Sensitizers For Solar Cells Research Articles

Calcium-doped TiO2 microspheres and near-infrared carbazole-based sensitizer for efficient co-sensitized dye-sensitized solar cell

Here, we synthesized metal-free organic dye (CCPICPB) with two carbazole donor groups and two anchoring groups that exhibit a panchromatic absorption in the near-infrared range of up to 750 nm. To study the photophysical properties of synthesized CCPICPB dye, the UV–Vis and cyclic voltammetric experiments were studied and the obtained results were validated with theoretical simulation studies. After that, the solvothermal approach is used to synthesize pristine anatase and calcium (Ca)-doped TiO2 microspheres with a smooth morphology. These microstructures are examined in depth using XRD, electron microscopy and electrochemical analysis methods. On TiO2 and Ca-doped TiO2 photoanode materials, we first evaluated the performance of CCPICPB dye. Upon our optimized experimental condition, the 3% Ca-TiO2 photoanode-based device exhibits an efficiency of 4.04%, which is greater than that of the pristine TiO2 photoanode-based device (2.93%). Because of the quicker electron transport in the Ca-TiO2 film, the short-circuit current density and efficiency of DSSCs were improved. Moreover, when the CCPICPB dye was used as a co-sensitizer with the common Ru(II) dye (Z907), interestingly it showed the highest efficiency (6.11%) when compared with Z907 alone (5.12%). This improved efficiency of the co-sensitized device resulted from greater VOC conjugated with improved JSC. The JSC was improved because CCPICB dye could compensate for the photocurrent loss caused by redox electrolyte while the VOC was improved because electron recombination was inhibited under the co-sensitization conditions.Graphical abstract

Prickly Pear Fruit Extract: Capping Agent for the Sol–Gel Synthesis of Discrete Titanium Dioxide Nanoparticles and Sensitizer for Dye-Sensitized Solar Cell

Plant extracts have been utilized as an ecofriendly natural reducing agent for the synthesis of nanomaterials, including metal oxides. Prickly pear (opuntia) fruit extract (PPE) was used as a reducing agent for the sol–gel synthesis of titanium dioxide nanoparticles (TiO2 NPs) and as a sensitizer for the TiO2 NPs photoanode used in dye-sensitized solar cells (DSSCs). Ultraviolet-visible and infrared spectra, X-ray diffraction patterns, and scanning electron microscopic images were confirmed in the formation of semiconducting TiO2 NPs with the predominate size of ~300 nm. The use of PPE rendered discrete TiO2 NPs, whereas the typical synthesis without PPE resulted TiO2 aggregates. TiO2 NPs had a tetragonal crystalline structure, and their grain size was varied with respect to the concentration of PPE. The size of TiO2 crystallites was found to be 20, 19, 15, and 10 nm when the volume percentage of PPE was 0.2, 0.4, 0.6, and 0.8%, respectively. TiO2 NPs obtained using PPE were coated on indium-doped tin oxide substrates and sensitized with natural dye made up of PPE and synthetic dyes, namely rose Bengal (RB) and eosin yellow (EY). The photoanode fabricated with dye-sensitized TiO2 NPs was subjected to current–voltage response studies. The maximum power-conversion efficiency, 1.4%, was recorded for photoanodes sensitized with PPE dye, which is considerably higher than that for RB (1.16%) or EY (0.8%). Overall, the above findings proved that PPE can be used as a potential reducing/capping agent and TiO2 sensitizer for DSSC applications.

Synthesis and Photovoltaic Properties of Simple Fluorene-Based Triphenylamine Metal-Free Organic Sensitizers for Dye-Sensitized Solar Cells

Synthesis and Photovoltaic Properties of Simple Fluorene-Based Triphenylamine Metal-Free Organic Sensitizers for Dye-Sensitized Solar Cells

Optoelectronic Study of Polymer Electrolyte Incorporated Perovskite Sensitized Solar Cell

AbstractPerovskite solar cells have appeared as a leading next‐generation photovoltaic technology. However, notwithstanding rolling efficiencies, many questions remain unreciprocated regarding the mechanisms and performance of the operation. Solution‐processed organic‐inorganic hybrid perovskites have fascinated attention as light‐harvesting materials for perovskite solar cells and photonic applications. The present study focuses on the optical and electronic study of CH3NH3PbBr3 and CH3CH2NH3PbI3 perovskite fabricated by a one‐step solution‐based self‐assemblage method. It is seen that in this study, methyl group represents a better performance than ethyl‐based perovskite‐sensitized solar cells (PSSCs). All the studies centralize on electro‐optical properties of efficient CH3CH2NH3PbI3 and CH3CH2NH3PbI3 PSSC based on polymer electrolytes. It has also characterized lab synthesized perovskite samples by scanning electron microscopy (SEM), UV–vis spectrophotometer, and photovoltaic performance of lab fabricated PSSC is measured by Keithley 2400 resource meter. These findings establish systematic strategy rules to attain silicon‐like efficiencies in simple perovskite solar cells.

