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1.
To improve the power conversion efficiency (PCE) of small molecular weight organic photovoltaic cells (OPVs) it is proposed to use a simple fabrication method by controlling the deposition rate of the acceptor material fullerene (C60) in planar heterojunction OPV structures of ITO/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)/copper phthalocyanine (CuPc)/C60/bathocuproine (BCP)/Ag. In our optimised device, the highest PCE of 1.7% was obtained through a deposition rate of C60 equal to 0.3 nm/s due to the superior charge balance in the CuPc/C60 heterojunction. Such a charge balance condition increased the fill factor from 52.4% to 56.1% by reducing the carrier accumulation in the OPV device. The electron only device was fabricated with the purpose of analysing the electron mobility of C60 as a function of the deposition rate. In addition, the effects of the deposition rates on the performance of planar OPV devices were exhaustively analysed by examining the absorption properties and the surface morphologies.  相似文献   

2.
Summary : Perylene derivatives, that behave as liquid crystal and might be used as electron acceptors, and poly(tetrabromo-p-phenylenediselenide) (PTBrPDSe) were synthesized with the purpose of using the polymer as buffer layer in solar cells. It was demonstrated that perylene compounds of N,N′-diheptyl-3,4,9,10-perylentetracarboxyldiimide (PTCDI-C7) and N,N′-diundecyl-3,4,9,10-perylentetracarboxyldiimide (PTCDI-C11) enabled obtaining photovoltaic effect when coupled with copper phthalocyanine (CuPc). The power conversion efficiency of the cells prepared from these perylenes is similar, whatever the x value. However this efficiency is smaller than the one achieved when the couple CuPc/C60 (fullerene) is used. More precisely, the best efficiency was obtained when a PTBrPDSe/Au buffer layer is introduced between the ITO anode and the CuPc. It was established that the presence of the thin PTBrPDSe layer allows improving the shunt resistance and consequently the cells performance.  相似文献   

3.
Organic solar cells with inverted planar heterojunction structure based on subphthalocya-nine and C60 were fabricated using several kinds of materials as cathode buffer layer (CBL), including tris-8-hydroxy-quinolinato aluminum (Alq3), bathophenanthroline (Bphen), bathocuproine, 2,3,8,9,14,15-hexakis-dodecyl-sulfanyl-5,6,11,12,17,18-hexaazatrinaphthylene (HATNA), and an inorganic compound of Cs2CO3. The influence of the lowest unoccupied molecular orbital level and the electron mobility of organic CBL on the solar cells perfor-mance was compared. The results showed that Alq3, Bphen, and HATNA could significantly improve the device performance. The highest efficiency was obtained from device with an-nealed HATNA as CBL and increased for more than 7 times compared with device without CBL. Furthermore, the simulation results with space charge-limited current theory indicated that the Schottky barrier at the organic/electrode interface in inverted OSC structure was reduced for 27% by inserting HATNA CBL.  相似文献   

4.
New solar cells with Ag/C60/MAPbI3/Cu2ZnSnSe4 (CZTSe)/Mo/FTO multilayered structures on glass substrates have been prepared and investigated in this study. The electron-transport layer, active photovoltaic layer, and hole-transport layer were made of C60, CH3NH3PbI3 (MAPbI3) perovskite, and CZTSe, respectively. The CZTSe hole-transport layers were deposited by magnetic sputtering, with the various thermal annealing temperatures at 300 °C, 400 °C, and 500 °C, and the film thickness was also varied at 50~300 nm The active photovoltaic MAPbI3 films were prepared using a two-step spin-coating method on the CZTSe hole-transport layers. It has been revealed that the crystalline structure and domain size of the MAPbI3 perovskite films could be substantially improved. Finally, n-type C60 was vacuum-evaporated to be the electronic transport layer. The 50 nm C60 thin film, in conjunction with 100 nm Ag electrode layer, provided adequate electron current transport in the multilayered structures. The solar cell current density–voltage characteristics were evaluated and compared with the thin-film microstructures. The photo-electronic power-conversion efficiency could be improved to 14.2% when the annealing temperature was 500 °C and the film thickness was 200 nm. The thin-film solar cell characteristics of open-circuit voltage, short-circuit current density, fill factor, series-resistance, and Pmax were found to be 1.07 V, 19.69 mA/cm2, 67.39%, 18.5 Ω and 1.42 mW, respectively.  相似文献   

