The Effect of Fullerene Derivatives Ratio on P3HT-based Organic Solar Cells

The effect of fullerene ratio PCBM and ICBA on the P3HT-based solar cells were investigated under ambient conditions; the ratio was varied in the range of 1-3. The optical, morphological, structural, and electrical characteristics were investigated both in dark and under illumination. The absorption spectra have revealed a decrease in the intensities by increasing the fullerene ratio and the peaks were blue shifted. Moreover, florescence spectra demonstrated charge transfer from P3HT to fullerene molecules due to uniform distribution of fullerene domains within the P3HT matrix. XRD patterns have shown a strong reduction in the crystallinity by increasing the ratio of fullerene within the blend. Furthermore, AFM images showed smother surface corresponding to pinholes with higher ratio while rougher surface with lower fullerene ratio was observed. The best performance was recorded for P3HT:PCBM (3:1) with VOC = 0.58 volt, JSC = 9.9 mA.cm-2 and PCE 1.82%. The fill factor (FF) was found to be small for all studied samples which could be associated with the preparation conditions where all samples were prepared under normal ambient. Devices which demonstrated best performance were attributed to improved crystallinity and enhanced light absorption of the active layer

Metal salt modified PEDOT : PSS as anode buffer layer and its effect on power conversion efficiency of organic solar cells

The effects of metal chlorides such as LiCl, NaCl, CdCl2 and CuCl2 on optical transmittance, electrical conductivity as well as morphology of PEDOT:PSS films have been investigated. Transmittance spectra of spun PEDOT:PSS layers were improved by more than 6 to a maximum of 94 in LiCl doped PEDOT:PSS film. The surface of the PEDOT:PSS films has exhibited higher roughness associated with an increase in the electrical conductivity after doping with metal salts. The improvement in the physical properties of PEDOT:PSS as the hole transport layer proved to be key factors towards enhancing the P3HT:PCBM bulk heterojunction (BHJ) solar cells. These improvements include significantly improved power conversion efficiency with values as high as 6.82 associated with high fill factor (61) and larger short circuit current density (�18 mA cm-2). Keywords: Chlorine compounds; Conversion efficiency; Electric conductivity; Electrodes; Heterojunctions; Metals; Semiconductor doping; Solar cells, Electrode modification; Metal salt; Organic solar cell; P3HT:PCBM; PEDOT:PSS, Conducting polymer

P3HT:PCBM-based organic solar cells : Optimisation of active layer nanostructure and interface properties.

Organic solar cells (OSCs) have attracted a significant attention during the last decade due to their simple processability on a flexible substrate as well as scope for large-scale production using role to role technique. Improving the performance of the organic solar cells and their lifetime stability are one of the main challenges faced by researchers in this field. In this thesis, work has been carried out using a blend of Poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-Phenyl C[61] butyric acid methyl ester (PCBM) as an active layer in the ratio of (1:1) (P3HT:PCBM). The efficiency and stability of P3HT:PCBM-based solar cells have been examined using different methods and employing novel materials such as1-[N-(2-ethoxyethyl) pent-4-ynamide] -8 (11), 15 (18), 22 (25) -tris-{2-[2-(2-ethoxyethoxy) ethoxy]-1-[2-((2- ethoxyethoxy) - ethoxy) methyl] ethyloxy} phthalocyaninato zinc (II) (ZnPc) to construct a ternary hybrid as the active layer. Controlling the morphology and crystallinity of P3HT:PCBM active layer was carried out using different solvents including chloroform (CF), chlorobenzene (CB) and dichlorobenzene (DCB) and their co-solvents in the ratio of (1:1) to dissolve the P3HT:PCBM blend. Optimum morphology and crystallinity were achieved using a co-solvent made of CB:CF with the obtained solar cell exhibiting the highest performance with PCE reaching 2.73% among other devices prepared using different solvents. Further device performance improvement was observed through optimization of active layer thickness with studied thickness falling in range 65-266 nm. Measurements of the PV characteristics of the investigated OSC devices have revealed optimum performance when active layer thickness was 95 nm with PCE=3.846%. The stability of the P3HT:PCBM-based devices on optimisation of the active layer thickness has shown a decrease in PCE of about 71% over a period of 41 days. Furthermore, P3HT has been blended with different fullerene derivatives (PC[60]BM, PC[61]BM, PC[70]BM and PC[71]BM) and the active layers were processed using the optimum solvent as well as optimum film's thickness.These PCBM derivatives have different lower unoccupied molecular level (LUMO) and different higher occupied molecular level (HOMO) positions, which subsequently influence the PV parameters of the OSCs such as the device open circuit voltage (V[oc]) and its built-in potential (V[bi]). P3HT:PC61BM-based blend has exhibited the highest device performance with PCE reaching 4.2%. Using the above mentioned optimum parameters, the P3HT:PCBM-based devices have been subjected to post-deposition annealing at different temperatures in the range 100-180°C. Efficient device performance was ascribed to P3HT:PCBM layers being subjected to post-deposition heat treatment at 140°C with PCE=5.5%. Device stability as a result of post-deposition heat treatment has also been shown to improve with PCE degrading by about 38% after 55 days.The use of interfacial layer is found to play a key part in modifying the solar cell performance; using electron transport layer (ETL) such as aluminium tris(8-hydroxyquinoline) (Alq3) as a solution processable layer has contributed in increasing PCE to 4.25%, while, using PEDOT:PSS as a hole transport layer (HTL) doped with metal salts has significantly contributed in increasing PCE to reach 6.82% in device when PEDOT:PSS was doped with LiCl aqueous solution. Stability study for the device based on HTL has shown degradation in the PCE from 6.82% to around 1% over 96 days. Using ETL and HTL simultaneously in a complete device has shown a further enhanced PCE reaching 7%. In a further study, doping the P3HT:PCBM with the novel ZnPc hybrids (SWCNTs and reduced graphene oxide (rGO) are covalently and non-covalently functionalised to ZnPc) with the weight ratio of (1:0.01) has significantly altered the solar cell device properties. The best performance is based on P3HT:PCBM blended with ZnPc-SWCNTs-co bonded as a ternary active layer demonstrating device PCE of 5.3% compared to a reference device based on bare P3HT:PCBM blend with PCE of 3.46%

