Annisa Aprilia

Charge Carrier Dynamics of Active Material Solar Cell P3HT:ZnO Nanoparticles Studied by Muon Spin Relaxation (μSR)

Poly (3-hexylthiohene) (P3HT) has attracted much attention due to their chemical and thermal stability as well as their potential to be used as an active material in solar cells. Recently, hybrid solar cell has been developed due to the combining advantages of organic material (P3HT) and inorganic material such as nanoparticle zinc oxide (ZnO). ZnO is an inorganic material with high electron mobility and easy to prepare as electron acceptor to dissociate excitons formed in conjugated polymer as the active material of solar cells. ZnO also can be prepared as a nanoparticle that can resolve a problem of small exciton diffusion length of P3HT. However, the clearly explanation about the effect of ZnO to the charge carrier dynamics in P3HT is not fully understanding yet. We have studied charge carrier dynamics in active material of solar cell P3HT:ZnO along and perpendicular to the chain by means of longitudinal field (LF) muon-spin-relaxation (μSR) method to elucidate the intra and inter-chain charge carrier in polymer hybrid P3HT:ZnO. We found the charge carrier transport changes from intra-chain to inter-chain diffusion. One dimensional intra-chain diffusion is observed in the samples at low temperatures, while three dimensional inter-chain is observed at high temperatures.

Preparation of ZnO nanoparticles for blend of P3HT:ZnO nanoparticles:PCBM thin film and its charge carrier dynamics characterization

Recently, many researchers have paid attention to develop active material of solar cell which plays an important role in absorbing solar spectrum. This active material should have an ability to transfer charge carrier resulted from the absorption of solar spectrum. The hybrid organic-inorganic solar cell has been developed due to the combining advantages between organic material Poly(3-hexylthiophene) (P3HT) and fullerene PCBM with inorganic material ZnO nanoparticles. The investigation of charge carrier dynamics in blend P3HT:ZnO nanoparticles:PCBM film as an active material of solar cell devices is an important things to enhance the solar cell performance. The charge carrier dynamics properties is needed to control the morphology of active material to produce an efficient and effective charge dissociation. In this study we synthezed the ZnO nanoparticles by using sol-gel methods. The size of nanoparticles resulted from the reflux process of zinc acetate in methanol by the presence of catalist sodium hyd...

Influences of Al dopant atoms to the structure and morphology of Al doped ZnO nanorod thin film

We report our work about dependency of Al dopant atoms to the growth process of Al doped ZnO (AZO) nanorod structure. ZnO is one of type metal oxide, which is classified as semiconducting material with direct wide band gap (~ 3.4 eV). This metal oxide is widely used in optoelectronic devices, such as solar cell, gas sensing, and photocatalyst. To produce effective photoelectrode in solar cell devices and high sensitive sensor in gas sensing application, many researchers have been modifying the nanostructure, such as inserting dopant ions, variation in deposition technique and surface modifications. By inserting some dopant ions/atoms, the structure and morphology of ZnO nanorod can be controlled. Nucleation process of nanorod structure which is growth by chemical solution method, are depend on seed layer morphology. We have prepared ZnO nanorod thin film (growth by self-assembly method) with inserting aluminum as dopant atom both in seed layer and nanorod growth solution. The morphology of ZnO nanostructured significantly changes as the existence of aluminum atoms. Based on X-ray diffraction pattern, the wurtzite structures of AZO nanorod still possessed and only affect to the small shift of lattice crystal. A high surface roughness of seed layer can produce wide radius of nanorod, since the nucleation process initiated by seed layer particle size as a template of nanorod arrangement.