5.
A series of sublimable substituted chlorotricarbonyl bis(phenylimino)acenaphthene rhenium(I) complexes was synthesized and used in the fabrication of photovoltaic devices. The hole and electron carrier mobilities of these complexes are in the order of 10−3 to 10−4 cm2 V−1 s−1. Heterojunction devices with CuPc/complex/C60 (CuPc = copper phthalocyanine) as the active layer and bulk heterojunction devices with complex:C60 as the active layer were fabricated. The rhenium complexes function as photosensitizer in the devices, and exhibit optical absorption in the region between 500 and 550 nm within which other components in the device do not absorb. Other devices with hole transport materials, exciton blocking materials, and different active layer thickness were also fabricated. Variation of substitution groups in the ligand did not show significant difference in device performance. The best power conversion efficiency of the devices was measured to be 1.29% under illumination of AM1.5 simulated solar light.  相似文献   

6.
Organic photovoltaic (OPV) cells were fabricated via vacuum vapor deposition with {4-[2-(3-di-cyanomethylidene-5,5-dimethylcyclohexenyl)vinyl]phenyl}di(1-naphthyl)amine (DNP-2CN) as the electron donor, and fullerene (C60) as the electron acceptor. A thin film (10 nm) of tris(8-quinolinolato)aluminum (Alq3) was adopted as the buffer layer. A device based on this DNP-2CN exhibited an open circuit voltage (Voc) of 370 mV, a short-circuit current density (Jsc) of 0.61 mAocm 2, and a white-light power conversion efficiency ( η) of 0.09% (AM1.5, 75 mW.cm^- 2).  相似文献   

7.
Oligophenylenevinylene (OPV)‐terminated phenylenevinylene dendrons G1 – G4 with one, two, four, and eight “side‐arms”, respectively, were prepared and attached to C60 by a 1,3‐dipolar cycloaddition of azomethine ylides generated in situ from dendritic aldehydes and N‐methylglycine. The relative electronic absorption of the OPV moiety increases progressively along the fullerodendrimer family C60G1 – C60G4 , reaching a 99:1 ratio for C60G4 (antenna effect). UV/Vis and near‐IR luminescence and transient absorption spectroscopy was used to elucidate photoinduced energy and electron transfer in C60G1 – C60G4 as a function of OPV moiety size and solvent polarity (toluene, dichloromethane, benzonitrile), taking into account the fact that the free‐energy change for electron transfer is the same along the series owing to the invariability of the donor–acceptor couple. Regardless of solvent, all the fullerodendrimers exhibit ultrafast OPV→C60 singlet energy transfer. In CH2Cl2, the OPV→C60 electron transfer from the lowest fullerene singlet level (1C60*) is slightly exergonic (ΔGCS≈0.07 eV), but is observed, to an increasing extent, only in the largest systems C60G2 – C60G4 with lower activation barriers for electron transfer. This effect has been related to a decrease of the reorganization energy upon enlargement of the molecular architecture. Structural factors are also at the origin of an unprecedented OPV→C60 electron transfer observed for C60G3 and C60G4 in apolar toluene, whereas in benzonitrile, electron transfer occurs in all cases. Monitoring of the lowest fullerene triplet state by sensitized singlet oxygen luminescence and transient absorption spectroscopy shows that this level is populated through intersystem crossing and is not involved in photoinduced electron transfer.  相似文献   

8.
We developed a method to improve the performance of the copper phthalocyanine (CuPc)/fullerene (C60) organic solar cells (OSCs) by doping CuPc with a long triplet lifetime material. By doping [Cu(bis[2-(diphenylphosphino)phenyl]ether)(benzo[i]dipyrido[3,2-a:2′,3′-c]phenazine)]BF4 (CuDB) into CuPc, the enhanced short-circuit current density (JSC) of 6.213 mA/cm2, open-circuit voltage (VOC) of 0.39 V and a peak power conversion efficiency (PCE) of 0.92% compared to 0.79% of the standard CuPc/C60 OSCs are achieved under 1 sun AM 1.5 G illumination at an intensity of 100 mW/cm2. The performance improvement is mainly attributed to the long triplet lifetime of CuDB (τ = 70.05 μs) which leads to more effective exciton dissociation.  相似文献   

