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Size Effect of Two Dimension Conjugated Space in Photovoltaic Polymersa?? Side-chain: Balancing Phase Separation and Charge Transport
摘要： Various two-dimension (2D) side-chains substituted benzo(1,2-b:4,5-b’)dithiophene (BDT) blocks have been used to construct donor polymers, while the size effect of side-chains on photovoltaic performance was overlooked in past few years. This work, three size varied conjugated space (benzene, naphthalene and biphenyl) were introduced into corresponding polymers PBDB-Ph, PBDB-Na and PBDB-BPh. This space engineering has significant impact on the extent of phase separation in active layer which blended with polymer and acceptor ITCPTC and preserved the desired morphology. Varied space size in side-chains lead to distinct balance mobility ratios of hole to electron (benzene is 0.21, and for naphthalene is 0.75, biphenyl is 0.57). Finally, PBDB-Na-based polymer solar cells (PSCs) delivered the highest power conversion efficiency (PCE) 12.52% when compared to the PSCs performance of PBDB-Ph (8.48%) and PBDB-BPh (11.35%). The mothed in tailoring the side-chains structures could fabricate a balance between phase separation and charge transport, providing an enlightenment for the development of photovoltaic device.
关键词： side-chain,phase separation,desired morphology,charge transport,photovoltaic performance
更新于2025-09-16 10:30:52
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Benzodithiophenedione-based polymers: recent advances in organic photovoltaics
摘要： Over the past 20 years, significant progress has been made in organic photovoltaics (OPVs) due to its advantages of being cost-effective, being lightweight, and having flexible manufacturability. The optical-active layer of OPVs consists of a p-type polymer as the donor and an n-type small molecule as the acceptor. An efficient design strategy of a polymer donor is based on an alternating electron-donating unit (D) and an electron-accepting unit (A). Among numerous electron-accepting units, an emerging annelated thiophene of benzodithiophenedione (BDD) has exhibited a distinguished photovoltaic performance because of its planar molecular structure, low-lying highest occupied molecular orbit (HOMO) level and good self-assembly property. In this review article, we summarize the most recent developments in BDD-based photovoltaic materials. Special attention is paid to the chemical structure-property relationships, such as the absorption, bandgap, energy levels, mobilities, and photovoltaic performances. The empirical regularities and perspectives on the future development of BDD-based photovoltaic materials are included.
关键词： chemical structure-property relationships,benzodithiophenedione,photovoltaic performance,polymer donors,organic photovoltaics
更新于2025-09-16 10:30:52
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Synergistic effect of processing solvent and additive for the production of efficient all-polymer solar cells
摘要： Ideal morphological features are of particular importance to produce high performance all-polymer solar cells (all-PSCs), in which the active blends generally involve unfavorable phase separation due to the complicated intermixing. Developing suitable processing solvent and additive is an effective and versatile approach to manipulate the blends morphology. This study demonstrates the synergistic effect of processing solvent and additive to the photovoltaic performances of all-PSCs composed of a conjugated copolymer J71 donor and typical N2200 acceptor. The low boiling point chloroform (CF) solvent combined with 1% 1,8-diiodoctane (DIO) additive was identified as the optimal processing condition to treat the J71:N2200 blends. Consequently, the all-PSCs casting from CF + 1% DIO achieved an outstanding efficiency of 9.34% with an ultrahigh fill factor of 77.86%, which is among the top values for current all-PSCs systems. Owing to the low JSC, just a moderate efficiency of 7.28% was obtained for the device from chlorobenzene (CB) + 1% DIO processing despite of its high FF. The electron microscopic tests revealed that the CF was superior to CB solvent to obtain uniform morphologies and the addition of DIO additive could further generate more favorable phase separation and domain size. Moreover, the results of charge generation, transport, and recombination analysis correlate well with the remarkable photovoltaic properties. Our results highlight the critical significance of selecting appropriate processing solvent and additive to pursue high performing all-PSCs.
