pentadentate ligands, [Cu(tpe)]2+/+ (tpe=N-benzyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethylenediamine) and [Cu(tme)]2+/+ (tme=N-benzyl-N,N′,N′-tris(6-methylpyridin-2-ylmethyl)ethylenediamine), as redox mediators in DSCs. Experimental measurements demonstrate that the coordination environment of Cu(II) complexes with pentadentate ligands remains unchanged in the presence of TBP, which is in stark contrast to the state-of-the-art bipyridyl counterpart. DSCs based on [Cu(tme)]2+/+ complexes exhibit an excellent long-term stability and maintain more than 90 % of the initial efficiency after 400 h under continuous illumination, which outperform the reference devices incorporating the bipyridyl counterpart (less than 80 %) under identical conditions., QC 20220318

Dye-sensitized solar cells (DSSCs) or Grätzel cells are electrochemical devices in where physicochemical properties of different materials are combined to obtain electric energy. These photoconversion devices have evolved from a pioneering concept of molecular photovoltaics to industrial development with confirmed record efficiencies of 14.3%. Their efficiency combined with low-cost production methods and a high aesthetic interest enables the production of DSSC products for consumer electronics market. The strengths of this technology and the fact that its drawbacks are not limiting for this application makes consumer electronics and DSSC a perfect match for the development of self-powered devices. Some companies have already spot a potential market and are currently launching different consumer electronics and other devices with embedded DSSC. This thesis provides an overview of the operation principles of DSSC and the possible routes to improve the efficiency of these devices to emerge and thrive. Additionally, improvements in efficiency, stability and manufacturing needed to be addressed in the near future for this technology are discussed and its suitability to represent a breakthrough in the market of consumer electronics. An overview of the main companies developing DSSC and current prototypes and products is included.

Upconversion (UC) technology makes it possible to harvest infrared (IR) light from the sun and has increasingly been employed in recent years to improve the efficiency of solar cells. The progress in the area concerns both research on fundamental principles and processes of UC and technologies of device fabrication. Significant increase of important solar cell parameters, like short-circuit photocurrent density and open-circuit photovoltage as well as the total photon-to-current efficiency, has been accomplished. We here review the research published during the last few years in the area, in particular we consider the two most cherished techniques, namely the incorporation of upconverting nanophosphors directly into the photoanodes of the solar cells and the introduction of plasmonic metal nanoparticles co-existing with the UC particles. Other ways to achieve strong field enhancement, and the use of the non-linear nature of UC, is to apply microlenses, with or without assisting plasmonic excitation. Further enhanced UC action has been demonstrated by broad band and effective harvesting by organic IR antennas, with subsequent mediation by an intermediate nanoshell of the energy into the upconverting core. Codoping, nanohybrid and layer-by-layer technologies involving upconverting particles as well as the use of upconverting nanoparticles in hole-transport and electrolyte layers, tested in recent works, are also reviewed. While most of these technologies employ upconverting rare earth metals for sequential photon absorption, the main alternative technique, namely triplet-triplet annihilation UC using organic materials, is also reviewed. It is our belief that all these approaches will be further much researched in the near future, with potentially great impact on solar cell technology.

Redox mediators play a major role in determining the photocurrent and photovoltage in dye-sensitized solar cells (DSSCs). Copper complexes are a good option for redox mediators but suffer from electron recombination. The traditional method is to add 4-(tert-butyl)pyridine (TBP) to the electrolyte, which is coordinated with the empty orbit of Ti, thereby slowing down the oxidized mediator's ability to capture electrons. However, this strategy will result in competitive coordination between the redox mediator and TBP, decreasing the stability of the device. In this study, two helical copper(I) complexes are synthesized and applied to TBP-free solar cells. La (1,3-bis(2,2'-bipyridin-6-yloxy)propane) and Lb (1,3-bis[(6'-methyl-2,2'-bipyridin-6-yl)oxy]propane) tend to form double-stranded helicates ([Cu-2(Ln)(2)](2+), n = a, b) rather than mononuclear complexes ([Cu(Ln)](+), n = a, b). To facilitate quantitative analysis of the complexes, Cu(I)Ln and Cu(II)Ln (n = a, b) are used as molecular formulae. (CuLa)-La-I and Cu(I)Lb are characterized by electrospray mass spectroscopy, H-1 NMR spectroscopy, and electrochemistry. J-V measurement shows that both V-oc and J(sc) increase with the increase of (CuLa)-La-I concentration (below 0.1 M), and the best power conversion efficiency is 8.2%. The relationship between Cu(I) concentration and recombination for further study was measured by IMVS., QC 20210601