9.
Nanospheres of Ag‐coated Fe3O4 were successfully synthesized and characterized. Photocatalytic properties of Fe3O4@Ag composites have been investigated using steady‐state studies and laser pulse excitations. Accumulation of the electrons in the Ag shell was detected from the shift in the surface plasmon band from 430 to 405 nm, which was discharged when an electron acceptor such as O2, Thionine (TH) or C60 was introduced into the system. Charge equilibration with redox couple such as C60●–/C60 indicated the ability of these core–shell structures to carry out photocatalytic reduction reactions. As well, outer Ag layer could boost charge separation in magnetic core through dual effects of Schottky junction and localized surface plasmonic resonance (LSPR)‐powered band gap breaking effect under sunlight irradiation; resulted in higher photocatalytic degradation of diphenylamine (DPA). The maximum photocatalytic degradation rate was achieved at optimum amount of Ag‐NP loading to products. Adsorption studies confirmed that degradation of DPA dominantly occurred in solution. Moderately renewability of the nanocatalysts under sunlight was due to oxidation and dissolution of the outer Ag layer.  相似文献   

10.
A new and highly efficient cathode interlayer material for organic photovoltaics (OPVs) was produced by integrating C60 fullerene monomers into ionene polymers. The power of these novel “C60‐ionenes” for interface modification enables the use of numerous high work‐function metals (e.g., silver, copper, and gold) as the cathode in efficient OPV devices. C60‐ionene boosted power conversion efficiencies (PCEs) of solar cells, fabricated with silver cathodes, from 2.79 % to 10.51 % for devices with a fullerene acceptor in the active layer, and from 3.89 % to 11.04 % for devices with a non‐fullerene acceptor in the active layer, demonstrating the versatility of this interfacial layer. The introduction of fullerene moieties dramatically improved the conductivity of ionene polymers, affording devices with high efficiency by reducing charge accumulation at the cathode/active layer interface. The power of C60‐ionene to improve electron injection and extraction between metal electrodes and organic semiconductors highlights its promise to overcome energy barriers at the hard‐soft materials interface to the benefit of organic electronics.  相似文献   

11.
Electrochemical reactors that electrolytically convert CO2 into higher-value chemicals and fuels often pass a concentrated hydroxide electrolyte across the cathode. This strongly alkaline medium converts the majority of CO2 into unreactive HCO3 and CO32− byproducts rather than into CO2 reduction reaction (CO2RR) products. The electrolysis of CO (instead of CO2) does not suffer from this undesirable reaction chemistry because CO does not react with OH. Moreover, CO can be more readily reduced into products containing two or more carbon atoms (i. e., C2+ products) compared to CO2. We demonstrate here that an electrocatalyst layer derived from copper phthalocyanine ( CuPc ) mediates this conversion effectively in a flow cell. This catalyst achieved a 25 % higher selectivity for acetate formation at 200 mA/cm2 than a known state-of-art oxide-derived Cu catalyst tested in the same flow cell. A gas diffusion electrode coated with CuPc electrolyzed CO into C2+ products at high rates of product formation (i. e., current densities ≥200 mA/cm2), and at high faradaic efficiencies for C2+ production (FEC2+; >70 % at 200 mA/cm2). While operando Raman spectroscopy did not reveal evidence of structural changes to the copper molecular complex, X-ray photoelectron spectroscopy suggests that the catalyst undergoes conversion to a metallic copper species during catalysis. Notwithstanding, the ligand environment about the metal still impacts catalysis, which we demonstrated through the study of a homologous CuPc bearing ethoxy substituents. These findings reveal new strategies for using metal complexes for the formation of carbon-neutral chemicals and fuels at industrially relevant conditions.  相似文献   