关键词： all-polymer solar cells,processing solvent,morphology,additive,photovoltaic performance
更新于2025-09-16 10:30:52
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Modulation of Building Block Size in Conjugated Polymers with D–A Structure for Polymer Solar Cells
摘要： D?A conjugated polymers have played critical roles in recently reported nonfullerene acceptors-based polymer solar cells (NF-PSCs) with high performance. Although the molecular design of the D?A polymers is getting more mature, there are still some fundamental unknowns to be unveiled. Here, three new D?A polymers with varied conjugated length for the D-units in their backbones, namely, PDB-1, PDB-2, and PDB-3, were designed, synthesized, and characterized. It was demonstrated that a longer D-unit leads to stronger interchain interaction and higher hole mobility for pristine polymer films. While blending with IT-4F to fabricate photoactive layers in PSCs, it was found that the domain purity, aggregation size, and π?π stacking effect of the polymers can be greatly affected by the D-unit size. Compared to polymers with shorter D-units, for the polymer with the largest D-units (PDB-3), hole and electron transport channels can be much more easily formed in the blend films. Interestingly, the highest efficiency was obtained in the PSCs based on a PDB-2:IT-4F blend, in which PDB-2 shows similar D-unit size to the polymers with state-of-the-art high photovoltaic performance. The correlations between the molecular structure and photovoltaic property of PDB-x polymers demonstrate that the modulation of building block size is an important method for designing high-performance D?A conjugated polymers for PSCs.
关键词： polymer solar cells,nonfullerene acceptors,D?A conjugated polymers,building block size,photovoltaic performance
更新于2025-09-16 10:30:52
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Influence of single-walled carbon nanotubes induced exciton dissociation improvement on hybrid organic photovoltaic devices
摘要： Torch-plasma-grown single-walled carbon nanotubes (SWCNTs) are integrated with regioregular poly(3-hexylthiophene) (P3HT) and a fullerene derivative 1-(3-methoxycarbonyl) propyl-1-phenyl[6,6]C61 (PCBM) as a hybrid photoactive layer for bulk heterojunction solar cell devices. We demonstrate that molecular information could be accurately obtained by time-of-flight secondary ion mass spectrometry through the hybrid organic photoactive solar cell layers when sputtering is performed using a Cs+ 2000 eV ion source. Furthermore, the photovoltaic (PV) performance of the fabricated devices show an increase in the short-circuit current density (Jsc) and the fill factor (FF) as compared to the pristine devices fabricated without SWCNTs. The best results are obtained with 0.5 wt. % SWCNT loads, where an open-circuit voltage (VOC) of 660 mV is achieved, with a Jsc of 9.95 mA cm?2 and a FF of 54%, leading to a power conversion efficiency of 3.54% (measured at standard test conditions, AM1.5 g). At this optimum SWCNT concentration of 0.5 wt. %, and to further understand the charge-transfer mechanisms taking place at the interfaces of P3HT:PCBM:SWCNT, Jsc is measured with respect to the light intensity and shows a linear dependency (in the double logarithmic scale), which implies that losses in the charge carrier are rather governed by monomolecular recombination. Finally, our results show that our hybrid devices benefit from the fullerene electron accepting nature and from the SWCNT fast electron transportation feature that improve substantially the exciton dissociation efficiency. The influence of the SWCNTs on the Fermi level and the work function of the photoactive composite and its impact on the PV performance is also investigated.