A series of asymmetric and symmetric 1,3-dialkyltriazolium iodides were studied with hindsight to their application as electrolytes and redox mediators in dye-sensitized solar cells (DSSCs). Compounds with an alkyl chain length from C4 to C10 present the characteristics of ionic liquids (ILs), whilst those with longer chains exhibit liquid crystallinity. All compounds show an appreciable chemical and thermal stability with decomposition temperatures around 185–195 °C. Testing these compounds as electrolytes and redox mediators in DSSCs reveals significant changes in the properties of the electrolyte upon addition of the redox couple. Addition of iodine generally leads to a depression of the melting point and an enhancement of conductivity. These changes in the electrolyte, which are significant, have so far been largely overlooked in DSSC optimization. Furthermore, in comparison to frequently employed imidazolium iodides, 1-alkyl-3-methyltriazolium iodides show both an improved superior efficiency and an extended cell lifetime. This is attributed to the fact that, unlike the imidazolium salts, the triazolium counterparts are not hygroscopic. The nonhygroscopic nature of the salts also renders device fabrication easier. In addition, electrode passivation, which is commonly observed with imidazolium iodides, could not be noticed for the triazolium analogues, making these materials overall extremely attractive.

The charge-transport dynamics at the dye-TiO2interface plays a vital role for the resulting power conversion efficiency (PCE) of dye sensitized solar cells (DSSCs). In this work, we have investigated the charge-exchange dynamics for a series of organic dyes, of different complexity, and a small model of the semiconductor substrate TiO2. The dyes studied involve L1, D35 and LEG4, all well-known organic dyes commonly used in DSSCs. The computational studies have been based onab initiomolecular dynamics (aiMD) simulations, from which structural snapshots have been collected. Estimates of the charge-transfer rate constants of the central exchange processes in the systems have been computed. All dyes show similar properties, and differences are mainly of quantitative character. The processes studied were the electron injection from the photoexcited dye, the hole transfer from TiO2to the dye and the recombination loss from TiO2to the dye. It is notable that the electronic coupling/transfer rates differ significantly between the snapshot configurations harvested from the aiMD simulations. The differences are significant and indicate that a single geometrically optimized conformation normally obtained from static quantum-chemistry calculations may provide arbitrary results. Both protonated and deprotonated dye systems were studied. The differences mainly appear in the rate constant of recombination loss between the protonated and the deprotonated dyes, where recombination losses take place at significantly higher rates. The inclusion of lithium ions close to the deprotonated dye carboxylate anchoring group mitigates recombination in a similar way as when protons are retained at the carboxylate group. This may give insight into the performance-enchancing effects of added salts of polarizing cations to the DSSC electrolyte. In addition, solvent effects can retard charge recombination by about two orders of magnitude, which demonstrates that the presence of a solvent will incr, QC 20220826

The role of the counter electrode in the dye-sensitized solar cell (DSSC) mechanism is to collect the electrons received from the external circuit, and mainly to catalyse the reduction of tri-iodide ions in the electrolyte system. The faster tri-iodide reduction, the faster oxidized dye molecules are regenerated, and thus better DSSC performance. Typically, a platinum catalyst layer is used as a counter electrode in DSSC due to its high conductivity, stability and electrocatalytic activity. However, platinum is a rare and expensive material which prohibit its application for mass production of DSSC. It also corrodes when exposed to the iodine-based electrolyte, which therefore affect the longterm stability of the cell. For the aim of DSSC commercialization, extensive researches have been conducted to reduce the cost of DSSC by introducing effective and low-cost alternative materials. Carbon-based materials DSSC counter electrodes have attracted great interest as alternatives for Pt due to their low-cost, conductivity, catalytic activity, and chemical stability. Recently, owing to its superior electrical conductivity and high crystallinity, graphene was studied as DSSC counter electrode. Though, its catalytic activity for tri-iodide reduction is still considered low. The carbon black also exhibits high electrical conductivity, but with high electrocatalytic activity for tri-iodide reduction due to its higher surface area. Thus, it is expected that Graphene/ Carbon black composites would show higher catalytic activity and better performance as DSSC counter electrode and being promising alternative to replace the expensive platinum in DSSCs. This research started with optimization of the single-layer screen-printed TiO2 photoanode, and then is intended to investigate the application of low-cost and effective Graphene and Graphene/Carbon black (G/Cb) composites counter electrodes for DSSC. Graphene counter electrodes were prepared by drop-casting the diluted graphene di

