摘要 :
The performance of organic photovoltaics (OPVs) based on the smallmolecule organic semiconductor p-DTS(FBTTh2)2 is greatly improved by the addition of a conjugated block copolymer composed of difluoroquinoxaline and thienopyrrolod...
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The performance of organic photovoltaics (OPVs) based on the smallmolecule organic semiconductor p-DTS(FBTTh2)2 is greatly improved by the addition of a conjugated block copolymer composed of difluoroquinoxaline and thienopyrrolodione blocks (D130). The power conversion efficiency (PCE) of the p-DTS(FBTTh2)2-based OPV is improved from 5.08% to 6.75% by the addition of 5 wt% D130 to the photoactive layer, which is composed of p-DTS(FBTTh2)2 and a fullerene derivative. Current-voltage and grazing incidence wide-angle X-ray scattering analyses revealed that the addition of D130 significantly reduces the trap density of the device and changes the packing orientation of p-DTS(FBTTh2)2 from mostly edge-on to partially faceon. These changes greatly improve the charge carrier mobility of the OPV, indicating that D130 is highly compatible with p-DTS(FBTTh2)2. Furthermore, the addition of D130 improve the photostability of the OPV by reducing the burn-in loss under a light soaking intensity of 1 sun. The D130-based OPV maintained 34% of its initial PCE after a light soaking test for 858 h. In contrast, the PCE of the OPV without D130 reduced to 14% of its initial efficiency in the same time period.
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In this work, we study the effect of the transparent conducting oxide (TCO) and the polymer applied (MEH-PPV or P_3HT) on the photovoltaic properties of TCO/TiO_2/polymer/Ag bi-layer solar cells. The solar cells were analyzed unde...
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In this work, we study the effect of the transparent conducting oxide (TCO) and the polymer applied (MEH-PPV or P_3HT) on the photovoltaic properties of TCO/TiO_2/polymer/Ag bi-layer solar cells. The solar cells were analyzed under inert atmosphere conditions resembling an encapsulated or sealed device. We demonstrate that the substrate applied, ITO or FTO, modifies the crystalline structure of the TiO_2: on an ITO substrate, TiO 2 is present in its anatase phase, on an FTO, the rutile phase predominates. Devices fabricated on an FTO, where the rutile phase is present, show better stability under inert atmospheres than devices fabricated on an ITO, anatase phase. With respect to the polymer, devices based on MEH-PPV show higher Voc (as high as 1 V), while the application of P3HT results in lower Voc, but higher Jsc and longer device stability. These observations have been associated to (a), the crystalline structure of TiO_2 and (b) to the form the polymer is bonded to the TiO_2 surface. In-situ IPCE analyses of P3HT-based solar cells show a red shift on the peak corresponding to TiO_2, which is not present on the MEH-PPV-based solar cells. The latter suggest that P3HT can be linked to the TiO_2 though the S-end atom, which results in devices with lower Voc. All these observations are also valid for devices, where the bare TiO_2 is replaced by an NbTiO _2. The application of an NbTiO_2 with rutile structure in these polymer/oxide solar cells is the reason for their higher stability under inert atmospheres. We conclude that the application of TiO_2 in its rutile phase is beneficial for long-term stability devices. Moreover there is an interplay between low Voc and Jsc in devices applying P_3HT, since power conversion efficiency can be partially canceled by their lower Voc in comparison with MEH-PPV. These findings are important for polymer/oxide solar cells, but also for organic solar cells, where a layer of semiconductor oxides are in direct contact with a polymer, like in an inverted or tandem organic solar cells.
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摘要 :
Solar cells transparent in the visible range are highly requested for integration in
see-through photovoltaic (PV) applications such as building glass façades or
greenhouse roofs. The development of advanced transparent PV can ...
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Solar cells transparent in the visible range are highly requested for integration in
see-through photovoltaic (PV) applications such as building glass façades or
greenhouse roofs. The development of advanced transparent PV can fully exploit
the tandem technology where the top cell absorbs the near-ultraviolet solar
spectrum while the bottom one absorbs the near-infrared part. Herein, a possible
implementation of this tandem PV paradigm, namely, the tandem structure
composed of a high-bandgap halide perovskite solar cell and a low-bandgap
organic solar cell, is considered. Electro-optical simulation results based on
parameters calibrated on experimental data show that an efficiency of 15% can be
achieved with an average visible transmittance above 50%. This can be obtained
considering the halide perovskite with mixed chlorine and bromine anions, a
nonfullerene-based bulk heterojunction, a well-calibrated light management, and
a three-terminal configuration of the tandem.
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摘要 :
The efficiency of organic solar cells can benefit from multijunction device architectures, in which energy losses are substantially reduced. Herein, recent developments in the field of solution-processed multijunction organic sola...
