Precisely Regulating Intermolecular Interactions and Molecular Packing of Nonfused-Ring Electron Acceptors via Halogen Transposition for High-Performance Organic Solar Cells.

The structure of molecular aggregates is crucial for charge transport and photovoltaic performance in organic solar cells (OSCs). Herein, the intermolecular interactions and aggregated structures of nonfused-ring electron acceptors (NFREAs) are precisely regulated through a halogen transposition strategy, resulting in a noteworthy transformation from a 2D-layered structure to a 3D-interconnected packing network. Based on the 3D electron transport pathway, the binary and ternary devices deliver outstanding power conversion efficiencies (PCEs) of 17.

Precisely Manipulating Molecular Packing via Tuning Alkyl Side-Chain Topology Enabling High-Performance Nonfused-Ring Electron Acceptors.

In the development of high-performance organic solar cells (OSCs), the self-organization of organic semiconductors plays a crucial role. This study focuses on the precisely manipulation of molecular assemble via tuning alkyl side-chain topology in a series of low-cost nonfused-ring electron acceptors (NFREAs). Among the three NFREAs investigated, DPA-4, which possesses an asymmetric alkyl side-chain length, exhibits a tight packing in the crystal and high crystallinity in the film, contributing to improved electron mobility and favorable film morphology for DPA-4.

Precise Methylation Yields Acceptor with Hydrogen-Bonding Network for High-Efficiency and Thermally Stable Polymer Solar Cells.

Utilizing intermolecular hydrogen-bonding interactions stands for an effective approach in advancing the efficiency and stability of small-molecule acceptors (SMAs) for polymer solar cells. Herein, we synthesized three SMAs (Qo1, Qo2, and Qo3) using indeno[1,2-b]quinoxalin-11-one (Qox) as the electron-deficient group, with the incorporation of a methylation strategy. Through crystallographic analysis, it is observed that two Qox-based methylated acceptors (Qo2 and Qo3) exhibit multiple hydrogen bond-assisted 3D network transport structures, in contrast to the 2D transport structure observed in gem-dichlorinated counterpart (Qo4).

Improving the Performance of Layer-by-Layer Organic Solar Cells by n-Doping of the Acceptor Layer.

Molecular dopants can effectively improve the performance of organic solar cells (OSCs). Here, PM6/BTP-eC9-4Cl-based OSCs are fabricated by a layer-by-layer (LbL) deposition method, and the electron acceptor BTP-eC9-4Cl layer is properly doped by n-type dopant benzyl viologen (BV) or [4-(1,3-dimethyl-2,3-dihydro-1-benzoimidazol-2-yl)phenyl]dimethyl-amine (N-DMBI-H). The power conversion efficiency (PCE) of OSCs increases from 16.

High-Performance Organic Solar Cells Containing Pyrido[2,3-b]quinoxaline-Core-Based Small-Molecule Acceptors with Optimized Orbit Overlap Lengths and Molecular Packing.

The central core in A-DA D-A-type small-molecule acceptor (SMAs) plays an important role in determining the efficiency of organic solar cells (OSCs), while the principles governing the efficient design of SMAs remain elusive. Herein, we developed a series of SMAs with pyrido[2,3-b]quinoxaline (PyQx) as new electron-deficient unit by combining with the cascade-chlorination strategy, namely Py1, Py2, Py3, Py4 and Py5. The introduction of chlorine atoms reduces the intramolecular charge transfer effects but elevates the LUMO values.

Improving the Performance of Layer-by-Layer Processed Organic Solar Cells via Introducing a Wide-Bandgap Dopant into the Upper Acceptor Layer.

The layer-by-layer (LbL) solution-processed organic solar cells (OSCs) are conductive to achieve vertical phase separation, tunable donor-acceptor (D/A) interfaces, and favorable charge-transport pathways. In this work, a wide-bandgap component poly(9-vinylcarbazole) (PVK) is added to the upper electron acceptor layer to improve the performance of LbL-processed OSCs. Results show that the PVK component can adjust the film morphology, dope the electron acceptor, increase the electron concentration, and improve charge transport.

Effect of Steric Hindrance at the Anthracene Core on the Photovoltaic Performance of Simple Nonfused Ring Electron Acceptors.

Solving the contradiction between good solubility and dense packing is a challenge in designing high-performance nonfullerene acceptors. Herein, two simple nonfused ring electron acceptors ( and ) carrying - or -substituted hexyloxy side chains can be facilely synthesized in only three steps. The two -substituted phenyl side chains in cannot freely rotate due to a big steric hindrance, which endows the acceptor with good solubility.