In many countries modern solar greenhouses that were developed by incorporating solar Photovoltaic (PV) (crystalline silicon based) into the agricultural greenhouses are currently being implemented. With this development, farmers will be able to generate income from both agricultural activity output and electrical generation. However, the most challenges manifested by PV greenhouses are to strike a balance between PV roofs and plants since conventional PV (Si based) is opaque to sunlight. The distribution of sunshades by PV panels above the greenhouse follows a linear correlation with the cover ratio. Therefore, semi-transparent DSSC; third generation of solar PV cells is the perfect choice in greenhouse application due to its unique characteristics such as various colour and transparency, versatility in scaling and low fabrication cost. In addition, DSSC's specific colour (determined by the dye) can serve as a plant growth regulator or photoselective shading that adsorbs and manipulates the greenhouse spectral irradiation. The Dynamic Dye-sensitized solar cell Mini Greenhouse (DDMG) has been developed and fabricated to maximize the use of light (PAR wavelength) that is important to the plant photosynthesis process, while the other wavelengths are used to generate electricity. The field test was carried out to determine DDMG's performance by means of examining Misai Kucing's sustainability within this prototype. To assess the effects and contributing factors, microclimate parameters such as temperature, relative humidity (RH), Vapour Pressure Deficit (VPD) and Photosynthetic Photon Flux Density (PPFD) were measured. To determine the feasibility of the DDMG, the experimental data were compared with the glass greenhouse as control. From the experiment and findings, it is observed that the performance of DDMG is related to internal microclimate greenhouse which is consequently affect the sustainability and growth of Misai Kucing cultivated in this prototype. From this

Dye-sensitized solar cells (DSSCs) or Grätzel cells are electrochemical devices in where physicochemical properties of different materials are combined to obtain electric energy. These photoconversion devices have evolved from a pioneering concept of molecular photovoltaics to industrial development with confirmed record efficiencies of 14.3%. Their efficiency combined with low-cost production methods and a high aesthetic interest enables the production of DSSC products for consumer electronics market. The strengths of this technology and the fact that its drawbacks are not limiting for this application makes consumer electronics and DSSC a perfect match for the development of self-powered devices. Some companies have already spot a potential market and are currently launching different consumer electronics and other devices with embedded DSSC. This thesis provides an overview of the operation principles of DSSC and the possible routes to improve the efficiency of these devices to emerge and thrive. Additionally, improvements in efficiency, stability and manufacturing needed to be addressed in the near future for this technology are discussed and its suitability to represent a breakthrough in the market of consumer electronics. An overview of the main companies developing DSSC and current prototypes and products is included.

During the last 20 years, the scientific community has shown growing interest towards carbonaceous nanomaterials due to their appealing mechanical, thermal, and optical features, depending on the specific nanoforms. Among these, graphene quantum dots (GQDs) recently emerged as one of the most promising nanomaterials due to their outstanding electrical properties, chemical stability, and intense and tunable photoluminescence, as it is witnessed by a booming number of reported applications, ranging from the biological field to the photovoltaic market. To date, a plethora of synthetic protocols have been investigated to modulate the portfolio of features that GQDs possess and to facilitate the use of these materials for target applications. Considering the number of publications and the rapid evolution of this flourishing field of research, this review aims at providing a broad overview of the most widely established synthetic protocols and offering a detailed review of some specific applications that are attracting researchers’ interest.

The role of the counter electrode in the dye-sensitized solar cell (DSSC) mechanism is to collect the electrons received from the external circuit, and mainly to catalyse the reduction of tri-iodide ions in the electrolyte system. The faster tri-iodide reduction, the faster oxidized dye molecules are regenerated, and thus better DSSC performance. Typically, a platinum catalyst layer is used as a counter electrode in DSSC due to its high conductivity, stability and electrocatalytic activity. However, platinum is a rare and expensive material which prohibit its application for mass production of DSSC. It also corrodes when exposed to the iodine-based electrolyte, which therefore affect the longterm stability of the cell. For the aim of DSSC commercialization, extensive researches have been conducted to reduce the cost of DSSC by introducing effective and low-cost alternative materials. Carbon-based materials DSSC counter electrodes have attracted great interest as alternatives for Pt due to their low-cost, conductivity, catalytic activity, and chemical stability. Recently, owing to its superior electrical conductivity and high crystallinity, graphene was studied as DSSC counter electrode. Though, its catalytic activity for tri-iodide reduction is still considered low. The carbon black also exhibits high electrical conductivity, but with high electrocatalytic activity for tri-iodide reduction due to its higher surface area. Thus, it is expected that Graphene/ Carbon black composites would show higher catalytic activity and better performance as DSSC counter electrode and being promising alternative to replace the expensive platinum in DSSCs. This research started with optimization of the single-layer screen-printed TiO2 photoanode, and then is intended to investigate the application of low-cost and effective Graphene and Graphene/Carbon black (G/Cb) composites counter electrodes for DSSC. Graphene counter electrodes were prepared by drop-casting the diluted graphene di

