Dye-sensitized Solar Cells Devices Research Articles

Performance of TiO2, Cu-TiO2, and N-TiO2 nanoparticles sensitization with natural dyes for dye sensitized solar cells

In this work, the eucalyptus and teak leave extracts are used as natural dyes for dye-sensitized solar cells (DSSCs). The TiO2, copper doped -TiO2 (Cu-TiO2), and nitrogen doped-TiO2 (N-TiO2) nanoparticles were synthesized by using the sol–gel method. The structural, morphological and elemental properties of the prepared samples were tested by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). XRD revealed the anatase-TiO2 phase and calculated crystallite sizes are 10, 11.23, and 13.97 nm, correspondingly. SEM micrograph shows the spherical shaped nanoparticles with less agglomeration and primary elements (Ti, O, Cu, N) confirmed by EDS spectra. Further, the nanoparticles used as a photoanode in DSSC device with natural dyes and studied their performance.

Rheological and structural characterization of 3D-printable polymer electrolyte inks

Direct ink writing (DIW) is an extrusion-based technique that is increasingly used for extrusion of gel and quasi-solid polymer electrolytes for energy-based devices. Due to their high tunability in viscoelastic properties, poly(ethylene oxide) (PEO)-based inks are prime candidates as functional substrate material for optimization-based studies to improve extrudate printability. While optimization of ink printability in conventional 2D printing applications has been previously described, we have yet to observe a report analyzing the relationship between the morphological and rheological properties of direct-ink-writable inks tailored for printed energy devices (e.g., dye-sensitized solar cells (DSSCs)). To address this gap, we have characterized various electrolyte inks' morphological, rheological, and structural properties and studied these relationships to modify the ink's flow characteristics during extrusion and structure after deposition with high specificity. These metrics are used to define the electrolyte ink's printability as a step towards realization of printable electrolyte inks for DSSC devices.

Enhanced catalytic performance of Cu2ZnSnS4/MoS2 nanocomposites based counter electrode for Pt-free dye-sensitized solar cells

Low abundance, high cost and corrosiveness towards the liquid electrolyte is the main limitation of Platinum (Pt) as a counter electrode (CE) in dye-sensitized solar cells (DSSCs) in spite of its excellent electrochemical properties. The present study focuses to enhance the electrochemical properties of CZTS by compositing it with MoS2 towards the replacement of Pt. Pure CZTS, pure MoS2, CZTS/MoS2 nanocomposites are synthesized by hydrothermal method, then characterized and compared to analyze their properties. The outcomes of characterizations techniques from XRD, Raman, XPS, SEM, EDS and TEM confirmed the formation of CZTS/MoS2 nanocomposites. The electrochemical characterizations and Impedance analysis of the pure CZTS, pure MoS2 and CZTS/MoS2 are compared. Results showed enhanced catalytic property and lower charge transfer resistance for the CZTS/MoS2 nanocomposites. Nanocomposite with 8 wt% of MoS2 in CZTS exhibited higher carrier concentration of 6.126 × 1018 cm−3, higher mobility of 5.03 cm2Vs−1 and lower resistivity of 2.62 Ωcm compared to CZTS and other nanocomposites. Electrical conductivity and catalytic activity were improved with increase in the wt% of MoS2 in the Cu2ZnSnS4/MoS2 nanocomposites. DSSC device fabricated by interpolating di-tetrabutylammonium cis-bis(isothiocyanate)bis(2,2″-bipyridyl-4,4′dicarboxylato) ruthenium (II) (N719) dye-loaded titanium dioxide (commercial P25 TiO2 as photoanode) and with CZMo8 (as CE) using iodine/iodide as a liquid electrolyte exhibited the maximum open circuit voltage of 720 mV, a short circuit current of 8.45 mA/cm2, a fill factor of 0.66, and a power conversion efficiency of 4.07%.