关键词： single-walled carbon nanotubes,bulk heterojunction,PCBM,hybrid organic photovoltaic devices,photovoltaic performance,P3HT,exciton dissociation
更新于2025-09-12 10:27:22
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Polyfluorene Copolymers as High‐Performance Hole Transport Materials for Inverted Perovskite Solar Cells
摘要： Inverted perovskite solar cells (PSCs) that can be entirely processed at low temperatures have attracted growing attention owing to their cost-effective production. Hole-transport materials (HTMs) play an essential role in achieving efficient inverted PSCs, as they determine the effectiveness of charge extraction and recombination at interfaces. In this study, three polyfluorene copolymers (TFB, PFB and PFO) were investigated as HTMs for construction of inverted PSCs. It is found that the photovoltaic performance of the solar cells is closely correlated with the electronic properties of the HTMs. Owing to its high mobility along with the favored energy level alignment with perovskite, TFB showed superior charge extraction and suppressed interfacial recombination than PFB- and PFO-based devices, which delivers a high efficiency of 18.48% with an open-circuit voltage (VOC) of up to 1.1 V. In contrast, the presence of a large energy barrier in the PFO-based devices resulted in substantial losses in both VOC and photocurrent. These results demonstrate that TFB could serve as a superior HTM for inverted PSCs. Moreover, we anticipate that the performance of the three HTMs identified here might guide molecular design of novel HTMs for the manufacture of highly efficient inverted PSCs.
关键词： hole-transport materials,charge extraction,polyfluorene copolymers,photovoltaic performance,inverted perovskite solar cells
更新于2025-09-12 10:27:22
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Highly Crystallized C-Doped Nickel Oxide Nanoparticles for p-Type Dye-Sensitized Solar Cells with Record Open-Circuit Voltage Breaking 0.5 V
摘要： In this work, unique carbon-doped NiO nanostructure (denoted as C/NiO) was synthesized via a facile precipitation/reduction reaction, followed by a subsequent oxidation process. The successful introduction of carbon in NiO gave rise to multiple tailing of the physical and electronic characteristics, including morphology, crystallinity, and conductivity, and valence band edge position. The carbon-doped NiO-fabricated dye sensitized solar cells actively generated an unrivalled VOC of 0.50 V and also a significantly increased short-circuit current densities (JSC, 0.202 mA cm-2), leading to an overall efficiency of 0.053%. The improved of photovoltaic performance could be mainly attributed to the significantly enhanced charge transport property and regarded charge recombination occurred at the NiO/electrolyte interface. This work provides an extremely simple and effective strategy for incorporating nonmetal elements in semiconductor oxides with remarkably improved photovoltaic performance.
关键词： charge transport,carbon-doped NiO,dye-sensitized solar cells,photovoltaic performance,valence band edge
更新于2025-09-12 10:27:22
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Nonhalogenated-Solvent-Processed Efficient Polymer Solar Cells Enabled by Medium-Band-Gap A?π–D?π–A Small-Molecule Acceptors Based on a 6,12-Dihydro-diindolo[1,2- <i>b</i> :10,20- <i>e</i> ]pyrazine Unit
摘要： In this contribution, a series of A?π?D?π?A small molecules (SMs), IPY-T-IC, IPY-T-ICCl, and IPY-T-ICF, containing the central donor unit (D) of 6,12-dihydro-diindolo[1,2-b:10,20-e]pyrazine (IPY), the π-conjugated bridge of thiophene, and the end-accepting group (A) of 3-(dicyanomethylidene)indol-1-one, 5,6-dichloro-3-(dicyanomethylidene)indol-1-one, or 5,6-difluoro-3-(dicyanomethylene)indol-1-one, were developed, characterized, and employed as the acceptor materials for polymer solar cells (PSCs). Influences of the different end-accepting groups on thermal properties, spectral absorption, energy levels, photovoltaic performance, and film morphology of these small-molecule acceptors (SMAs) were investigated in detail. These SMAs exhibit an excellent thermal stability and strong crystallization. The absorption spectra of these SMs mainly locate the wavelength between 400 and 700 nm, associated with the optical band gaps in the range of 1.75?1.90 eV. Compared with nonhalogenated IPY-T-IC, the halogenated SMAs IPY-T-ICCl and IPY-T-ICF present better absorption abilities, wider absorption region, and downshifted highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) levels. With regard to the complementary spectral absorption and matched HOMO/LUMO levels, PTB7-Th as a low-band gap polymer was chosen to be an electron donor to pair with these SMAs for fabricating bulk-heterojuntion PSCs. Under optimized conditions, among these SMAs, the PTB7-Th:IPY-T-IC-based PSC processed from a halogenated solvent system (chlorobenzene + 1-chloronaphthalene) delivers the best power conversion efficiency (PCE) of 7.32%, mainly because of more complementary spectral absorption, upper-lying LUMO level, higher and balanced carrier mobility, more efficiently suppressed trap-assisted recombination, better charge collection property, and blend morphology. Encouragingly, an improved PCE of up to 7.68% is achieved when the IPY-T-IC-based solar cell was processed from a nonhalogenated solvent system (o-xylene + 2-methylnaphthalene). In view of the large band gap of these IPY-based SMAs, the PCE of over 7.5% is notable and attractive for the related community. Our study argues that the IPY moiety is a potential electron-donating building moiety to develop medium-band-gap high-performance A?π?D?π?A SMAs for nonhalogenated-solvent-processed photovoltaic devices.