In many countries modern solar greenhouses that were developed by incorporating solar Photovoltaic (PV) (crystalline silicon based) into the agricultural greenhouses are currently being implemented. With this development, farmers will be able to generate income from both agricultural activity output and electrical generation. However, the most challenges manifested by PV greenhouses are to strike a balance between PV roofs and plants since conventional PV (Si based) is opaque to sunlight. The distribution of sunshades by PV panels above the greenhouse follows a linear correlation with the cover ratio. Therefore, semi-transparent DSSC; third generation of solar PV cells is the perfect choice in greenhouse application due to its unique characteristics such as various colour and transparency, versatility in scaling and low fabrication cost. In addition, DSSC's specific colour (determined by the dye) can serve as a plant growth regulator or photoselective shading that adsorbs and manipulates the greenhouse spectral irradiation. The Dynamic Dye-sensitized solar cell Mini Greenhouse (DDMG) has been developed and fabricated to maximize the use of light (PAR wavelength) that is important to the plant photosynthesis process, while the other wavelengths are used to generate electricity. The field test was carried out to determine DDMG's performance by means of examining Misai Kucing's sustainability within this prototype. To assess the effects and contributing factors, microclimate parameters such as temperature, relative humidity (RH), Vapour Pressure Deficit (VPD) and Photosynthetic Photon Flux Density (PPFD) were measured. To determine the feasibility of the DDMG, the experimental data were compared with the glass greenhouse as control. From the experiment and findings, it is observed that the performance of DDMG is related to internal microclimate greenhouse which is consequently affect the sustainability and growth of Misai Kucing cultivated in this prototype. From this

Copper coordination complexes have emerged as a group of transition metal complexes that play important roles in solar energy conversion, utilization and storage, and have the potential to replace the quintessential commonly used transition metals, like Co, Pt, Ir and Ru as light sensitizers, redox mediators, electron donors and catalytic centers. The applications of copper coordination compounds in chemistry and energy related technologies are many and demonstrate their rightful place as sustainable, low toxicity and Earth-abundant alternative materials. In this perspective we show the most recent impact made by copper coordination complexes in dye-sensitized solar cells and other energy relevant applications., De två första författarna delar förstaförfattarskapet

Increasing attention has been paid on solar energy conversion since the abundant solar energy possesses the potential to solve the problems on energy crisis and climate change. Dye-sensitized mesoporous NiO film was developed as one of the attractive photocathodes to fabricate p-type dye-sensitized solar cells (p-DSCs) and dye-sensitized photoelectrosynthetic cells (p-DSPECs) for electricity and chemical fuels generation, respectively. In this thesis, we designed a well-structured NiO-dye-TiO2 configuration by an atomic layer deposition (ALD) technique, with an organic dye PB6 as the photosensitizer. From kinetic studies of charge separation, ultrafast hole injection (< 200 fs) was observed from the excited state of PB6 dye into the valence band of NiO; dye regeneration (electron injection) was in t1/2 ≤ 500 fs, which is the fastest reported in any DSCs. On the basis of NiO-dye-TiO2 configuration, we successfully fabricated solid-state p-type DSCs (p-ssDSCs). Insertion of an Al2O3 layer was adopted to reduce charge recombination, i.e. NiO-dye-Al2O3-TiO2. Theoretically, such a configuration is possible to maintain efficient charge separation and depressed charge recombination. Based on NiO-dye-Al2O3-TiO2 configuration, the open-circuit voltage was improved to 0.48 V. Replacing electron conductor TiO2 with ZnO, short-circuit current density was increased to 680 μA·cm-2. The photocatalytic current density for H2 evolution was improve to 100 μA·cm-2 with a near unity of Faraday efficiency in p-DSPECs. However, to further improve the performance of p-DSCs is very challenging. In p-ssDSCs, the limitation was confirmed from the poor electronically connection of the electron conductor (TiO2 or ZnO) inside the NiO-dye films. We further investigated the electronic property of surface states on mesoporous NiO film. We found that the surface sates, not the bulk, on NiO determined the conductivity of the mesoporous NiO films. The dye regeneration in liquid p-DSCs with I-/I3