Hierarchically ordered macroporous TiO2 architecture via self-assembled strategy for environmental remediation

Hierarchical orderd macroporous TiO2 architecture (HOMTA) was prepared with aid of ethylenediamine (EDA) and investigated the impact of amine molecules on the properties of TiO2 architecture. The different variation of amine molecules (EDA) leads to tunning the morphology under hydrothermal approach which is confirmed by FESEM and TEM analysis. The XRD and Raman studies confirms the crystal structure of anatase and brookite phase of TiO2. The surface of the architecture strongly depended on the concentration of EDA which plays a vital role in surface area which is revealed by Brunauer Emmett-Teller (BET) analysis. The obtained HOMTA was employed as photocatalyst and active photoanode in the dye sensitized solar cells (DSSC). The DSSC device exhibits excellent efficiency (η) of 5.27% for the EDA capped TiO2 (S5) which had high surface area (167.11 m2/g) for better dye loading, whereas the lower concentration of EDA capped TiO2 (S1, S2, S3 and S4) resulted the efficiency of 2.14, 3.90, 3.25 and 4.37%, respectively. The efficiency of photocatlysis degradation of the prepared samples (S1, S2, S3, S4 and S5) was 94.8, 90.47, 91.41, 91.32 and 93.75% under light source. The excellent photocatalysis property was achieved by S5 within 6 min due to high surface area which inducing more active site.

Fabrication of Dye-Sensitized Solar Cells (DSSC) Using Mg-Doped ZnO as Photoanode and Extract of Rose Myrtle (Rhodomyrtus tomentosa) as Natural Dye

A dye-sensitized solar cell (DSSC) device using Mg-doped Zn thin films as photoanode and fruit extract of rose myrtle (Rhodomyrtus tomentosa) as the natural dye was investigated. The effect of annealing temperature (400-550°C) on the films of photoanode was systematically studied using an X-ray diffractometer (XRD), UV-Visible Near Infrared (UV-Vis NIR) Spectrophotometer, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). XRD confirm that all sample has the wurtzite hexagonal with crystallite size of 25 nm. The SEM images reveal particles on the surface of the Mg-doped ZnO thin film of irregular shapes. Increasing the annealing temperature leads to a larger particle size and slightly increases bandgap energy. The dye sensitizer of extracted rose myrtle (Rhodomyrtus tomentosa) has a strong absorption at the visible light region. The maximum efficiency of the DSSC device is 3.53% with Mg-ZnO photoanode annealed at 500°C.

Silver Nanowires Modified Flexible Dye-Sensitive Solar Cells and Application With the Internet of Things Under Low Illumination

Silver nanowires (AgNWs) possess excellent mechanical strength, electrical conductivity, and superior flexibility, thus making them exceptional candidates for dopant nanometal. A photoanode modified with AgNWs-titanium dioxide (TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) composite film was prepared and used in flexible dye-sensitized solar cells (DSSCs). The AgNWs were synthesized by a stable polyol method. We employed the field-emission scanning electron microscope and an X-ray diffractometer to characterize the AgNWs. The measurement of the photovoltaic parameters of flexible DSSCs in the basic environment was conducted (air mass (AM) 1.5, 100 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ). Compared with the flexible DSSC based on pure TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , the flexible DSSCs based on AgNWs-TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> had a higher short-circuit current density and photovoltaic conversion efficiency, and the efficiency was increased by 37.40%. The impedance among the photoanode, dye, and electrolyte interface was identified by the electrochemical impedance spectroscopy. We also employed filters to better investigate the photovoltaic conversion efficiency at low incident light intensity. Furthermore, the flexible DSSCs devices were interfaced with an IoT system for the measurement of the stability of flexible DSSCs under long-term use to occur. We measured the flexible DSSCs continuously for 30 days. The photovoltaic conversion efficiency was lost only 10% in 20 days. This suggests that the flexible DSSCs have good mechanical stability, and the adhesion between the AgNWs-TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> photoanodes and the flexible substrate.