Rutile TiO2 films as electron transport layer in inverted organic solar cell

Titanium dioxide (TiO2) thin films were prepared by sol–gel spin coating method and deposited on ITO-coated glass substrates. The effects of different heat treatment annealing temperatures on the phase composition of TiO2 films and its effect on the optical band gap, morphological, structural as well as using these layers in P3HT:PCBM-based organic solar cell were examined. The results show the presence of rutile phases in the TiO2 films which were heat-treated for 2 h at different temperatures (200, 300, 400, 500 and 600 °C). The optical properties of the TiO2 films have altered by temperature with a slight decrease in the transmittance intensity in the visible region with increasing the temperature. The optical band gap values were found to be in the range of 3.28–3.59 eV for the forbidden direct electronic transition and 3.40–3.79 eV for the allowed direct transition. TiO2 layers were used as electron transport layer in inverted organic solar cells and resulted in a power conversion efficiency of 1.59% with short circuit current density of 6.64 mA cm−2 for TiO2 layer heat-treated at 600 °C

Study the Rheological and Mechanical Properties of PVA/CuCl2 by Ultrasonic

Some of physical properties of polyvinyl alcohol dissolves in distilled water had been studied before and after adding different weights of copper (II) chloride (CuCl2), the Rheological properties shows that the densities variation are intangible and shear viscosity are responsible for reducing velocity, bulk modulus and transmittance the absorption coefficient of ultrasonic waves and relaxation amplitude are increasing with adding copper (II) chloride because there will be more molecules in solution and this lead to more attenuation against wave propagation. Keywords: PVA solution, mechanical properties, rheological properties, ultrasound technique

Study the Rheological and Mechanical Properties of PVA/NH4Cl by Ultrasonic

Some of physical properties of polyvinyl alcohol dissolves in distilled water had been studied at different concentration (0.25%, 0.5%, 0.75%, 1.0%, and 1.25%) before and after adding 1gm from NH4Cl for all concentrations, the Rheological properties such as shear viscosity, relative viscosity and reduced viscosity are measured and after that the ultrasonic velocity had been measured by ultrasonic waves system at frequency 40 KHz, other mechanical properties had been calculated such as absorption coefficient of ultrasonic waves, relaxation time, relaxation amplitude, specific acoustic impedance, compressibility and bulk modules. Another acoustic mechanical properties were measured and calculated at a same time such as the ultrasonic wave amplitude before and after absorption by solution were showed on oscilloscope ,then we calculated absorption coefficient. The results show that all these properties are increasing with the increase of the polymer concentration except velocity is decreasing with increase the concentration; results also show that when adding NH4Cl these properties are increasing. Keywords: PVA solution, mechanical properties, rheological properties, ultrasound technique

Enhancement Mechanical Properties of Barium Chloride by Adding Copper Chloride using Ultrasonic Technique

Some of physical properties of BaCl2 dissolves in distilled water had been studied at different concentrations (0.05%, 0.1%, 0.15%, 0.2%, 0.25% and 0.3%) (gm./ml) before and after adding (0.3)gm of CuCl2 for all concentrations , the mechanical properties such as ultrasonic velocity had been measured by ultrasonic waves system at frequency 25 KHz, other mechanical properties had been calculated such as absorption coefficient of ultrasonic waves, relaxation time, relaxation amplitude, specific acoustic impedance, compressibility and bulk modules. The results show that all these properties are increasing with the increase of the polymer concentration except compressibility is decreasing with the increase of the concentration; results show that when adding CuCl2  these properties are increasing except compressibility is decreasing. Results also shows that adding CuCl2 to BaCl2 enhances the ultrasonic absorption coefficient as a result of high values after addition. Keywords: BaCl2 solution, CuCl2 solution, mechanical properties, ultrasound technique.

