Photovoltaic properties in poly(3-alkylthiophene) based heterojunction cells (original) (raw)
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Solar Energy Materials and Solar Cells, 2006
Electrical and photovoltaic properties of donor-acceptor composite system comprised of poly (3-phenyl azo methine thiophene) (PPAT) and 1, 1 0 -diallyl substituted 4, 4 0 -dipyridine (DADP) were investigated. A significant enhancement of photocurrent was observed when PPAT was blended with DADP. The increase in photocurrent has been explained in terms of efficient charge separation that resulted from the transfer of photo-excited electrons from PPAT to DADP. The strong quenching of fluorescence of PPAT was caused by the presence of DADP that indicates the photo-induced charge transfer from PPAT to DADP. The open circuit voltage (V oc ) generated in the device is independent of the variation of work function of negative metal electrode that has been explained in terms of Fermi level pinning between DADP and metal via surface charges. The electrical characteristics of ITO/PPAT: DADP/Al photovoltaic device were determined by analyzing the dependence of short circuit photocurrent density (J sc ) and V oc under illumination at different temperatures. The V oc decreases almost linearly with increasing temperature, while short-circuit photocurrent increases logarithmically with temperature and saturates at higher temperature above 330 K. This dependence of J sc and V oc on temperature has been discussed in terms of possible mechanism that involves the ARTICLE IN PRESS www.elsevier.com/locate/solmat 0927-0248/$ -see front matter r photovoltage generation and charge carrier transport in the device under thermally activated state. The photovoltaic device made from PPAT: DADP blend has shown three times higher photosensitivity than that of made from pure PPAT. r
Advanced Functional Materials, 2011
The optoelectronic and photophysical properties of four regioregular poly[3-(carboxyalkyl)thiophene-2,5-diyl] (P3CAT) with different carboxyalkyl chain lengths (propyl to hexyl) are reported. Each P3CAT is combined with [6,6]-phenyl-C 61-butyric acid methyl ester to form the photoactive bulk heterojunction layer for organic photovoltaic devices. The extent of hydrogen bonding and polymer crystallinity in the fi lms has been determined through infrared spectroscopy and X-ray diffraction. The mechanical properties of fi lms are analyzed with nanoindentation, and the measurements suggest that P3CATs are suitable for use in fl exible devices. Power conversion effi ciencies of up to 2.6% and 1.6% are obtained for devices fabricated in air, and supported on glass and fl exible poly(ethylene terephthalate) substrates, respectively.
Improvement of Poly(3-phenylthiophene)Based Bulk Heterojunction Organic Solar Cells
Molecular Crystals and Liquid Crystals, 2011
This paper describes the synthesis and photovoltaic studies of Poly(3-Phenylthiophene) (P3PhT). P3PhT was synthesized by the chemically oxidized polymerization in the presence of FeCl3. Bulk heterojunction solar cells based on polymer were fabricated by using chloroform, chlorobenzene, and dichlorobenzene at different weight ratios of P3PhT. The different ratios of P3PhT as the electron donor blended with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) as the electron acceptor were investigated. A maximum power conversion efficiency was achieved at a 2:3 (wt:wt) P3PhT:PC61BM blend ratio in dichlorbenzene.
Organic Electronics, 2005
In this report regioregular poly(3-alkylthiophenes) (P3ATs) (P3HT: poly(3-hexylthiophene, P3OT: poly(3-octylthiophene, P3DDT: poly(3-dodecylthiophene) were studied regarding their optical and electrochemical properties and used as electron donors in polymer solar cells. The optical band gap energy for the three polymers amounts to 1.92 eV. With longer side chain length their electrochemical band gaps are slightly increased, whereas the absorption coefficient undergoes a systematic decrease. The absorption spectra of the pristine P3ATs exhibit a distinctive blue shift of the p-p* interband transition upon mixing with PCBM 1:3 (as prepared films; P3HT: 45nm,P3OT:45 nm, P3OT: 45nm,P3OT:85 nm, P3DDT: $50 nm). Films based on composites of the three polymers with PCBM ([6, 6]-phenyl-C61-butyric acid methyl ester) show a distinctive photoluminescence quenching effect. At 77 K two types of light-induced electron spin resonance (LESR) signals were identified, one of polaron (P +Å ) on the polymer chain and one of PCBM ÀÅ radical anion, which detect the photoinduced charge generation and charge transfer in P3AT/PCBM composites.
