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Higha??Performance Nonfullerene Organic Solar Cells with Unusual Inverted Structure
摘要： A new fused-ring electron acceptor FOIC1 was designed and synthesized. FOIC1 exhibits intense absorption in the range of 600-1000 nm, HOMO/LUMO energy levels of –5.39/–3.99 eV, and electron mobility of 1.8 × 10–3 cm2 V–1 s–1. Organic solar cells based on sequentially processed heterojunction (SHJ) with unusual inverted structure were fabricated. Through sequentially spin-coating polymer donor PTB7-Th as the bottom layer and acceptor FOIC1 as the top layer, a better vertical phase distribution is formed in this SHJ compared with that in traditional bulk heterojunction (BHJ). In the upper-half part, a more balanced donor/acceptor distribution is beneficial for exciton dissociation. At the bottom interface, more FOIC1 accumulation is beneficial for exciton generation and charge transport. Overall, the SHJ cells exhibit power conversion efficiency as high as 12.0%, higher than that of the BHJ counterpart (11.0%).
关键词： sequential processing,inverted structure,nonfullerene,fused-ring electron acceptor,organic solar cell
更新于2025-09-23 15:21:01
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An inverted BiI3/PCBM binary quasi-bulk heterojunction solar cell with a power conversion efficiency of 1.50%
摘要： The use of toxic Pb hinders the widespread applications of lead halide perovskite solar cells, sparking an upsurge effort to develop lead-free solar cells. This work reports a facile low-temperature solution processed bismuth triiodide (BiI3)/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) binary quasi-bulk heterojunction (BQ-BH) solar cell. The BiI3 and PCBM layers are innovatively utilized as the electron donor and acceptor to form a BQ-BH that promotes the separation of the excitons. The effective separation of excitons at the BiI3/PCBM BQ-BH is experimentally confirmed by the Kelvin probe force microscopy. An optimized inverted BiI3/PCBM BQ-BH solar cell can achieve a champion power conversion efficiency of 1.50% with a record short-circuit current density of 8.76 mA cm-2. The findings of this work confirm that the separation of excitons can be effectively promoted by inducing a suitable electron donor/acceptor type of BQ-BH, providing a new means to enhance the performance of BiI3-based solar cells.
关键词： electron acceptor,quasi-bulk heterojunction,exciton separation,solar cells,BiI3
更新于2025-09-23 15:21:01
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Achieving efficient green-solvent-processed organic solar cells by employing ortho-ortho perylene diimide dimer
摘要： The lack of electron acceptors with suitable green solvent processing and excellent device performance is an important problem that hinders the development and commercialization of organic solar cells (OSCs). Here, an ortho-ortho perylene diimide (PDI) dimer (oo-2PDI) is developed and used as an acceptor for use in efficient green-solvent-processed (GSP) OSCs. By using chlorobenzene (CB), anisole, and ortho-xylene as the processing solvents, power conversion efficiencies (PCEs) of 5.04%, 5.03%, and 5.78% were achieved without the additive, respectively. In addition, the non-fullerene oo-2PDI-based GSPOSCs show superior photovoltaic performance to [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)-based GSPOSCs under identical conditions. Therefore, these results demonstrate the possibility of achieving efficient non-fullerene GSPOSCs.
关键词： Electron acceptor,Perylene diimide,Green solvent,Ortho-ortho dimer,Organic solar cell
更新于2025-09-23 15:21:01
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Near-Infrared Electron Acceptors with Unfused Architecture for Efficient Organic Solar Cells
摘要： Nonfullerene acceptor (NFA) with near-infrared (NIR) region absorption is crucial for obtaining high current densities in organic solar cells (OSCs). Herein, two narrow bandgap NFAs with unfused backbones possessing broad (600-900 nm) and strong absorption are developed by the conjugation of a benzothiadiazole (BT) core to halogenated end-groups through cyclopentadithiophene (CPDT) bridge. Compared with the fluorinated counterpart BCDT-4F, the chlorinated NFA BCDT-4Cl appears stronger J-aggregation and closer molecular packing, leading to the optimized blend morphology when paired with polymer donor, PBDB-T. Thus, an obvious improvement of external quantum efficiency response was obtained for BCDT-4Cl based OSCs, presenting a higher efficiency of 12.10% than that (9.65%) based on BCDT-4F. This work provides a design strategy for NIR acceptors in the combination of electron deficient core and halogenated terminal in unfused backbone, which results in not only fine-tuning of optoelectronic properties, but also the simplified synthetic complexities of molecule.
