Coronary Vasospasm Presenting in a Catastrophic Way.

Coronary artery vasospasm is an under-recognized yet fatal condition that can manifest as sudden cardiac arrest. A 51-year-old man presented with out-of-hospital cardiac arrest due to ventricular fibrillation during exercise. Coronary angiogram showed severe disease at ostial left main coronary artery and left anterior descending artery (LAD), that was not present anymore on repeated angiography and intravascular ultrasound assessment.

Uncovering the out-of-plane nanomorphology of organic photovoltaic bulk heterojunction by GTSAXS.

The bulk morphology of the active layer of organic solar cells (OSCs) is known to be crucial to the device performance. The thin film device structure breaks the symmetry into the in-plane direction and out-of-plane direction with respect to the substrate, leading to an intrinsic anisotropy in the bulk morphology. However, the characterization of out-of-plane nanomorphology within the active layer remains a grand challenge.

Molecular insights of exceptionally photostable electron acceptors for organic photovoltaics.

Photo-degradation of organic semiconductors remains as an obstacle preventing their durable practice in optoelectronics. Herein, we disclose that volume-conserving photoisomerization of a unique series of acceptor-donor-acceptor (A-D-A) non-fullerene acceptors (NFAs) acts as a surrogate towards their subsequent photochemical reaction. Among A-D-A NFAs with fused, semi-fused and non-fused backbones, fully non-fused PTIC, representing one of rare existing samples, exhibits not only excellent photochemical tolerance in aerobic condition, but also efficient performance in solar cells.

Soft Porous Blade Printing of Nonfullerene Organic Solar Cells.

Developing scalable and robust processing methods with low material waste remains a challenge for organic solar cells (OSCs) to become a practical renewable energy source. Here, we present a novel low-cost processing approach termed as soft porous blade printing (SPBP), which uses a layer of soft porous material such as filter paper as the printing blade. The inherent porous microstructure of the blade offers high shear rates that facilitate the alignment, crystallization, and orientation of active materials during printing.

Asymmetric Electron Acceptors for High-Efficiency and Low-Energy-Loss Organic Photovoltaics.

Low energy loss and efficient charge separation under small driving forces are the prerequisites for realizing high power conversion efficiency (PCE) in organic photovoltaics (OPVs). Here, a new molecular design of nonfullerene acceptors (NFAs) is proposed to address above two issues simultaneously by introducing asymmetric terminals. Two NFAs, BTP-S1 and BTP-S2, are constructed by introducing halogenated indandione (A ) and 3-dicyanomethylene-1-indanone (A ) as two different conjugated terminals on the central fused core (D), wherein they share the same backbone as well-known NFA Y6, but at different terminals.

Simple non-fused electron acceptors for efficient and stable organic solar cells.

The flexibility in structural design of organic semiconductors endows organic solar cells (OSCs) not only great function-tunabilities, but also high potential toward practical application. In this work, simple non-fused-ring electron acceptors are developed through two-step synthesis from single aromatic units for constructing efficient OSCs. With the assistance of non-covalent interactions, these rotatable non-fused acceptors (in solution) allow transiting into planar and stackable conformation in condensed solid, promoting acceptors not only feasible solution-processability, but also excellent film characteristics.

Manipulating the Mixed-Perovskite Crystallization Pathway Unveiled by In Situ GIWAXS.

Mixed perovskites have achieved substantial successes in boosting solar cell efficiency, but the complicated perovskite crystal formation pathway remains mysterious. Here, the detailed crystallization process of mixed perovskites (FA MA Pb(I Br ) ) during spin-coating is revealed by in situ grazing-incidence wide-angle X-ray scattering measurements, and three phase-formation stages are identified: I) precursor solution; II) hexagonal δ-phase (2H); and III) complex phases including hexagonal polytypes (4H, 6H), MAI-PbI -DMSO intermediate phases, and perovskite α-phase. The correlated device performance and ex situ characterizations suggest the existence of an "annealing window" covering the duration of stage II.

Fused Benzothiadiazole: A Building Block for n-Type Organic Acceptor to Achieve High-Performance Organic Solar Cells.

Narrow bandgap n-type organic semiconductors (n-OS) have attracted great attention in recent years as acceptors in organic solar cells (OSCs), due to their easily tuned absorption and electronic energy levels in comparison with fullerene acceptors. Herein, a new n-OS acceptor, Y5, with an electron-deficient-core-based fused structure is designed and synthesized, which exhibits a strong absorption in the 600-900 nm region with an extinction coefficient of 1.24 × 10 cm , and an electron mobility of 2.

Crystal Engineering of Biphenylene-Containing Acenes for High-Mobility Organic Semiconductors.

Herein we report the synthesis, crystal structures, and semiconductor properties of new derivatives of bisnaphtho[2',3':3,4]cyclobut[1,2- b:1',2'- i]anthracene (BNCBA). It is found that the π-π stacking of BNCBA in single crystals can be largely modified by alkyl substituting groups of different lengths. In particular, the tetrahexyl derivative exhibits π-π stacking with an unusual zigzag arrangement.

Enhanced Charge Transfer between Fullerene and Non-Fullerene Acceptors Enables Highly Efficient Ternary Organic Solar Cells.