The effects of solvent treated PEDOT:PSS buffer layer in organic solar cells

Various treatments on the PEDOT:PSS films were carried out to investigate it’s influence on the conductivity, morphology, transmittance and the corresponding impact of the performance of the organic photovoltaic devices based on the PCPDTBT:PCBM and P3HT:PCBM blends. These processing including doping PEDOT:PSS with DMF and ME solvents and exposing these films to the vapor of DMF and ME solvents, separately. A considerable enhancement of the conductivity and transmittance of PEDOT:PSS was observed after doping solvent into the PEDOT;PSS solution followed by solvent treatment through exposing these films to solvents environment. The best organic PV doped devices based on either PCPDTBT:PCBM or based on P3HT:PCBM with power conversion efficiency were 2.93% compared to 1.87% for the pristine PV devices or 2.79% compared to 1.77% for the pristine devices, respectively. The conductivity improvement was highly influenced by solvent treatment

Synthesis, Characterization and Gas Sensor Application of New Composite Based on MWCNTs:CoPc:Metal Oxide

تم تخليق فثالوسيانين الكوبالت الجديد المعوض (CoPc) باستخدام مواد البدء النفثالين -1،4،5 ، ثنائي هيدريد حامض التراكربونيك (NDI) عن طريق العملية الجافة. تم تصنيع الأوكسيدات المعدنية (60٪ Ni3O440٪ -Co3O4) مع الأنابيب النانوية الكاربونية متعددة الحوائط (F-MWCNTs) لإنتاج المتراكب النانوي (F-MWCNTs / MO)  (E2) وخلطها مع CoPc لإنتاج (F-MWCNT) / CoPc / MO) (E3). تم فحص هذه المركبات باستخدام طرق تحليلية وطيفية مختلفة مثل H-NMR1  ، مطياف FTIR ، حيود الأشعة السينية (PXRD)  (2θ o = 10-80) ، مطيافية رامان ، وقياس الطيف المرئي للأشعة فوق البنفسجية. ثم تم فحص نشاط هذه المواد لاستشعار غازات (NH3 ، ميثانول ، أسيتون).كان تركيز المحاليل المستخدمة 0.2 ملغم من المادة المحضرة  لكل1 مل من الامونيا, الميثانول والاسيتون. تم أجراء القياسات بدرجة حرارة 298 كلفن.  كانت الأشكال السطحية للمواد المحضرة غير متجانسة.The synthesis of new substituted cobalt Phthalocyanine (CoPc) was carried out using starting materials Naphthalene-1,4,5, tetracarbonic acid dianhydride (NDI) employing dry process method. Metal oxides (MO) alloy of (60%Ni3O4 40%-Co3O4 ) have been functionalized with multiwall carbon nanotubes (F-MWCNTs) to produce (F-MWCNTs/MO) nanocomposite (E2) and mixed with  CoPc to yield (F-MWCNT/CoPc/MO) (E3). These composites were investigated using different analytical and spectrophotometric methods such as 1H-NMR (0-18 ppm), FTIR spectroscopy in the range of (400-4000cm-1), powder X-rays diffraction (PXRD, 2θ o = 10-80), Raman spectroscopy (0-4000 cm-1), and UV-Visible spectrophotometry (0-800 nm). Then the activity of these materials was investigated as a gas sensing of (Ammonia, Methanol and Acetone). For each case, 0.2 mg/.mL of the prepared Copc, Copc/MWCNT, Copc/MWCNTs–MO was dispersed in 1m of ammonia, methanol and acetone at 298K. The surface morphology of the prepared materials was heterogeneous

Preparation and study the mechanical properties of CMC/PVA composites by sound waves

The CMC/PVA composite membranes were prepared by casting method, the appropriate weight of CMC was variable (0.1, 0.15, 0.2, 0.25 and 0.3 gm) was dissolved in (25ml) of distilled water under stirring and heat (80?C) for (30 min.) then add the PVA with different weights (0.2, 0.4 and 0.6 gm) for each CMC weight. In order to evaluate the mechanical properties of CMC/PVA composite the ultrasonic measurements were performed at the samples , these properties are ultrasonic velocity, compressibility, acoustic impedance and bulk modulus, were made at fixed frequency (f =2.5 KHz), another acoustic mechanical properties were measured and calculated at a same time such as the ultrasonic wave amplitude before and after absorption by composite were measured using oscilloscope ,then we calculated absorption coefficient , transmittance and the reflected pressure ratio of the sound. It was found that there is significant relationship between ultrasonic velocity and material properties also results show that adding PVA affects on the density then the absorption of the ultrasonic waves inside the composites samples. Keywords: Carboxy methylcellulose; polyvinyle alcohol; mechanical properties; casting method