关键词： electron-deficient core,organic solar cell,halogenated end-group,unfused architecture,near-infrared electron acceptor
更新于2025-09-23 15:19:57
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Novel Heteroleptic Ruthenium(II) Complexes with 2,2a?2- Bipyridines Containing a Series of Electron-Donor and Electron-Acceptor Substituents in 4,4a?2-Positions: Syntheses, Characterization, and Application as Sensitizers for ZnO Nanowire-Based Solar Cells
摘要： A novel series of complexes of the formula [Ru(4,4′-X2-bpy)2(Mebpy-CN)](PF6)2 (X = ?CH3, ?OCH3, ?N(CH3)2; Mebpy-CN = 4-methyl-2,2′-bipyridine-4′-carbonitrile) have been synthesized and characterized by spectroscopic, electrochemical, and photophysical techniques. Inclusion of the electron-withdrawing substituent ?CN at one bpy ligand and di?erent electron-donor groups ?X at the 4,4′-positions of the other two bpy ligands produce a ?ne tuning of physicochemical properties. Redox potentials, electronic absorption maxima, and emission maxima correlate well with Hammett’s σ p parameters of X. Quantum mechanical calculations are consistent with experimental data. All the complexes can be anchored through the nitrile moiety of Mebpy-CN over ZnO nanowires in dye-sensitized solar cells that exhibit an improvement of light to electrical energy conversion e?ciency as the electronic asymmetry increases in the series.
关键词： Electron-donor and Electron-acceptor substituents,Ruthenium(II) complexes,ZnO nanowire-based solar cells,Dye-sensitized solar cells,2,2′-Bipyridines
更新于2025-09-23 15:19:57
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A 3D nonfullerene electron acceptor with a 9,9a?2-bicarbazole backbone for high-efficiency organic solar cells
摘要： One-dimensional ladder-type nonfullerene electron acceptors (NFAs) with large fused ring cores have been widely used in highly efficient organic solar cells (OSCs). Recent studies have demonstrated that small molecule acceptors with three-dimensional (3D) structures may exhibit low energy loss, and hence can lead to improved OSC performance. In this study, a new 3D NFA (99CZ-8F) with a 9,9'-bicarbazole backbone was designed, synthesized, and characterized, where two linear A-D-A architectures were linked by a single N-N bond. 99CZ-8F showed strong absorption in the range of 500-800 nm in the solid state, which is complementary to the absorption of the donor material PM6. After regulating the morphology of the active layer via binary solvent mixture, the optimized device exhibited a maximum power conversion efficiency (PCE) of 6.6 – 0.1 %, which is among the best reported values for 3D nonfullerene electron acceptor based OSCs.
关键词： Organic solar cells,end-capped groups,3D molecular structure,bicarbazole,nonfullerene electron acceptor
更新于2025-09-23 15:19:57
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Enhanced Efficiency and Stability of Nonfullerene Ternary Polymer Solar Cells Based on Spontaneously Assembled Active Layer: The Role of a High Mobility Small Molecular Electron Acceptor
摘要： It is challenging to afford efficient and stable organic solar cells based on the as-cast active layer without any external treatments. We present a planar organic electron acceptor BPTCN with high electron mobility as a third component in nonfullerene ternary polymer solar cells, which comprises an electron-deficient 4,7-bis(5H-4,6-dioxothieno[3,4-c]pyrrol-1-yl)benzo[c][1,2,5]thiadiazole core, doubly endcapped by 2-(3-ethyl-5-methylene-4-oxothiazolidin-2-ylidene)malononitrile through the alkylated thiophene-2,5-ylene unit. It shows a π-π stacking distance of 3.60 ? and μe of 1.31 × 10?3 cm2 V?1 s?1. BPTCN exhibits an absorption maximum at 569 nm in the as-cast film and good miscibility with the NIR-absorption acceptor COi8DFIC, leading to complete f?rster energy transfer in the blends. Adding BPTCN into the PTB7-Th:COi8DFIC blend produces multiple beneficial effects: i) facilitating exciton dissociation and charge transfer at the donor/acceptor interface while suppressing bimolecular and trap-assisted recombination by analysis of the Jph–Veff, Jsc–Ilight and Voc–Ilight characteristics, ii) increasing hole and in particular electron transport; and iii) generally promoting the crystallinity of the polymer donor PTB7-Th, as revealed by grazing incidence X-ray diffraction. Moreover, the phase purity is greatly improved in the ternary blend PTB7-Th:COi8DFIC:BPTCN (1:1.05:0.45 by weight). Consequently, the tentatively optimized ternary solar cell provides a PCE of 11.62% with Voc = 0.74 V, Jsc = 25.93 mA cm-2 and FF = 60.61% in comparison with the binary systems PTB7-Th:COi8DFIC (PCE of 9.41%) and PTB7-Th:BPTCN (6.42%) in the absence of any extra treatments. After thermal aging at 80 oC for 450 h, this ternary solar cell exhibits increased stability with PCE retaining 84.39% of the initial value.