High-Performance Nonfused Ring Electron Acceptors with V-Shaped Side Chains.

Motivated by simplifying the synthesis of nonfullerene acceptor and establishing the relation between molecular structure and photovoltaic performance, two isomeric nonfused ring electron acceptors (o-TT-Cl and m-TT-Cl), whose properties can be adjusted by changing the side chains, are designed and synthesized with several high-yield steps. o-TT-Cl with V-shaped side chain induces a dominated J-aggregation and displays much better solubility and more ordered packing than m-TT-Cl with linear side chain. Thus, the o-TT-Cl-based blend film generates better phase morphology and charge transport than m-TT-Cl-based one.

Designing High-Performance Nonfused Ring Electron Acceptors Synergistically Adjusting Side Chains and Electron-Withdrawing End-Groups.

Three nonfused ring electron acceptors, , , and , are designed and synthesized. Unlike , with two sterically hindered 2,4,6-triisopropyl-phenyl groups is highly soluble, which provides a good opportunity for solution processability. Compared with , with fluorinated end-groups exhibits red-shifted absorption.

High-Performance Simple Nonfused Ring Electron Acceptors with Diphenylamino Flanking Groups.

Four simple nonfused ring electron acceptors (, , , and ) were designed and synthesized. The use of diphenylamine derivatives as the flanking group for the construction of nonfused ring electron acceptors can improve solubility, avoid the formation of oversized aggregates, and enhance the intramolecular charge-transfer effect to extend absorption spectra. The substituent group at the diphenylamine unit has a great impact on the absorption and energy level of acceptors, electron mobility and morphology of blend films.

Enhancing the Photovoltaic Performance of a Benzo[][1,2,5]thiadiazole-Based Polymer Donor via a Non-Fullerene Acceptor Pairing Strategy.

As a well-known electron-withdrawing group, benzo[][1,2,5]thiadiazole (BT) has been intensively studied and adopted to construct polymer donors with tunable band gaps. However, polymer solar cells (PSCs) with BT-based polymer donors, limited by the weak absorption and inflexible energy level of fullerene derivatives, usually suffer mediocre power conversion efficiencies (PCEs). Here, through subtly tailoring a BT unit with asymmetric fluoro and alkyloxy groups and judiciously pairing a BT-based polymer donor with three narrow band gap non-fullerene acceptors (e.

PDI-Based Hexapod-Shaped Nonfullerene Acceptors for the High-Performance As-Cast Organic Solar Cells.

Three hexapod-shaped PDI-hexamers (PSM1, PSM2, and PSM3) with a diphenylmethylene-bridged triphenylamine (TPA) core and six peripheral PDI subunits have been designed and synthesized. The influence of different peripheral PDI subunits on the morphology and crystallinity of acceptors is investigated. Distinctly different from the previously reported PDI trimers with a TPA core, which exhibit amorphous morphologies, these hexapod-shaped acceptors display improved crystallinities and photophysical properties.

Efficient Ternary Organic Solar Cells with a New Electron Acceptor Based on 3,4-(2,2-Dihexylpropylenedioxy)thiophene.

In this work, a ternary blend strategy based on PBDB-T and two small molecular acceptors (IDTT-OB and ) is demonstrated to simultaneously improve the photocurrent and reduce the voltage loss in organic solar cells (OSCs). The improved photocurrent is partially due to a broad absorption spectrum of the active layer. In addition, we find that the ternary system possesses a higher degree of crystallinity, smaller domain size, higher domain purity, and higher and more balanced charge-carrier mobilities in comparison with the two corresponding binary systems.

Noncovalently fused-ring electron acceptors with near-infrared absorption for high-performance organic solar cells.

Non-fullerene fused-ring electron acceptors boost the power conversion efficiency of organic solar cells, but they suffer from high synthetic cost and low yield. Here, we show a series of low-cost noncovalently fused-ring electron acceptors, which consist of a ladder-like core locked by noncovalent sulfur-oxygen interactions and flanked by two dicyanoindanone electron-withdrawing groups. Compared with that of similar but unfused acceptor, the presence of ladder-like structure markedly broadens the absorption to the near-infrared region.

Fluoro-Modulated Molecular Geometry in Diketopyrrolopyrrole-Based Low-Bandgap Copolymers for Tuning the Photovoltaic Performance.

Fluorination of conjugated polymers is an effective strategy to tune the energy levels for obtaining high power conversion efficiency (PCE) in organic solar cells. In this work, we have developed fluoro-modulated molecular geometries in diketopyrrolopyrrole based low-bandgap copolymers. In these polymers, planar conformation can be locked by intramolecular non-covalent interaction (intramolecular supramolecular interaction) between the sulfur atoms and the introduced F atoms (F···S interaction).