Performance improvement of dye-sensitized solar cells by using TiO2 compact layer and silver nanowire scattering layer

In this study, indium tin oxide (ITO) glass was coated with silver nanowires (AgNWs) by ultrasonic spray coating to roughen the ITO surface, yielding a surface texture comparable to that obtained by chemical etching. A compact layer (CL) of titanium dioxide (TiO2) was coated on the AgNWs/ITO surface by sputtering to improve the properties of dye-sensitized solar cell (DSSC). A TiO2 CL was used as a protective layer on AgNWs to prevent oxidation and increase the adhesion of AgNWs. The TiO2 CL also effectively inhibited the carrier recombination between the electrolyte solution and ITO interface, thereby improving the photoelectric conversion efficiency (η) of the DSSC device. The experiment results indicated that the η of DSSC devices with a CL deposited under the working electrode increased from 4.06% to 4.37%. The integration of the CL and AgNWs to CL/AgNWs/ITO structure increased the η of DSSC devices further to 4.59%. Electrochemical impedance spectroscopy was performed to analyze two DSSC structures, namely CL/ITO and CL/AgNWs/ITO; the electron lifetime increased from 0.35 ms to 0.55 ms and the charge collection rate increased from 64.5% to 75.2%. Therefore, CL/AgNWs/ITO working electrode structure can effectively improve the performance of DSSC devices.

Efficiency Boost in Dye-Sensitized Solar Cells by Post- Annealing UV-Ozone Treatment of TiO2 Mesoporous Layer.

The organic residues on titanium(IV) oxide may be a significant factor that decreases the efficiency of dye-sensitized solar cells (DSSC). Here, we suggest the UV-ozone cleaning process to remove impurities from the surface of TiO2 nanoparticles before dye-sensitizing. Data obtained from scanning electron microscopy, Kelvin probe, Fourier-transform infrared spectroscopy, and Raman spectroscopy showed that the amounts of organic contamination were successfully reduced. Additionally, the UV-VIS spectrophotometry, spectrofluorometry, and secondary ion mass spectrometry proved that after ozonization, the dyeing process was relevantly enhanced. Due to the removal of organics, the power conversion efficiency (PCE) of the prepared DSSC devices was boosted from 4.59% to 5.89%, which was mostly caused by the increment of short circuit current (Jsc) and slight improvement of the open circuit voltage (Voc).

Starburst-Shaped D-π-A Chromophores Possessing a Hexaethynylbenzene Core for Dye-Sensitized Solar Cells.

Two starburst-shaped organic chromophores, incorporating a hexaethynylbenzene core modified by five donor branches (D-branches) of (p-dioctylaminostyryl)benzene and one acceptor/anchoring branch (A-branch) of either carboxylic acid-terminated phenylethynylbenzene (SB-07) or cyanoacrylic acid-terminated diketopyrrolopyrrole (DPP)-thiophene (SB-08), were synthesized and applied to dye-sensitized solar cells (DSSCs). In these chromophores, the common donor moiety, five (p-dioctylaminostyryl)phenyl groups, exhibits excellent optical absorption in the visible region (molar absorption coefficient ε > 105 M-1 cm-1 below 500 nm). The A-branch of SB-07 does not possess strong electron-accepting properties; however, the A-branch of SB-08, the DPP-thiophene moiety, serves as a strong electron acceptor site. Furthermore, the intramolecular charge-transfer (ICT) transition between the thiophene and DPP moieties extends the optical absorption range to the near-infrared region (∼800 nm). Optimized DSSC devices using SB-08 with coadsorption of chenodeoxycholic acid, in conjunction with iodide/triiodide-based electrolytes, exhibited incident photon-to-current conversion efficiency (IPCE) exceeding 70% in the 370-700 nm range and over 20% even at 800 nm, with a short-circuit photocurrent density (Jsc) of 19.3 mA cm-2 and a power conversion efficiency (PCE) of 6.4% under AM 1.5G illumination (100 mW cm-2). These results are considerably better than those of SB-07 (Jsc = 7.0 mA cm-2, PCE = 3.3%). The starburst-shaped architecture presented here can be used as a novel structural motif for metal-free organic sensitizers because it enables flexible modification of the multiple D-branches that enhance light-harvesting ability and the A-branch that serves as an excited electron transport pathway.