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The efficiency of organic solar cells can benefit from multijunction device architectures, in which energy losses are substantially reduced. Herein, recent developments in the field of solution-processed multijunction organic solar cells are described. Recently, various strategies have been investigated and implemented to improve the performance of these devices. Next to developing new materials and processing methods for the photoactive and interconnecting layers, specific layers or stacks are designed to increase light absorption and improve the photocurrent by utilizing optical interference effects. These activities have resulted in power conversion efficiencies that approach those of modern thin film photovoltaic technologies. Multijunction cells require more elaborate and intricate characterization procedures to establish their efficiency correctly and a critical view on the results and new insights in this matter are discussed. Application of multijunction cells in photoelectrochemical water splitting and upscaling toward a commercial technology is briefly addressed.
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Semitransparent organic and perovskite solar cells are considered promising photovoltaic (PV) devices that can be applied to power-generating windows and facades of modern buildings and have achieved great progress in the past few...
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Semitransparent organic and perovskite solar cells are considered promising photovoltaic (PV) devices that can be applied to power-generating windows and facades of modern buildings and have achieved great progress in the past few years. Different from silicon-based solar cells, the optical absorption of devices with organic and perovskite active layer materials can be easily tuned by modifying the chemical structure and adjusting the halide types or contents, respectively, to meet the demands of energy-generating windows. In this review, the development progress of semitransparent PV (STPV) in terms of the selection of active layer materials, top transparent electrodes (TTEs), and strategies of enhancing the performance of STPVs is introduced. Meanwhile, the challenges and outlooks for the future development of STPVs are discussed.
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The development of organic semiconductors for photovoltaic devices, over the last three decades, has led to unexpected performance for an alternative choice of materials to convert sunlight to electricity. New materials and develo...
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The development of organic semiconductors for photovoltaic devices, over the last three decades, has led to unexpected performance for an alternative choice of materials to convert sunlight to electricity. New materials and developed concepts have improved the photovoltage in organic photovoltaic devices, where records are now found above 13% power conversion efficiency in sunlight. The author has stayed with the topic of organic materials for energy conversion and energy storage during these three decades, and makes use of the Hall of Fame now built by Advanced Materials, to present his view of the path travelled over this time, including motivations, personalities, and ambitions.
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Organic solar cells utilizing a P3HT/PCBM bilayer (BL) as their photoactive layer are fabricated using a sequential solution process. The film morphology and solar cell performance are investigated by changing the thickness of PCB...
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Organic solar cells utilizing a P3HT/PCBM bilayer (BL) as their photoactive layer are fabricated using a sequential solution process. The film morphology and solar cell performance are investigated by changing the thickness of PCBM layer. The power conversion efficiency (PEC) of a BL solar cell strongly depends on the thickness of the PCBM layer; this value increases significantly after thermal annealing above the glass transition temperature of the P3HT. Based on the water contact angle and photoluminescence (PL) measurements, most of the PCBM was diffused into the amorphous P3HT region after thermal annealing. The external quantum efficiency spectrum reveals that the morphology of the P3HT in the BL solar cell is crystalline, even without thermal annealing, in contrast to the bulk heterojunction films. Moreover, thermal annealing improves charge collection efficiency by generating crystalline P3HT and PCBM domains. The transient photovoltage experiments suggest that the morphology of P3HT and PCBM in the BL solar cell reduces the charge recombination better than that in the BHJ solar cell. The BL solar cell exhibits a PEC of 3.54%, similar to that of the BHJ solar cell.
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Spray coating is a high throughput coating technique that is scalable and adaptable for organic photovoltaic manufacturing. To ensure uniform coating of the organic layers, the wettability, surface tension and boiling points of th...
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Spray coating is a high throughput coating technique that is scalable and adaptable for organic photovoltaic manufacturing. To ensure uniform coating of the organic layers, the wettability, surface tension and boiling points of the solvents have to be optimized. Here, we used microscopic videos to understand the dynamics of the spray coating process. By optimizing the wettability and drying time of the PEDOT:PSS suspension on a hydrophobic surface, we attained a spray coated transparent anode without compromising on device performance. We further applied this vacuum-free process to a near infrared absorber to achieve a transparent organic solar cell with close to 60% transparency.
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Ternary strategies show over 16% efficiencies with increased current/voltage owing to complementary absorption/aligned energy level contributions. However, poor understanding of how the guest components tune the active layer struc...
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Ternary strategies show over 16% efficiencies with increased current/voltage owing to complementary absorption/aligned energy level contributions. However, poor understanding of how the guest components tune the active layer structures still makes rational selection of material systems challenging. In this study, two phthalimide based ultrawide bandgap polymer donor guests are synthesized. Parallel energies between the highest occupied molecular orbitals of host and guest polymers are achieved via incorporating selnophene on the guest polymer. Solid-state(19)F magic angle spinning nuclear magnetic spectroscopy, graze-incidence wide-angle X-ray diffraction, elemental transmission electron microscopy mapping, and transient absorption spectroscopy are combined to characterize the active layer structures. Formation of the individual guest phases selectively improves the structural order of donor and acceptor phase. The increased electron mobility in combination with the presence of the additional paths made by the guest not only minimizes the influence on charge generation and transport of the host system but also contributes to increasing the overall current generation. Therefore, phthalimide based polymers can be potential candidates that enable the simultaneous increase of open-circuit voltage and short-circuit current-density via fine-tuning energy levels and the formation of additional paths for enhancing current generation in parallel-like multicomponent organic solar cells.
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