12.
A divergent method for the synthesis of α,α′‐diarylacenaphtho[1,2‐c]phosphole P‐oxides has been established; α,α′‐dibromoacenaphtho[c]phosphole P‐oxide, which was prepared through a TiII‐mediated cyclization of 1,8‐bis(trimethylsilylethynyl)naphthalene, underwent a Stille coupling with three different kinds of aryltributylstannanes to afford the α,α′‐diarylacenaphtho[c]phosphole P‐oxides in moderate to good yields. X‐ray crystallographic analyses and UV/Vis absorption/fluorescence measurements have revealed that the degree of π‐conjugation, the packing motif, the electron‐accepting ability, and the thermal stability of the acenaphtho[c]phosphole π‐systems are finely tunable with the α‐aryl substituents. All the P?O and P?S derivatives exhibited high stability in their electrochemically reduced state. To use this class of arene‐fused phosphole π‐systems as n‐type semiconducting materials, we evaluated device performances of the bulk heterojunction organic photovoltaics (OPV) that consist of poly(3‐hexylthiophene), an indene‐C70 bisadduct, and a cathode buffer layer. The insertion of the diarylacenaphtho[c]phosphole P‐oxides as the buffer layer was found to improve the power conversion efficiency of the polymer‐based OPV devices.  相似文献   

13.
Summary: Ambipolar transport has been realised in blends of the molecular hole conductor Cu-phthalocyanine (CuPc) and the electron conducting fullerene C60. Charge carrier mobilities and the occupied electronic levels have been analyzed as a function of the mixing ratio using field-effect transistor measurements and photoelectron spectroscopy. These results are discussed in the context of photovoltaic cells based on these materials.  相似文献   

14.
Electron transport materials (ETM) play an important role in the improvement of efficiency and stability for inverted perovskite solar cells (PSCs). This work reports an efficient ETM, named PDI‐C60, by the combination of perylene diimide (PDI) and fullerene. Compared to the traditional PCBM, this strategy endows PDI‐C60 with slightly shallower energy level and higher electron mobility. As a result, the device based on PDI‐C60 as electron transport layer (ETL) achieves high power conversion efficiency (PCE) of 18.6 %, which is significantly higher than those of the control devices of PCBM (16.6 %) and PDI (13.8 %). The high PCE of the PDI‐C60‐based device can be attributed to the more matching energy level with the perovskite, more efficient charge extraction, transport, and reduced recombination rate. To the best of our knowledge, the PCE of 18.6 % is the highest value in the PSCs using PDI derivatives as ETLs. Moreover, the device with PDI‐C60 as ETL exhibits better device stability due to the stronger hydrophobic properties of PDI‐C60. The strategy using the PDI/fullerene hybrid provides insights for future molecular design of the efficient ETM for the inverted PSCs.  相似文献   

15.
Electroluminescent devices were fabricated using plasma-polymerized carbon disulfide films, poly(CS2), and tris(8-quinolinolato)aluminum(III) complex, Alq, as the hole transport layer and the emitting layer, respectively. A cell structure of glass substrate/indium–tin–oxide/poly(CS2/Alq/Mg/Ag) was employed. Smooth hole injection from the electrode through the poly(CS2) layer and concomitant electroluminescence from the Alq layer were observed. Green emission with a luminance of 250 cd/m2 was achieved at a drive voltage of 14 V.  相似文献   

16.
A fast, simple and sensitive square-wave voltammetric (SWV) method for the determination of trace amounts of furazolidone (FZ) in urine is reported. A three-electrode system containing stationary mercury dropping (SMDE) working electrode, Pt auxiliary electrode and Ag/AgCl reference electrode was used throughout. Briton-Rabinson buffer solution is used as both pH adjusting agent and supporting electrolyte. The calibration graph showed good linearity in the concentration range of 20–900 ng ml?1 of furazolidone with a regression coefficient of 0.9996. The equation Δ(i) = 0.0095CFZ + 0.234 was used for calculation of furazolidone concentration in the sample solution, where CFZ is the concentration of furazolidone in ng ml?1 and Δ(i) is the difference between voltammogram peak currents of sample and blank solution. The RSD for 8 replicate measurements of a 60 ng ml?1 solution and LOD of the proposed method were found to be 2.2% and 5.2 ng ml?1, respectively. The procedure was successfully applied to the determination of furazolidone in urine samples.  相似文献   