Quinoline‐Coupled Coumarin‐Based Ruthenium(II) Dye Sensitizer for Photoelectrochemical Cells and Solar Cells: A Mimic for an Artificial‐Light‐Harvesting System

The conversion of solar energy into chemical energy by the use of dye‐sensitized solar cells (DSSCs) and dye‐sensitized photoelectrochemical cells (DSPECs) has been considered a convenient method in recent years. Herein, DSPEC and DSSC devices are fabricated by mimicking the function of photosystem II in natural photosynthesis with a new quinoline‐coupled coumarin‐based ruthenium(II) dye (RQC)‐sensitized TiO2 semiconductor as the light‐harvesting center. By using the RQC‐sensitized TiO2 as the working electrode, photoelectrochemical water‐splitting reactions are effectively conducted in a phosphate buffer solution (pH = 6), with 30 mm triethanolamine as the sacrificial electron donor. Oxygen and hydrogen bubbles are evolved from the working electrode and counter electrode, respectively. By applying +0.78 V potential versus a relative hydrogen electrode, an initial photocurrent density of 11.07 mA cm−2 and a final photocurrent density of 9.66 mA cm−2 are achieved. Under this condition, a maximum photoelectrochemical water splitting efficiency of 4.98% is obtained. The photocurrent–voltage (J–V) characterization of the DSSC device fabricated with RQC under standard AM 1.5G illumination furnishes a Jsc of 11.4 mA cm−2, Voc of 0.69 V, fill factor of 0.53, and power conversion efficiency (η) of 4.16%.

Charge transfer uplift in dye-sensitized solar cells using fibrous nanocrystals of platinum-based bimetallic counter electrodes

Charge transfer dynamic on the surface of a counter electrode (CE) of dye-sensitized solar cells (DSSC) during a photoactivation process relates to the physicochemical properties of the CE. In this paper, we investigated how the co-metal element in the Pt-based bimetallic fibrous nanocrystals (FNC) CE influences the charge transfer dynamic of the dye-sensitized solar cell (DSSC) devices. We discovered that the interfacial charge transfer resistance decreases dramatically in bimetallic CEs if compared with the pristine Pt. For example, it decreases more than 5 times in the AuPt FNC and more than 4 times lower in the AgPt and PdPt FNC CEs. This phenomenon then induced an enhanced carrier diffusion in the device that is reflected by the decrease in the carrier diffusion resistance and the improvement of the carrier lifetime in the device using bimetallic CEs. The DSSCs using the champion CEs, that is AuPt, can produce a short circuit current (Jsc), open-circuit voltage (Voc), and fill factor (FF) as high as 10.63 mAcm−2, 1.00 V, and 0.43, respectively, which correspond to a power conversion efficiency (PCE) of 4.60%. This PCE is approximately 3.5 times higher if compared with the DSSC using the pristine Pt CE. The enhancement of the surface physicochemical properties of the CE due to the bimetallization process is assumed as the key factor for the performance enhancement, the facts that are verified by the X-ray photoelectron spectroscopy and the electrochemical properties analysis results. The synthesis and the device characterization are discussed in detail.

Iron Redox Shuttles with Wide Optical Gap Dyes for High-Voltage Dye-Sensitized Solar Cells.