Understanding Charge Dynamics in Dense Electronic Manifolds in Complex Environments.

Photoinduced charge transfer (CT) excited states and their relaxation mechanisms can be highly interdependent on the environment effects and the consequent changes in the electronic density. Providing a molecular interpretation of the ultrafast (subpicosecond) interplay between initial photoexcited states in such dense electronic manifolds in condensed phase is crucial for improving and understanding such phenomena. Real-time time-dependent density functional theory is here the method of choice to observe the charge density, explicitly propagated in an ultrafast time domain, along with all time-dependent properties that can be easily extracted from it. A designed protocol of analysis for real-time electronic dynamics to be applied to time evolving electronic density related properties to characterize both in time and in space CT dynamics in complex systems is here introduced and validated, proposing easy to be read cross-correlation maps. As case studies to test such tools, we present the photoinduced charge-transfer electronic dynamics of 5-benzyluracil, a mimic of nucleic acid/protein interactions, and the metal-to-ligand charge-transfer electronic dynamics in water solution of [Ru(dcbpy)2(NCS)2]4-, dcbpy = (4,4'-dicarboxy-2,2'-bipyridine), or "N34-", a dye sensitizer for solar cells. Electrostatic and explicit ab initio treatment of solvent molecules have been compared in the latter case, revealing the importance of the accurate modeling of mutual solute-solvent polarization on CT kinetics. We observed that explicit quantum mechanical treatment of solvent slowed down the charge carriers mobilities with respect to the gas-phase. When all water molecules were modeled instead as simpler embedded point charges, the electronic dynamics appeared enhanced, with a reduced hole-electron distance and higher mean velocities due to the close fixed charges and an artificially increased polarization effect. Such analysis tools and the presented case studies can help to unveil the influence of the electronic manifold, as well as of the finite temperature-induced structural distortions and the environment on the ultrafast charge motions.

Investigation of bacterial pigment from Serratia nematodiphila as a sensitizer for a nanostructured solar cell

Investigation of bacterial pigment from Serratia nematodiphila as a sensitizer for a nanostructured solar cell

New heteroleptic 1,2-bis(diphenylphosphino)ethane appended cobalt(iii) ferrocene dithiocarbamates as sensitizers in dye-sensitized solar cells (DSSCs)

Three new dppe appended heteroleptic cobalt(iii) ferrocenyl dithiocarbamate complex cations were synthesized and used as sensitizers in DSSCs.

Effect of nickel doping on the spectral sensitivity of silicon solar cells

In the modern industrial production of solar cells (SC), there is a growing trend to utilize “solar silicon” as the base material due to its cost-effectiveness. However, solar silicon possesses a drawback - it has a shorter lifetime of minority charge carriers (MCC), making it challenging to achieve high efficiency in solar cells. To address this limitation and improve the efficiency of solar cells based on “solar silicon,” two key objectives need to be met. Firstly, it is essential to increase the lifetime of photogenerated charge carriers. Secondly, there is a need to minimize both optical and electrical energy losses. To achieve an increase in the lifetime of minority charge carriers in SCs, a process called gettering can be employed. This process involves utilizing clusters of nickel atoms to trap uncontrolled impurity atoms. The paper presents the results of a study on the additional doping of silicon solar cells with nickel atoms, for factors affecting the long-wave and short-wave efficiency. Nickel doping has been shown to increase the efficiency of solar cells. It is determined that in the visible region of the spectrum the spectral sensitivity of a silicon solar cell doped with nickel is higher up to 25÷35% due to a decrease in surface recombination. Technological recommendations for nickel doping of single-crystal silicon solar cells are proposed to be combined without significant changes with the standard technological process for manufacturing solar cells.

Molecular designs, synthetic strategies, and properties for porphyrins as sensitizers in dye-sensitized solar cells

Dyes play a crucial role in the cell performance of dye-sensitized solar cells (DSSCs), and versatile synthetic strategies towards well-tailored porphyrins for DSSCs have been developed for achieving high photovoltaic performances.