17.
Pristine fullerene C60 is an excellent electron transport material for state-of-the-art inverted structure perovskite solar cells (PSCs), but its low solubility leaves thermal evaporation as the only method for depositing it into a high-quality electron transport layer (ETL). To address this problem, we herein introduce a highly soluble bowl-shaped additive, corannulene, to assist in C60-assembly into a smooth and compact film through the favorable bowl-ball interaction. Our results show that not only corannulene can dramatically enhance the film formability of C60, it also plays a critical role in forming C60-corannulene (CC) supramolecular species and in boosting intermolecular electron transport dynamics in the ETL. This strategy has allowed CC devices to deliver high power conversion efficiencies up to 21.69 %, which is the highest value among the PSCs based on the solution-processed-C60 (SP-C60) ETL. Moreover, the stability of the CC device is far superior to that of the C60-only device because corannulene can retard and curb the spontaneous aggregation of C60. This work establishes the bowl-assisted ball assembly strategy for developing low-cost and efficient SP-C60 ETLs with high promise for fully-SP PSCs.  相似文献   

18.
In this article, controlled changes on morphology, thickness, and band gap of poly[ethylenedioxythiophene] (PEDOT) polymer films fabricated by electrochemical polymerization (potentiostatically) are analyzed. Electropolymerization of the monomer ethylenedioxythiophene (EDOT) was carried out on indium tin oxide (ITO) electrodes, in different dry organic electrolytic media, such as acetonitrile, acetonitrile–dichloromethane, and toluene–acetonitrile mixtures. It was found that electropolymerization kinetics can be controlled by changing the polarity of the electrolytic media, and kinetics is slower for those with low polarity. This fact combined with an accurate control of EDOT monomer concentration and electropolymerization at Epeak/2 potential, allows to control the morphology and thickness of the electropolymerized PEDOT films (E-PEDOT:ClO4); toluene/ACN (4:1, v/v) and [EDOT]?=?0.3 mM gave the best films for application in organic photovoltaic (OPV) cells. The performance of the E-PEDOT:ClO4 films was tested on ITO electrodes as anode buffer layer in OPV cells with the configuration ITO/E-PEDOT:ClO4/P3HT:PC61BM/Field’s metal, where Field’s metal (cathode) is a eutectic alloy that lets to fabricate OPV devices easily and in a fast and economical way at free vacuum conditions. The performance of these devices was compared with an OPV device constructed with a buffer layer anode, prepared using the classical spin coating of PEDOT:PSS on ITO. Results showed that OPV cells fabricated with E-PEDOT:ClO4 have a slightly increased PV performance.  相似文献   

19.
采用气固法制备了磷化钼-碳纳米花(MoP-CFs),通过简单的超声自组装将C60修饰在MoP-CFs表面,形成范德瓦耳斯异质结。研究其电催化析氢性能发现,C60的修饰能够有效降低电催化析氢过电位。其中,10% C60-MoP-CFs样品(10%为C60的质量分数)表现出最佳催化活性,在酸性和碱性条件下达到10 mA·cm-2的电流密度时,所需要的过电位分别为158和157 mV,并且具有至少20 h的电催化稳定性。C60与MoP-CFs之间强电子耦合作用促进电子由C60迁移到MoP-CFs表面,有助于减小电荷传输阻力,加快电催化析氢界面反应动力学过程。  相似文献   

20.
采用气固法制备了磷化钼-碳纳米花(MoP-CFs),通过简单的超声自组装将C60修饰在MoP-CFs表面,形成范德瓦耳斯异质结。研究其电催化析氢性能发现,C60的修饰能够有效降低电催化析氢过电位。其中,10% C60-MoP-CFs样品(10%为C60的质量分数)表现出最佳催化活性,在酸性和碱性条件下达到10 mA·cm-2的电流密度时,所需要的过电位分别为158和157 mV,并且具有至少20 h的电催化稳定性。C60与MoP-CFs之间强电子耦合作用促进电子由C60迁移到MoP-CFs表面,有助于减小电荷传输阻力,加快电催化析氢界面反应动力学过程。  相似文献   

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