Effect of light exposure on the μSR asymmetry of graphene oxide film

Graphene has received a lot of attention due to its promising properties for electronic devices application such as energy storage device. Due to the amount needed for application, graphene oxide is widely used as a precursor to obtain graphene-like material. The GO film is thermally reduced or photoreduced to obtain graphene-like that known as reduced graphene oxide (rGO). We intend to measure microscopic intrinsic charge carrier motion of GO film by means of muon spin rotation relaxation (μSR). We prepared thick film of GO by stacking a lot of GO sheets using 4 mg/ml GO-water dispersion. The rGO material was obtained by thermally reduced GO film at 200°C for 2 hours under argon flowing. We measured zero field (ZF) μSR measurements of GO and rGO from 10 K and 300 K. During the μSR measurement we exposed the light into the samples. We discuss the effect of light exposure on the μSR asymmetry and compare to μSR asymmetry of rGO sample.

Self-Assembly of ZnO-Nanorods and Its Performance in Quasi Solid Dye Sensitized Solar Cells

Zinc oxide (ZnO) nanorods (NRs) were successfully prepared by self-assembly methods using zinc nitrate hexahydrate and hexamethylenetetramine as raw materials. ZnO-NRs were grown on FTO/ZnO seed layer and to enhance dye adsorption it was continued by deposition of titania (TiO2) paste by screen printing method. Deposition time of ZnO-NRs were varied, for 120, 150 and 180 minutes and subsequently stacked with one layer of TiO2 mesoporous. The resulting heterojunction layers of FTO/ZnO-Nrs/TiO2 was then applied as a photoanode in quasi-solid dye sensitized solar cell (QS- DSSC) with polymer gel electrolyte (PGE) as a hole conductor. UV-Vis spectrometer was used to investigate the changes of dye adsorption in photoanode with/without inserting titania mesoporous. Characterizations of scanning electron microscopy (SEM) and X-ray diffraction was carried out and the results shows that increasing the deposition time produces a smaller average grain size, diameter and denser layer of ZnO-nanorods. From current-voltage measurement, higher efficiency (η = 2.53%) was obtained for 120 min ZnO nanorods with short circuit current density (Jsc ) of 2.84 mA/cm2 and open circuit voltage (Voc) of 0.7 V. The combination of TiO2 and ZnO-NRs shows a better performance in solar cells characteristics due to increases of dye adsorption on photoanode and high photogenerated electron transport rate. This work emphasizes an optimum condition of ZnO-NRs in combination with TiO2 mesoporous as an alternative photoanode in QS-DSSC.

Zinc Oxide/TiO2 Bilayer Heterojunction as a Working Electrode in Quasi Solid Dye Sensitized Solar Cells

Bilayer heterojunction of aluminium doped zinc oxide (AZO) and titanium dioxide (TiO2) mesoporous has been successfully deposited on fluorine tin oxide (FTO) substrate as working electrode in dye sensitized solar cell. This layer was used as working electrode in quasi solid dye sensitized solar cell. The solar cell structure is FTO/ZnO/TiO2/PGE/Pt/FTO using polymer gel electrolyte (PGE). In polymer gel electrolyte system, hybrid copolymer based on poly-TMSPMA (3-methoxysilyl propyl methacrylate) was used as a matrix to trap ionic liquid. An addition of aluminum as atom dopant also studied to observe the physical properties changes of photoanode related to solar cell performance. AlCl3 was used as dopant material with the concentrations at 0.5 weight % and 1.0 weight% of zinc acetate dehydrate as raw material. Based on our previous result, the existence of Al dopant would decrease the surface roughness of ZnO layer, reduce the grain size of ZnO particles, transmittance at visible light increase and also change the charge carrier density. Nevertheless, the highest efficiency was achieved for undoped ZnO/TiO2 photoanode (η=0.67%). Based on current-voltage measurement data analysis (using diode model equation) the ideality factor (n) of device using undoped ZnO was smaller (n=2.96) than AZO 0.5 wt% and 1.0 wt% (n=~4), indicate better quality of undoped ZnO/TiO2 interfaces rather than AZO/TiO2.