Copper(ii) and cobalt(iii) Schiff base complexes with hydroxy anchors as sensitizers in dye-sensitized solar cells (DSSCs).

Two Schiff base complexes of copper(ii) and cobalt(iii) having the formulae [CuL2] (Cu-Sal) and [CoL3] (Co-Sal) (HL = 2-(((2-hydroxyethyl)imino)methyl)phenol) have been synthesized and characterized microanalytically, spectroscopically and in the case of Cu-Sal using single crystal X-ray diffraction technique. The single crystal X-ray analysis reveals a square planar geometry around Cu(ii) satisfied by phenoxide oxygen and imine nitrogen of the L- ligand to generate a six membered chelate ring. The solid state structure of Cu-Sal is satisfied by varied intermolecular non-covalent interactions. The nature of these interactions has been addressed with the aid of Hirshfeld surface analysis. Both compounds have been used as sensitizers in TiO2 based dye sensitized solar cells (DSSCs) and the DSSC experiments revealed that Co-Sal offers better photovoltaic performance in comparison to Cu-Sal. The Co-Sal exhibited a J sc of 9.75 mA cm-2 with a V oc of -0.648 V, incident photon to current conversion efficiency (IPCE) of 57% and η of 3.84%. The relatively better photovoltaic performance of Co-Sal could be attributed to better light absorption and dye loading than that of Cu-Sal.

A Study on Morphological Effect of Nano WO3 Particles for Dye Sensitized Solar Cell Application

Tungsten oxide (WO3) nanoparticles of rod-like and spherical morphologies were synthesized using sol-gel modified Pechini’s method. The spherical morphology is achieved by optimizing precursor concentration. The synthesized WO3 nanoparticles were characterized by powder XRD for phase analysis and SEM for size and morphological analysis. It was revealed that the synthesized particles have spherical and rod-like shapes, are in the monoclinic phase and in the nano range. Dye sensitized solar cells were fabricated by incorporating WO3 nanoparticles in 0.5, 1 and 2 wt.% with anatase TiO2 nanoparticles and their photovoltaic characteristics were investigated. It was found that the incorporation of WO3 nanoparticles with nano TiO2 particles considerably enhanced the short circuit current density (Jsc) and power conversion efficiency (η). Further, it was found that WO3 nanoparticles with small size and spherical morphology have higher short circuit current density (13.27 mA cm-2) and power conversion efficiency (6.63%) compared to rod-like WO3 nanoparticles.

Hologram quantitative structure-activity relationship guided in silicon molecular design of phenothiazine dye sensitizers for dye-sensitized solar cells

Hologram quantitative structure–activity relationship (HQSAR) method was successfully introduced into the structure-performance study on the phenothiazine dye sensitizers of dye-sensitized solar cells. A total of 79 phenothiazine derivatives were investigated to build the HQSAR model of power conversion efficiency. The fragment parameters of the established optimal HQSAR model are fragment size: “4 ∼ 7”, hologram length: “353”, and fragment distinction: “bonds, connections, chirality, donor and acceptor atoms”. The predictive performance of the HQSAR model was evaluated with external test set validation and leave-one-out cross-validation. The validation results demonstrate that the developed model possesses high prediction ability and stability. The molecular contribution map of this model was analyzed to reveal the key structures and modification positions for improving the power conversion efficiency, and was used to guide the molecular design of high performance dye sensitizers. The theoretical prediction result of several literature reported phenothiazine compounds indicates that the developed model is an effective and important guidance to the molecular design of dye sensitizers. Therefore, several new phenothiazine derivatives with theoretically improved power conversion efficiency were designed by the proposed HQSAR-based strategy.

D-π-A structured porphyrin sensitizers for dye-sensitized solar cells

Two porphyrin-based D-[Formula: see text]-A structured dyes of SGT-026 and SGT-027 with different acceptor groups were synthesized and characterized for dye-sensitized solar cells. The structure of SGT-027was designed with a very strong acceptor unit of (5-(naphtho[1,2-c:5,6-c[Formula: see text]]bis[1,2,5]-thiadiazolyl)benzoic acid) (NBTD), resulting in more red-shifted absorption bands and broader NIR absorption ability, but SGT-026 porphyrin with a weak acceptor unit of (2-(thieno[3,4-c]pyrrole-4,6(5H)-dionyl)benzoic acid) (TPD) exhibited a blue-shifted Q band absorption, compared to the reference SGT-021dye with a strong acceptor unit of (4-(benzo[c][1,2,5]thiadiazol-4-yl)benzoic acid) (BTD). The photophysical properties of these D-[Formula: see text]-A structured porphyrin sensitizers depend on the degree of the intramolecular charge transfer character with the electron-withdrawing ability order of NBTD> BTD> TPD. The photovoltaic performances were evaluated using cobalt (II/III)-based redox electrolyte, SGT-027 reached a power conversion efficiency (PCE) of up to 7.5%, which was surprisingly inferior to the benchmark porphyrin sensitizer SGT-021 with a PCE of 10.9%, and a PCE of 5.9% was exhibited by SGT-026, under AM 1.5G sunlight. The optical, and electrochemical properties and DFT calculations were utilized to understand the cell performance difference between SGT-dyes.