A series of iron polypyridyl redox shuttles were synthesized in the 2+ and 3+ oxidation states and paired with a series of wide optical gap organic dyes with weak aryl ether electron-donating groups. High voltage dye-sensitized solar cell (HV-DSC) devices were obtained through controlling the redox shuttle energetics and dye donor structure. The use of aryl ether donor groups, in place of commonly used aryl amines, allowed for the lowering of the dye ground-state oxidation potential which enabled challenging to oxidize redox shuttles based on Fe2+ polypyridyl structures to be used in functional devices. By carefully designing a dye series that varies the number of alkyl chains for TiO2 surface protection, the recombination of electrons in TiO2 to the oxidized redox shuttle could be controlled, leading to HV-DSC devices of up to 1.4 V.

Effect of low grain boundary crystallization Cu2ZnSnSxSe4−x counter electrode on the performance of dye-sensitized solar cells

The high surface area of porous Cu2ZnSnSxSe4−x (CZTSSe) counter electrodes (CEs) was commonly used for dye-sensitized solar cells (DSCs), because it can retard electron transport processes and form high quality crystallized film. Herein, we introduced a facile method to prepare CZTSSe film with bulk large-grained crystal by vacuum fast processing (VFP), which beneficial to form oriented crystalline film and reduce grain the film boundaries. Thus, performances of the DSCs devices showed an outstanding PCE of 8.3% with Voc, Jsc and fill factor of 0.729 V, 16.9 mA·cm−2, and 67.4%, respectively. With conducting spectral characterization and electrochemical techniques, it was found that the accelerating charge transfer speed and superior electrocatalytic activities contribute the majority part to DSCs photovoltaic performances. Furthermore, under AM1.5 illumination at 45 °C, the DSCs devices showed good stability and retained over 94% of its initial performance for 1000 h light soaking, indicating of their general applicability in fabricating high-performance DSCs.

Theoretical investigation of the nitrogen-heterocyclic as π-linker in diphenylthienylamine-based dyes adsorbed on TiO2 nanotubes for DSSCs applications

A planer π-conjugated spacer is one of the strategies used to develop the performance of the dye-sensitized solar cell (DSSC). This study focuses on describing the effect of the nitrogen-based heterocycles as π-linker on the properties of novel photosensitizers based on diphenylthienylamine (DPTA). The π-linker is five- (5M), or six-membered rings (6M) contains none (D0), one (D1), two (D2), and three (D3) nitrogen atoms. The geometrical structures, electronic properties, and photovoltaic parameters are calculated using the DFT/B3LYP and TD-DFT/CAM-B3LYP functional with 6-31G+(d,p) basis set. As well, the polarised continuum model (PCM) is used to simulate the solvation effects. To understand the mechanism of electrons injection to semiconductor, the adsorbed dyes on titanium dioxide nanotube (TiO2NT) are studied, using B3LYP/6-31G(d) and LANL2DZ basis sets. The results revealed that 6M is better than 5M dyes due to the extended conjugation in the 6M dyes. As well, the 5M-D0 (cyclopenta-1,3-diene) shows a broad absorption band from 400 to 850 nm at the near-infrared (NIR) region with an absorption wavelength of 561.24 nm. Besides, 5M-D0, 6M-D3 (1,2,4-triazine) can be considered promising photosensitizers due to their unique electronic properties that will be expected to improve the power conversion efficiency of the DSSC device.

Liquid phase deposition/anodizing of TiO2 nanotube working electrode for dye-sensitized solar cells

With a high carrier transfer rate, anodizing TiO2 nanotubes (TNTs) are often used as the working electrode in dye-sensitized solar cells (DSSCs). However, the TNT length is restricted by the thickness of the Ti foil, which in turn limits the dye adsorption efficiency of the working electrode. To combat this problem, this study used liquid-phase deposition (LPD) to fabricate a TiO2 film on anodizing TNT. LPD allows for more rapid and even deposition of TiO2 films on the anodizing TNT structure than does vacuum deposition. Analysis revealed that LPD-TiO2 films fabricated at 3.33 nm/s increased the length of the TNT from 17.76 to 24.80 μm, and the dye adsorption capacity rose from 9.8 × 10−7 to 1.07 × 10−6 mol/m3. Testing confirmed that the photoelectric conversion efficiency of the DSSC device of the LPD/anodizing TNT increased from 2.43% to 2.85%, that the interface impedance of the DSSC device (R2) decreased from 132 to 41.5 Ω, and that the electron lifetime (τe) increased. In sum, the LPD-TiO2 film increased the thickness, dye adsorption efficiency and reduced the oxygen vacancies in the anodizing TNT; in other words, the coating effectively enhanced the photoelectric conversion properties of the DSSC device of the working electrode.