The state-of-the-art cobalt(II/III) tris(bipyridyl) redox shuttles open a chapter for pursuing highly efficient dye-sensitized solar cells (DSSCs). Previous work has demonstrated that light exposure of the Co(III) along with the Lewis base additive, tert-butylpyridine (TBP), effectively improves the solar cell efficiency. With this as a platform, a new Lewis base, i.e., tert-butylpyridine N-oxide (TBP-O), is introduced as an electrolyte co-additive instead of TBP alone. The resulting D3S-sensitized solar cells exhibit an efficiency of 6.6% at full solar illumination, which further increases to 8.1% by exposing the new electrolyte mixture to the light and thus outperforms typical Li+-containing DSSCs. A mechanism with regard to the interactions between Co(III) and Lewis base additives supported by electrochemical and spectroscopic studies is suggested to explain the performance improvement. The study illustrates negative effects of TBP on the charge- and mass-transfer kinetics at the electrode/electrolyte interface and reveals that the effects are eliminated by a light-induced reaction between Co(III) and TBP-O., QC 20200729.QC 20210917.

Copper redox mediators have enabled open-circuit voltages (V-OC) of over 1.0 V in dye-sensitized solar cells (DSCs) and have helped to establish DSCs as the most promising solar cell technology in low-light conditions. The addition of additives such as 4-tert-butylpyridine (tBP) to these electrolytes has helped in achieving high solar cell performances. However, emerging evidence suggests that tBP coordinates to the Cu(II) species and limits the performance of these electrolytes. To date, the implications of this coordination are poorly understood. Here, the importance of Lewis base additives for the successful implementation of copper complexes as redox mediators in DSCs is demonstrated. Two redox couples, [Cu(dmp)(2)](+/2+)and [Cu(dpp)(2)](+/2+)(with dmp = 2,9-dimethyl-1,10-phenanthroline and dpp = 2,9-diphenyl-1,10-phenanthroline) in combination with three different Lewis bases, TFMP (4-(trifluoromethyl)pyridine), tBP, and NMBI (1-methyl-benzimidazole), are considered. Through single-crystal X-ray diffraction analysis, absorption, and(1)H-NMR spectroscopies, the coordination of Lewis bases to the Cu(II) centers are studied. This coordination efficiently suppresses recombination losses and is crucial for high performing solar cells. If, however, the coordination involves a ligand exchange, as is the case for [Cu(dpp)(2)](+/2+), the redox mediator regeneration at the counter electrode is significantly retarded and the solar cells show current limitations.

Increasing attention has been paid on solar energy conversion since the abundant solar energy possesses the potential to solve the problems on energy crisis and climate change. Dye-sensitized mesoporous NiO film was developed as one of the attractive photocathodes to fabricate p-type dye-sensitized solar cells (p-DSCs) and dye-sensitized photoelectrosynthetic cells (p-DSPECs) for electricity and chemical fuels generation, respectively. In this thesis, we designed a well-structured NiO-dye-TiO2 configuration by an atomic layer deposition (ALD) technique, with an organic dye PB6 as the photosensitizer. From kinetic studies of charge separation, ultrafast hole injection (< 200 fs) was observed from the excited state of PB6 dye into the valence band of NiO; dye regeneration (electron injection) was in t1/2 ≤ 500 fs, which is the fastest reported in any DSCs. On the basis of NiO-dye-TiO2 configuration, we successfully fabricated solid-state p-type DSCs (p-ssDSCs). Insertion of an Al2O3 layer was adopted to reduce charge recombination, i.e. NiO-dye-Al2O3-TiO2. Theoretically, such a configuration is possible to maintain efficient charge separation and depressed charge recombination. Based on NiO-dye-Al2O3-TiO2 configuration, the open-circuit voltage was improved to 0.48 V. Replacing electron conductor TiO2 with ZnO, short-circuit current density was increased to 680 μA·cm-2. The photocatalytic current density for H2 evolution was improve to 100 μA·cm-2 with a near unity of Faraday efficiency in p-DSPECs. However, to further improve the performance of p-DSCs is very challenging. In p-ssDSCs, the limitation was confirmed from the poor electronically connection of the electron conductor (TiO2 or ZnO) inside the NiO-dye films. We further investigated the electronic property of surface states on mesoporous NiO film. We found that the surface sates, not the bulk, on NiO determined the conductivity of the mesoporous NiO films. The dye regeneration in liquid p-DSCs with I-/I3