关键词： A?π?D?π?A,polymer solar cells,small-molecule acceptors,6,12-dihydro-diindolo[1,2-b:10,20-e]pyrazine,photovoltaic performance
更新于2025-09-12 10:27:22
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Naphthalene core-based noncovalently fused-ring electron acceptors: effects of linkage positions on photovoltaic performances
摘要： Two mutually isomeric noncovalently fused-ring electron acceptors (NC-FREAs) NOC6F-1 and NOC6F-2 containing two cyclopentadithiophene (CPDT) moieties linked at the 2,6- and 1,5-positions, respectively, of the naphthalene ring were designed and synthesized for organic solar cells (OSCs). Intramolecular noncovalent S···O interactions were introduced into NOC6F-1 and NOC6F-2. The tiny structural variation in NOC6F-1 and NOC6F-2 by just changing the linkage positions affects largely their molecular configuration, absorption, molecular packing, charge transport and photovoltaic performance. Compared to NOC6F-2, NOC6F-1 exhibits smaller distortions between cyclopentadithiophene and the naphthalene unit, leading to an extended conjugation and enhanced p–p stacking. NOC6F-2 exhibits a poor planarity, which restricts the electron delocalization as well as dense p–p stacking in the film form. When blended with PBDB-T, NOC6F-1 exhibits more orderly stacking along both the out-of-plane and in-plane directions than NOC6F-2. OSCs based on PBDB-T:NOC6F-2 merely showed a power conversion efficiency (PCE) of 6.74% with lower Jsc and FF values. OSCs based on NOC6F-1 achieved a higher Jsc of 17.08 mA cm?2 and an FF of 65.79%, thus leading to a significantly enhanced PCE of 10.62%. These results indicate that use of the acceptor molecules with a planar molecular backbone is an important design strategy for NC-FREAs.
关键词： noncovalently fused-ring electron acceptors,charge transport,organic solar cells,photovoltaic performance,molecular configuration
更新于2025-09-12 10:27:22
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Performance evaluation and economical analysis of three photovoltaic systems installed in an institutional building in Errachidia, Morocco
摘要： A study was conducted in order to evaluate the performance and the Economic analysis of three photovoltaic system connected to the grid (5.94 kWp) in Errachidia city in Morocco. Several parameters of the PV systems design were evaluated such as: the total energy generated, final yield, reference yield, performance ratio, capacity factor and monthly system efficiency. The economic input of the three systems was determined based on economic return of electricity generation. The highest values in terms of daily final yield (YF = 5.26 h/day), performance ratio (PR = 82 %), capacity factor (CF = 21.93 %), levelized cost of electricity (LCOE = 0.068 €/kWh) and payback time (PB = 12), were recorded by pc-Si solar module. Therefore, this PV system technology could be recommended in the future research projects in Morocco.
关键词： economic analysis,final yield,capacity factor,photovoltaic,performance ratio,grid connected,LCOE
更新于2025-09-12 10:27:22