Impact of the Bonding Sites at the Inner or Outer π-Bridged Positions for Non-Fullerene Acceptors.

Two A-π-D-π-A-type non-fullerene acceptors (IDT-TFIC and IDT-TFIC) with 5-hexylthienyl chains substituted at the inner and outer β-positions of the thiophene π-bridge have been designed, respectively. Impacts of varied positional modifications are systematically studied. By utilizing PBDB-T as the donor, polymer solar cells are constructed with these two molecules as acceptors.

Controlling Molecular Packing and Orientation via Constructing a Ladder-Type Electron Acceptor with Asymmetric Substituents for Thick-Film Nonfullerene Solar Cells.

A nonfullerene acceptor, IDTT-OB, employing indacenodithieno[3,2- b]thiophene (IDTT) decorated with asymmetric substituents as the core, is designedly prepared. In comparison with the analogue IDT-OB, extending the five-heterocyclic indacenodithiophene (IDT) core to seven-heterocyclic fused ring endows IDTT-OB with more broad absorption and elevated highest occupied molecular orbital energy level. In addition, IDTT-OB shows a more intense molecular packing and a higher crystalline behavior with a strong face-on orientation in the neat film and the PBDB-T:IDTT-OB blend film.

Fused-Ring Acceptors with Asymmetric Side Chains for High-Performance Thick-Film Organic Solar Cells.

A kind of new fused-ring electron acceptor, IDT-OB, bearing asymmetric side chains, is synthesized for high-efficiency thick-film organic solar cells. The introduction of asymmetric side chains can increase the solubility of acceptor molecules, enable the acceptor molecules to pack closely in a dislocated way, and form favorable phase separation when blended with PBDB-T. As expected, PBDB-T:IDT-OB-based devices exhibit high and balanced hole and electron mobility and give a high power conversion efficiency (PCE) of 10.

Effect of Non-fullerene Acceptors' Side Chains on the Morphology and Photovoltaic Performance of Organic Solar Cells.

Three indacenodithieno[3,2-b]thiophene (IT) cored small molecular acceptors (ITIC-SC6, ITIC-SC8, and ITIC-SC2C6) were synthesized, and the influence of side chains on their performances in solar cells was systematically probed. Our investigations have demonstrated the variation of side chains greatly affects the charge dissociation, charge mobility, and morphology of the donor:acceptor blend films. ITIC-SC2C6 with four branched side chains showed improved solubility, which can ensure the polymer donor to form favorable fibrous nanostructure during the drying of the blend film.

A simplified PCR-SSP method for HLA-A2 subtype in a population of Wuhan, China.

HLA-A2 is the most frequent HLA-A allele in all ethnic populations, and an important restriction element for peptide presentation to T cells in infectious disease and cancer. However, the HLA-A2 supertype consisting of up to 75 subtypes, mutation studies and analyses using cytotoxic T lymphocytes suggest the functional relevance of subtype-specific differences in HLA-A2 molecules for peptide binding and T-cell recognition. Therefore, it is necessary for T-cell response study to discriminate the HLA-A2 subtypes and to understand the profile of HLA-A2 allelic distribution in a given population.

Induction of the Epstein-Barr virus latent membrane protein 2 antigen-specific cytotoxic T lymphocytes using human leukocyte antigen tetramer-based artificial antigen-presenting cells.

Cytotoxic T lymphocytes (CTLs) specific for the Epstein-Barr virus (EBV) latent membrane protein 2 (LMP2) antigen are important reagents for the treatment of some EBV-associated malignancies, such as EBV-positive Hodgkin's disease and nasopharyngeal carcinoma. However, the therapeutic amount of CTLs is often hampered by the limited supply of antigen-presenting cells. To address this issue, an artificial antigen-presenting cell (aAPC) was made by coating a human leukocyte antigen (HLA)-pLMP2 tetrameric complex, anti-CD28 antibody and CD54 molecule to a cell-sized latex bead, which provided the dual signals required for T cell activation.

[HLA-G1 molecule expressed by ECV304 cells inhibit cytotoxic activity of allogeneic NK cells].

Aim: To study the effect of HLA-G1 molecule expressed by an endothelial cell line (ECV304) on the cytotoxic activity of allogeneic NK cells.

Methods: ECV304 cells were transfected with recombinant plasmid pcDNA3-HLA-G1 by the liposome transfection, and the expressed HLA-G1 on the cell surface was detected by indirect immunofluorescent assay and flow cytometry. The cytotoxic activity of allogeneic NK cells against ECV304 cells was analyzed by the MTT method.