Copper coordination complexes have emerged as a group of transition metal complexes that play important roles in solar energy conversion, utilization and storage, and have the potential to replace the quintessential commonly used transition metals, like Co, Pt, Ir and Ru as light sensitizers, redox mediators, electron donors and catalytic centers. The applications of copper coordination compounds in chemistry and energy related technologies are many and demonstrate their rightful place as sustainable, low toxicity and Earth-abundant alternative materials. In this perspective we show the most recent impact made by copper coordination complexes in dye-sensitized solar cells and other energy relevant applications., De två första författarna delar förstaförfattarskapet

Copper coordination complexes have emerged as a group of transition metal complexes that play important roles in solar energy conversion, utilization and storage, and have the potential to replace the quintessential commonly used transition metals, like Co, Pt, Ir and Ru as light sensitizers, redox mediators, electron donors and catalytic centers. The applications of copper coordination compounds in chemistry and energy related technologies are many and demonstrate their rightful place as sustainable, low toxicity and Earth-abundant alternative materials. In this perspective we show the most recent impact made by copper coordination complexes in dye-sensitized solar cells and other energy relevant applications., De två första författarna delar förstaförfattarskapet

Dye-sensitized solar cell (DSSC) which is the third-generation solar cell that utilized dye molecules to absorb light and convert it to electrical energy has a promising efficiency with the ongoing research worldwide. Many implementations have been made through various substitution for materials, optimization on electrodes and assembly of the devices. Since the conventional solid-state DSSC is very rigid to the shape, therefore, the flexible DSSC was introduced. In this study, the flexible photoanode electrode was used to replace the FTO/glass as photoanode electrode. The flexible substrate used is indium tin oxide/polyethylene terephthalate (ITO/PET). However due to its character as a polymer, the limit sintering temperature is 150 ºC and it could not withstand the high temperature of 450 ºC, which is needed for the titanium dioxide (TiO2) photoanode deposited on electrode to remove the binder used inside the paste, ensuring the particles between the TiO2 is porous and enhance the mobility of electrons generated by N719 dye. Therefore, the free binder TiO2 paste was introduced and deposited using doctor blade method, sintered at 120 ºC for 24 hours. However, the efficiency obtained is only 0.07 % which is due to due to weak adhesion to the substrate. Another approach of using flexible titanium (Ti) foil substrate is proposed to overcome the intolerance of high temperature of the ITO/PET as it could stand temperature of more than 450 ºC, lightweight and flexible at some degree which is suitable to substitute the ITO/PET. Since it is opaque, the back- illumination technique has been introduced. To improvise the performance, the optimization of the device was done by optimizing the thickness of the TiO2 photoanode at 15.09 μm and N719 dye loading time for 45 hours. The thickness of the TiO2 leads to better adsorption of dye N719 to collect photons and transfer the electrons while the thickness of Pt counter electrode optimized at volume of 50 µL with thickness of 10 n

High electron-injection efficiency is important for further development of dye-sensitized solar cells (DSSCs). Different electron acceptors have different electron-injection capabilities, which affect device performance. Herein, the effects of two organic triazatruxene (TAT)-based donor-pi-bridge-acceptor sensitizers applied in DSSCs are reported. The sensitizers have either rigid 4-ethynyl benzoic acid (EBA) or Z-type cyanoacrylic acid (CA) as their electron acceptor, denoted as ZL003 and ZL005, respectively. Time-resolved photoluminescence (TR-PL) spectroscopy is applied to reveal the electron transfer dynamics between the sensitizers and TiO2 films. Notably, ZL003 has higher electron-injection efficiency compared with that of ZL005, which is consistent with the higher efficiency and photocurrent of devices based on the former. The dye loading of ZL003 is nearly twice as great as that of ZL005, which accounts for the lower photocurrent of the device. The charge recombination lifetimes for the two dyes are consistent with their open-circuit voltage. Consequently, the ZL003-based devices achieve a higher power conversion efficiency of 13.4% compared with only 7.2% for ZL005., QC 20210902

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