Reduction Kinetics of Thermally Reduced Graphene Oxide Thin Films

We report an experimentalstudy of thermal reduction of graphene oxide (GO) under nitrogen flow.Ultrathin films of GO were prepared on quartz glass substrates by spin-coatingfrom 3 mg/ml aqueous solutions of GO. These films were annealed at 50 °C under vacuum overnight before thermal reduction.The films were exposed to temperatures of 100 °C, 150 °C, 200 °C, 300 °C, 400 °C, 500 °C and 800 °C under nitrogen flowing. We used UV-Vis absorption spectroscopy tomonitor the change of absorption spectra caused by thermal reduction. We observed a significant change ofabsorption spectra due to formation of reduced graphene oxide (RGO). We found that thermal reduction startedalready at 100 °C, but proceeded significantly faster at heating temperatures higherthan 200 °C.

μSR Study of Charge Carrier Motion in Active Layer P3HT:ZnO:PCBM Hybrid Solar Cells

The so-called hybrid (organic-inorganic) solar cell has been developed due to the combining advantage between organic material such as Poly(3-hexylthiohene)/P3HT and inorganic material such as zinc oxide (ZnO). By adding fullerene derivative (6,6-phenyl-C61-butyric acid methyl ester/PCBM) to the hybrid solar cell, the performance of solar cell is predicted to be increased. We have studied the charge carrier motion in blend of P3HT:ZnO:PCBM using LF-μSR with and without light irradiation to clarify the charge carrier motion in bulk ternary system of hybrid material. We found that charge carrier motion in P3HT:ZnO:PCBM changes from intra-chain to inter-chain diffusion. One-dimensional intra-chain diffusion is observed in the sample at low temperature below 15 K, while three-dimensional inter-chain is observed at high temperature above 25 K.

Study of Charge Carrier Dynamics of P3HT:PCBM Blend for Active Material Solar Cell Using Muon Spin Relaxation

Poly (3-hexylthiohene) (P3HT) has attracted much attention due to their chemical and thermal stability as well as their potential to be used as an active material in solar cells. Recently, bulk-heterojunction BHJ solar cell has been intensively developed due to its potential for high power conversion efficiency and low cost solar cells. Many studies have been done to understand the effect of PCBM to the morphology of the P3HT:PCBM blend and to performance of its solar cells. However, the clearly explanation about the effect of PCBM to the charge carrier dynamics in P3HT is not well understood yet. We have studied charge carrier dynamics in active material of solar cell P3HT:PCBM along and perpendicular to the chain by means of longitudinal field (LF) muon-spin-relaxation (μSR) method to elucidate the intra and inter-chain charge carrier in polymer hybrid P3HT:PCBM. We found the charge carrier transport changes from intra-chain to inter-chain diffusion. One dimensional intra-chain diffusion is observed in the samples at low temperatures below 10K, while three dimensional inter-chain is observed at high temperatures above 15K. This temperature is lower than that of P3HT only.

Effect of Solvent Used in the Preparation of Aluminum-Doped ZnO as Electron Acceptor Layer on the Characteristic of its Hybrid Solar Cell

Aluminum doped Zinc Oxide (AZO) layer has been employed as electron acceptor in hybrid solar cell based on Poly(3-hexylthiophene) with inverted structure. AZO layers used in this work were prepared by sol-gel process using two different solvents, namely methanol and methoxyethanol. From X-ray diffraction measurements, AZO layer prepared using methanol solvent (AZO-me) indicates the formation of crystallines with the same (002) orientation, whereas AZO layer prepared using methoxyethanol (AZO-mx) indicates the formation of crystallines with (100), (002), and (101) orientations. The nanomorphology of those AZO layer surfaces was also remarkably different, which might be related to differences in crystal orientation. For both solvents, the photocurrent density-voltage (J-V) characteristics were also affected by the Al ion concentration in AZO layer. However, solar cell with AZO-mx shows better performances in comparison to that of AZO-me with the same Al ion concentration. The observation of performance variations in those fabricated solar cells are suggested to be strongly related with the crystal orientation and nanomorphology of AZO layer. These experimental results then suggest that charge carrier dissociation by AZO layer are significantly influenced by the crystal orientation and nanomorphology of AZO layer, which are affected by the solvent used for preparing the AZO layer.