关键词： PTB7-Th,COi8DFIC,BPTCN,electron acceptor,organic solar cells,thermal stability,nonfullerene ternary polymer solar cells
更新于2025-09-23 15:19:57
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Designing alkoxy-induced based high performance near infrared sensitive small molecule acceptors for organic solar cells
摘要： Scientist are dedicated to design and synthesize efficient photovoltaic materials to overcome the energy crises. In this regard, herein, we have designed four new small acceptor molecules namely (A1, A2, A3 and A4) for better performance in organic solar cells. These molecules consist Alkoxy-Induced Naphtho-dithiophene core unit flanked with 2,2-ethylidene-5,6-dicyano-3-oxo-2,3-dihydroinden-1-ylidene-malononitrile (A1), methyl-2-cyano-2,2-ethylidene-5,6-difluoro-3-oxo-2,3-dihydroinden-1-ylidene-acetate (A2), 5,2-ethylidene-5,6-difluoro-3-oxo-2,3-dihydroinden-1-ylidene-3-methyl-2-thioxothiazolidin-4-one (A3) and 2,5-ethylidene-6-oxo-5,6-dihydrocyclopenta-thiophen-4-ylidene-malononitrile (A4) end-capped acceptor groups. Their optical, electrical and geometries have been compared with reported molecule R. Frontier molecular orbital diagram reveal excellent charge transfer rate, The electron density is shifted from donor to acceptor unit. Among all, A1 exhibits the highest absorption in the visible region (λmax) at 798 nm in chloroform solvent. The maximum open circuit voltage (2.08 V) is observed for A3 when blended with PTB7-Th donor polymer. All studied molecules have high charge mobilities due to lower reorganization energy values with respect to model molecule R. A1 has the highest electron mobility among all molecules due to lower value of reorganization energy which is 0.0034. Furthermore, all designed molecules show good Solubilities in organic solvent. A2 exhibit high value of dipole moment which reveal good solubilities in fabrication process.
关键词： Transition density matrix,Non-fullerene acceptor,Open circuit voltages,Naphtho-dithiophene,Reorganization energy,Fused ring electron acceptor
更新于2025-09-19 17:13:59
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Synthesis of the diketopyrrolopyrrole/terpyridine substituted carbazole derivative based polythiophenes for photovoltaic cells
摘要： A series of conjugated polythiophenes (PTs) having low band gap energies (PDPP, PDPCz21, PDPCz11), with 2-ethylhexyl-functionalized 2,5-thienyl diketopyrrolopyrrole (TDPP) as the electron acceptor and terpyridine-substituted carbazole (TPCz) as the electron donor, have been synthesized and studied for their applicability in polymer-based photovoltaic cells (PVCs). The thermal stability and solvent solubility of PTs increased upon increasing the content of the TPCz derivative. PVCs were fabricated having the following architecture: indium tin oxide/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate/PT:6,6-phenyl-C71-butyric acid methyl ester (PC71BM)/Ca/Ag. The compatibility between the PT and PC71BM improved upon increasing the TPCz content. The photovoltaic properties of the PDPCz21-based PVCs were superior to those of their PDPP- and PDPCz11-based counterparts.
关键词： electron donor,photovoltaic cells,diketopyrrolopyrrole,electron acceptor,conjugated polythiophenes,terpyridine-substituted carbazole
更新于2025-09-19 17:13:59
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5H-Benzo[d]Benzo[4,5]Imidazo[2,1-b][1,3]Thiazine as a Novel Electron-Acceptor Cored High Triplet Energy Bipolar Host Material for Efficient Solution-Processable Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes
摘要： Organic entities that can transport electrons are seldom available to develop adequate bipolar host materials applicable for solution-processable thermally activated delayed ?uorescence (TADF)-organic light-emitting diodes (OLEDs). Therefore, the introduction of new electron-af?ne entities that plausibly demonstrate high triplet energy (ET) is of urgent need. In this contribution, we introduced benzimidazo[1,2-a][3,1]benzothiazine (BBIT) as a novel electron-af?ne entity and developed two new bipolar host materials, CzBBIT and 2CzBBIT. Both host materials exhibit high ET of 3.0 eV, superior thermal robustness with the thermal decomposition temperature of up to 392?C, a glass transition temperature of up to 161?C, and high solubility in common organic solvents. Consequently, the solution-processable OLEDs fabricated using a recognized IAcTr-out as the green TADF emitter doped into CzBBIT as the host, realized a maximum external quantum ef?ciency (EQE) of 23.3%, while the 2CzBBIT:IAcTr-out blend ?lm-based device displayed an EQE of 18.7%. These outcomes corroborated that this work could shed light on the scienti?c community on the design of new electron-af?ne entities to establish the effective use of bipolar host materials toward pro?cient solution-processable TADF-OLEDs.
关键词： bipolar hosts,new electron-acceptor core,thermally activated delayed ?uorescence,organic light emitting diodes,solution process
更新于2025-09-19 17:13:59