Towards achieving improved efficiency using newly designed dye-sensitized solar cell devices engineered with dye-anchored counter electrodes

Partial absorption of the solar spectrum is one of the key limitations of dye-sensitized solar cells (DSSCs). In an attempt to address this issue, we have developed co-sensitized working electrode based dye anchored counter electrode (DACE) DSSC strategy to achieve panchromatic absorption using multiple dyes. Herein, we have synthesized a dithionopyrrole based TP–DTP dye and a porphyrin-based Y351-S dye and explored to a new type of DSSCs modified with DACE. To realize the effect of DACE electrode on the DSSC efficiency, we have fabricated five different DSSCs devices namely, S-DSSC1, S-DSSC2, S-DACE, CO-DSSC, and CO-DACE using these synthesized dyes and compared their performances systematically. In addition, the detailed impedance and stepped light-induced transient measurements of the photocurrent and voltage (SLIM-PCV) experiments are also performed to assess the charge transfer resistance and charge collection efficiency of these devices. The highest efficiency of 8.72±0.15% is observed for the CO-DACE-based devices, which is higher than the traditional DSSCs made of single dye-sensitized (S-DSSC1 and S-DSSC2), and co-sensitized DSSC (CO-DSSC). It can be attributed to the enhanced incident photon to current conversion efficiency (IPCE) and short circuit current (Jsc) which clearly portray the advantage of DACE electrode in harvesting maximum incident light.

Prediction of Power Conversion Efficiencies of Diphenylthienylamine-Based Dyes Adsorbed on the Titanium Dioxide Nanotube.

The power conversion efficiency (η) is the most important key to determine the efficiency of dye-sensitized solar cell (DSSC) devices. However, the calculation of η theoretically is a challenging issue since it depends on a large number of experimental and theoretical parameters with extensive related data. In this work, η was successfully predicted using the improved normal model with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) for eight diphenylthienylamine-based (DP-based) dyes with various π-bridge adsorbed on titanium dioxide. The titanium dioxide is represented by a nanotube surface (TiO2NT); this surface is rarely investigated in the literature. The π-linker consists of five (DP1)- or six (DP2)-membered rings and contains none to three nitrogen atoms (D0–D3). The reliability of the estimated values was confirmed by the excellent agreement with those available for the two experimentally tested ones (DP2-D0 and DP2-D2). The deviations between the experimental and estimated values were in the ranges of 0.03 to 0.06 mA cm–2, 0.05 to 0.3 mV, and 0.37 to 0.18% for short-circuits current density (Jsc), open-circuit voltage (Voc), power conversion efficiency (%η), respectively. More importantly, the results revealed that using pyridine (DP2-D1), pyrimidine (DP2-D2), and 1,2,4-triazine (DP2-D3) improves the power conversion efficiencies in the range of 6.03 to 6.90%. However, the cyclopenta-1,3-diene (DP1-D0) shows superior performance with a predicted η value that reaches 9.55%.