The Use of Copper-Quercetin Complex as Photosensitizer in Dye Sensitive Solar Cells and Its Photovoltaic Performance

The Use of Copper-Quercetin Complex as Photosensitizer in Dye Sensitive Solar Cells and Its Photovoltaic Performance

Dye Sensitized Solar Cell (DSSC) Fabrication Using Methanol Extract of Onion Peel as a Natural Sensitizer

Methanol extracts of onion peel waste (Allium cepa) were applied as natural sensitizer in Dye-Sensitized Solar Cell (DSSC) fabrication. This research investigated the dye characteristics of onion peel extract and its power conversion efficiency. Onion peel extraction was carried out using unacidified methanol extract (UME) and acidified methanol extract (AME). Dye absorption was characterized by UV-Vis Spectrophotometer at a wavelength of 200-800 nm and FT-IR at a wave number of 4000-500 cm-1. The power conversion efficiency of the fabricated DSSC was determined by calculating the voltage and current generated by the multimeter. The red onion peel extracts, both acidified and unacidified methanol, had maximum absorption at UV-Visible range (457, 659 and 662 nm). Onion peel extract has several functional groups such as –OH, C=O, C-O-C, C=C, and C-H aromatics- showing specific absorption corresponding to the anthocyanin structure. A solar energy conversion efficiency of η= 0.0413% was obtained from UME extract with a short circuit current of up to Jsc=0.6031 mAcm-2 and a fill factor of 0.2764.

New photosensitizers that are based on carbazoles and have thiophene bridges with a low bandgap do 32% better than N719 metal complex dye

Synthesis of metal-free organic sensitizers is a promising route for obtaining low-cost, high-efficiency sensitizers for dye-sensitized solar cells (DSSCs). We present the results of a comprehensive photovoltaic analysis of four carbazole organic sensitizers with a D-A architecture in this study. MES 1-4 have been developed and used as sensitizers in DSSC applications. Using MES1-4 as sensitizers results in a broader light-harvesting ability (400–800 nm) and higher photovoltaic efficiency at a range of 6.06–9.55 %. Herein, the introduction of thiazolidine-4-one ring engineering into MES4 as a rich electron acceptor enhanced electron injection and inhibited electron recombination in thiazolidine-4-one sensitizers. The MES4 system has the highest light harvesting ability and reflectivity owing to the existence of distinct functional groups that enhanced the capacity to bind the dye with the semiconductor layer (TiO2 device's efficiency). In conclusion, the DSSC using the novel electron acceptor thiazolidine-4-one ring sensitizer achieves an unexpected PCE of 9.55 % and a 32 % increase over using the N719 metal complex dye. All sensitizers based on carbazole compounds had good photovoltaic performance.

D-D-π-A-π-A-based quinoxaline dyes incorporating phenothiazine, phenoxazine and carbazole as electron donors: Synthesis, photophysical, electrochemical, and computational investigation