Journal of Non-crystalline Solids, 2008
The organic solar cell based on poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)/ pentacene (Pc) was fabricated using a flexible polyethyleneterephthalate (PET) substrate coated with conductive ITO layer and aluminum contact film formed on a Pc layer by electron beam deposition. The performed investigations of current-voltage characteristics indicate that the devices operate like Schottky diodes. Under illumination of an ITO/PEDOT:PSS/Pc/Al multilayer structure the photovoltaic effect is measured with open circuit voltages up to 0.5 V, short circuit current of 0.6 lA and fill factor 0.2. The spectral-photocurrent excitation profile covers a full range of visible light (380-700 nm).
ACS Applied Materials & Interfaces, 2010
This contribution describes the design, synthesis, characterization, and organic photovoltaic (OPV) device implementation of a novel interfacial layer (IFL) for insertion between the anode and active layer of poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C 61butyric acid methyl ester (PCBM) bulk-heterojunction solar cells. The IFL precursor, 5,5′-bis[(p-trichlorosilylpropylphenyl)phenylamino]-2,2′-bithiophene (PABTSi 2 ), covalently anchors to the Sn-doped In 2 O 3 (ITO) surface via the -SiCl 3 groups and incorporates a bithiophene unit to align the highest occupied molecular orbital (HOMO) energy with that of P3HT (5.0 eV). The synthesis and subsequent electrochemical analysis of PABTSi 2 indicates a HOMO energy of 4.9 eV, while the lowest uoccupied molecular orbital level remains sufficiently high, at 2.2 eV, to effectively block electron leakage to the OPV ITO anode. For the P3HT:PCBM OPV fabrication, PABTSi 2 is used as a spin-coated cross-linked (via -SiCl 3 hydrolysis and condensation) 1:2 blend with poly [9,9-dioctylfluorene-co-N-[4-(3methylpropyl)]-diphenylamine] (TFB). Such devices exhibit an average power conversion efficiency of 3.14%, a fill factor of 62.7%, an open-circuit voltage of 0.54 V, and a short-circuit current of 9.31 mA/cm 2 , parameters rivaling those of optimized PEDOT:PSSbased devices.
Polythiophene based bulk heterojunction solar cells: Morphology and its implications
2006
The performance of bulk heterojunction organic solar cells based on Poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1phenyl-(6,6)C61 (PCBM) processed from chlorobenzene solution can be enhanced by a thermal treatment of the device. The morphology of films made from 1 / 2 wt. ratio blends of P3HT and PCBM reveals an unfavorable amorphous phase in the as-produced cells while after annealing a more favorable crystalline phase is obtained. Through variation of the processing solvent a power conversion efficiency of 3.6% is demonstrated without the necessity of an additional annealing step. It is shown that the as-produced active layer already has a crystalline morphology. We argue that the high boiling point of the solvent plays an important role in this by influencing the evaporation speed during deposition of the active layer. Further proof is delivered that indeed slowing down the evaporation speed can beneficially influence the solar cell performance. D
Realization and Characterization of P-typed Polythiophene Based Organic Photovoltaic Cells
Journal of Nano- and Electronic Physics, 2018
In this work, an organic photovoltaic cell experimental study was performed to improve the electrical characteristics (current and voltage) and the conversion efficiency. Three Schottky organic photovoltaic cells that based polythiophene are realized experimentally for several cell surfaces and transparent electrode types. According to the obtained results, the best conversion efficiency is registered for the organic cell fabricated by {ZnO:Al/PTH/Al}. The photovoltaic cell performances are highly dependent on their geometry and the rearrangement of the polymer grains in contact with the metal that reflects the surface state significance of the two parts (metal and polymer). The electrode type used in the cell manufacturing possesses a very important influence on the cell electrical characteristics.
Applied Physics Letters, 2008
Poly͑2,5-bis͑3-tetradecyllthiophen-2-yl͒thieno͓3,2-b͔thiophene͒ ͑pBTTT͒ has caused recent excitement in the organic electronics community because of its high reported hole mobility ͑0.6 cm 2 V −1 s −1 ͒ that was measured in field effect transistors and its ability to form large crystals. In this letter, we investigate the potential of pBTTT as light absorber and hole transporter in a bulk heterojunction solar cell. We find that the highest efficiency of 2.3% is achieved by using a 1:4 blend of pBTTT and͓6,6͔-phenyl C 61-butyric acid methyl ester. The hole mobility as measured by space charge limited current modeling was found to be 3.8ϫ 10 −4 cm 2 V −1 s −1 in this blend.