Directly grown of NiCo2S4 nanoparticles on a conducting substrate towards the high-performance counter electrode in dye-sensitized solar cell: A combined theoretical and experimental study

Development of alternate counter electrode for the dye-sensitized solar cell (DSSC) using simple and single method are the major focus of the research to resolve problems related to the platinum (Pt)-based counter electrode. In the present work, NiCo2S4 based counter electrode has been directly developed on the fluorine-doped tin oxide coated glass substrate (FTO) using one step and simple hydrothermal method. The prepared NiCo2S4@FTO electrode was characterized by the range of spectroscopic and microscopic techniques as well as further assembled in the DSSC device in order to evaluate the electrode performance. The NiCo2S4 counter electrode exhibited the 6.53% photovoltaic performance in the assembled DSSC which is almost similar to the benchmark Pt based counter electrode (6.88%) under similar experimental conditions. The excellent performance of the elected NiCo2S4@FTO electrode could be due to the high electrocatalytic activity towards the reduction of the I3− to I− and smaller size of the nanoparticle which provide high surface area and catalytic sites. We adapted a theoretical model based on electrical considerations to study the impact of physical parameter of DSSC cell on the – characteristic, performance and photovoltaic efficiency, using the experimental parameters. The model is reproducing perfectly the I–V curve and related DSSC characteristics.

Dye sensitized solar cells fabricated based on nanocomposite photoanodes of TiO2 and AlMo0.5O3 perovskite nanoparticles

To enhance the photovoltaic efficiency of dye sensitized solar cells (DSSCs), tri-layered photoanodes composed of compact, mesoporous and light scattering TiO2 layers were fabricated. Moreover, inorganic AlMo0.5O3 perovskite nanomaterial was synthesized using sol gel method and different AlMo0.5O3/TiO2 nanocomposites were achieved by adding various amounts (0–3.0%) of the AlMo0.5O3 nanoparticles to the mesoporous TiO2 layer in the photoanode. All of the nanocomposite photoanodes and the AlMo0.5O3 nanostructure were characterized by XRD, SEM, EDS, DRS, photoluminescence (PL) and FT-IR analysis techniques. Also, the effect of AlMo0.5O3 nanoparticles on the power conversion efficiency (PCE) of the DSSC devices was examined. The measured optical band gaps of all nanocomposite photoanodes were calculated in the range of 2.68–3.10 eV. The photovoltaic parameters extracted from the J-V plots of the DSSCs illustrated that the champion cell fabricated using mesoporous TiO2 + 0.5%AlMo0.5O3 nanocomposite photoanode had PCE = 5.30% with JSC = 10.96 mA.cm−2, VOC = 0.76 V and FF = 0.64. This result revealed that the TiO2 + 0.5%AlMo0.5O3 composite increased the device efficiency by 2.79 times as compared to the DSSC fabricated using bare TiO2 (champion PCE = 1.90% with JSC = 7.90 mA.cm−2, VOC = 0.67 V and FF = 0.36). Comparing the JSC and VOC values of the champion device with those of the DSSC with bare TiO2 photoanode confirmed that incorporation of the AlMo0.5O3 in TiO2 layer highly improved the charge transfer in the device and simultaneously declined the recombination of charge carriers. Hence, the perovskite AlMo0.5O3 could be suggested as an efficient nanomaterial for application in DSSCs.

A novel porphyrin dye with phenoxazine as donor unit for efficient dye-sensitized solar cells

A novel porphyrin dye T-2 with phenoxazine (POZ) as donor unit has been synthesized and utilized for dye-sensitized solar cells (DSSC). Compare with porphyrin dye T-1 (in which triphenylamine as a donor unit), the DSSC based on T-2 exhibited a significantly higher Jsc (16.35 mA cm−2) and Voc (670 mV) than that of T-1 (9.13 mA cm−2, 610 mV), which attribute to the higher IPCE and τ of the device based on T-2. Correspondingly, the T-2-based device achieved a photoelectric conversion efficiency (PCE) of 7.64% (N719, 8.45%). By detailed investigation of the relationship between structure and performance, we found the butterfly-shaped structure, stronger electron-donating capability, and the extra alkyl chain of POZ are the main reasons leading to better performance of T-2 than that of T-1 in the DSSC device.