Three novel D-D-π-A-π-A types of metal-free organic dyes, QX-D1, QX-D2, and QX-D3, were designed and synthesized in excellent yields (94–99 %). An auxiliary acceptor of 2,3-diphenylquinoxaline was incorporated between two units of thiophene as π-spacers so that one ring is connected with cyanoacrylic acid as an anchoring electron acceptor, and the other one lies between the quinoxaline moiety and an electron donor to build the π-A-π-A part.The other D-D part of the dye skeleton was made using donors-based phenothiazine (PTZ), phenoxazine (POZ), and carbazole (CZ) containing a tolyl moiety as an auxiliary donor. For this purpose, an efficient multistep synthetic approach for the synthesis of the dyes was investigated. The chemical structures of all compounds were confirmed by spectral data (FTIR, 1H NMR, 13C NMR, and HRMS). The QX-D1, QX-D2, and QX-D3 dyes showed ICT bands in THF solution at 511, 542, and 526 nm, respectively and high molar absorptivity of 23434, 29825, and 23214 M−1 cm−1, respectively. Among the donor, QX-D2-based POZ revealed bathochromic and hyperchromic shifts in the absorption due to the influence of the oxygen atom in POZ compared with the sulfur atom and non in PTZ and CZ, respectively. The cyclic voltammetry data revealed that the HOMO and LUMO energy levels forQX-D1,QX-D2, andQX-D3dyes were found to be (−5.07, −2.86 eV), (−4.90, −2.72 eV), and (−5.13, −3.04 eV), respectively. Furthermore, the density functional theory (DFT) and time-dependent TD-DFT at the B3LYP/6-31G(d) level were investigated to shed light on the bridged effect on geometric and TD-BH and H/6-31G(d) for optoelectronic properties. The binding energies of the complex dye@TiO2 cluster have also been explored. A good agreement between theoretical and experimental data was obtained. Thus, the dyes successfully achieved the desired outcomes, qualifying them for later use in photovoltaic applications such as sensitizers in dye-sensitized solar cells (DSSCs).

Novel tert-butylated spirobifluorene -based organic sensitizers for dye-sensitized solar cells

Six organic sensitizers were synthesized starting from readily available reagent biphenyl. The introduction of tert-butylated spirobifluorene unit as the central building block was targeted for suppressing the dye-aggregation and improving the thermal/photo-stability and solubility. As a result, no obvious aggregations were observed in the absorption spectra of TM2, TM3, TM4 and TM6 sensitized TiO2 films. The higher Jsc,Voc and η (>5%) values of the TM6, TM3 and TM2 sensitized devices as compared with those of the devices based on TM1 and TM5 demonstrated the beneficial influence of weak or no aggregation. High thermal-stability and photo-stability for six dyes have been achieved. The electron lifetimes of TM2 and TM3 are over 122 ms, which are longer than those of many reported dyes. In addition, TM3 showed a very high molar extinction coefficient in visible region (5 × 104 M−1cm−1) due to the increase of the relative number of triphenylamine unit in chromophore.

Comparative study of natural dye-sensitized solar cells using inedible extracts from kumkum, kamala and malabar spinach fruits

In this work, natural dyes were extracted from inedible plant sources, especially seeds of Bixa orellana (kumkum), pericarp of Mallotus phillipensis (kamala) fruits and ripe fruits of Basella alba (malabar spinach) and a detailed comparative study on the efficiency of such extracts or natural compounds as dye sensitizers for solar cell performed. The major constituents or pigments in these extracts are bixin in Bixa orellana, rottlerin in Mallotus phillipensis and betalain/betacyanin in Basella alba fruits. The efficiency of the best performing devices was 0.67% for kumkum, 0.55% for kamala and 0.32% for malabar spinach extracts. Theoretical calculations were also performed to compare the results and it showed congruity with the experimental observations. The thermodynamic parameters such as the electron injection efficiency and the regeneration efficiency were calculated using density function theory (DFT) for the three natural dyes and it was observed that kumkum dye to be the most efficient and malabar spinach to be the least efficient among the three natural dye sensitizers as the same trend with the experimental results. These bio-compatible and inedible extracts are easily available and inexpensive for their use as sensitizers as an alternative to the toxic and expensive synthetic sensitizers.

Optimization of chlorophyll extraction from pineapple plantation waste

The abundance of pineapple waste generated in Malaysia has becomes a serious issue as it puts our environment in grave danger. The presence of chlorophyll in pineapple waste has attracted many researchers to produce a natural dye from chlorophyll as a sensitizer for solar cells. Natural dyes can be considered a promising substitute for synthetic dyes as they are more environmentally friendly and cost less when compared to the synthetic dyes that are currently available on the market. This research aims to optimize the conditions of chlorophyll extraction from pineapple leaves using a mechanical extraction method. A response surface methodology was used to design an experimental design table using a central composite design based on two significant factors. The extraction cycle and the storage time varied between 1 and 5 cycles and 7 and 9 h, respectively, were studied. From the study, the maximum concentration of total chlorophyll (TC) was 693.292 mg/L. The optimum conditions for extraction cycle and storage time were at 3 cycles and 8 h, respectively. Among those two factors, it has been discovered that the storage time has a smaller p-value (p = 0.1106) than the extraction cycle, indicating that this factor was the critical factor affecting the TC concentration. The value of R2 for the analysis was 0.8673, making the analysis a well-fitted model. Thus, it has been established that the models are suitable for optimizing the extraction conditions in order to maximize the concentration of TC using the mechanical method.