Insufficient driving forces defined as the energetic offsets of the frontier molecular orbitals between a donor and an acceptor influence the charge separation in organic solar cells (OSCs), thus restricting the improvement of quantum efficiencies. Herein, we demonstrate that enhancing charge transfer between fullerene and non-fullerene acceptors via ternary strategy is an effective method to address this problem. By introducing an electron acceptor [6,6]-phenyl-C-butyric acid methyl ester (PCBM) as the third component to the binary blends based on the polymer donor of poly[(2,6-(4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)-benzo[1,2- b:4,5- b']dithiophene))- alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'- c:4',5'- c']dithiophene-4,8-dione)] (PBDB-TF) and the small-molecule acceptor of 2,2'-((2 Z,2' Z)-(((2,5-difluoro-1,4-phenylene)bis(4,4-bis(2-ethylhexyl)-4 H-cyclopenta[2,1- b:3,4- b']dithiophene-6,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1 H-indene-2,1-diylidene))dimalononitrile (HF-PCIC) or 2,2'-((2 Z,2' Z)-(((2,5-difluoro-1,4-phenylene)bis(4,4-bis(2-ethylhexyl)-4 H-cyclopenta[2,1- b:3,4- b']dithiophene-6,2-diyl))bis(methanylylidene))bis(5,6-dichloro-3-oxo-2,3-dihydro-1 H-indene-2,1-diylidene))dimalononitrile (HC-PCIC) with unfused cores, the quantum efficiencies can be boosted from ∼70% for binary blends to over 80% for ternary blends in the longer wavelength ranges.

Nonhalogenated Solvent-Processed All-Polymer Solar Cells over 7.4% Efficiency from Quinoxaline-Based Polymers.

Two conjugated polymers, with different side chains of alkoxy-substituted difluorobenzene and alkyl-substituted difluorobenzene based on quinoxaline (Qx) as the electron acceptor unit and benzodithiophene as the electron donor unit, named HFQx-T and HFAQx-T, were used as electron donor polymers to fabricate all-polymer solar cells (all-PSCs) with a naphthalenediimide-bithiophene n-type semiconducting polymer (N2200). Usually, halogenated solvents are harmful to natural environment and human beings, and solvent additives were disadvantageous in the process of roll-to-roll technology. The Qx-based polymers are successfully used to fabricate high-performance all-PSCs, which processed with the nonhalogenated solvent tetrahydrofuran (THF) at room temperature.

Near-Infrared Electron Acceptors with Fluorinated Regioisomeric Backbone for Highly Efficient Polymer Solar Cells.

Solar photon-to-electron conversion with polymer solar cells (PSCs) has experienced rapid development in the recent few years. Even so, the exploration of molecules and devices in efficiently converting near-infrared (NIR) photons into electrons remains critical, yet challenging. Herein presented is a family of near-infrared nonfullerene acceptors (NIR NFAs, T1-T4) with fluorinated regioisomeric A-Aπ-D-Aπ-A backbones for constructing efficient single-junction and tandem PSCs with photon response up to 1000 nm.

Guided Formation of Large Crystals of Organic and Perovskite Semiconductors by an Ultrasonicated Dispenser and Their Application as the Active Matrix of Photodetectors.

The crystallization of organic or perovskite semiconductors reflects the intermolecular interactions and crucially determines the charge transport in opto-electronic devices. In this report, we demonstrate and investigate the use of an ultrasonicated dispenser to guide the formation of crystals of organic and perovskite semiconductors. The moving speed of the dispenser affects the match between the concentration gradient and evaporation rate near the three-phase contact lines and thus the generation of various crystallization morphologies.

A Near-Infrared Photoactive Morphology Modifier Leads to Significant Current Improvement and Energy Loss Mitigation for Ternary Organic Solar Cells.

Herein, efficient organic solar cells (OSCs) are realized with the ternary blend of a medium band gap donor (poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione)] (PBDB-T)) with a low band gap acceptor (2,2'-((2Z,2'Z)-(((2,5-difluoro-1,4-phenylene)bis(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b']dithiophene-6,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (HF-PCIC)) and a near-infrared acceptor (2,2'-((2Z,2'Z)-(((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(4-((2-ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IEICO-4F)). It is shown that the introduction of IEICO-4F third component into PBDB-T:HF-PCIC blend increases the short-circuit current density () of the ternary OSC to 23.46 mA cm, with a 44% increment over those of binary devices.

Enhancing the Performance of Polymer Solar Cells via Core Engineering of NIR-Absorbing Electron Acceptors.

In order to utilize the near-infrared (NIR) solar photons like silicon-based solar cells, extensive research efforts have been devoted to the development of organic donor and acceptor materials with strong NIR absorption. However, single-junction organic solar cells (OSCs) with photoresponse extending into >1000 nm and power conversion efficiency (PCE) >11% have rarely been reported. Herein, three fused-ring electron acceptors with varying core size are reported.

Medium-Bandgap Small-Molecule Donors Compatible with Both Fullerene and Nonfullerene Acceptors.

Much effort has been devoted to the development of new donor materials for small-molecule organic solar cells due to their inherent advantages of well-defined molecular weight, easy purification, and good reproducibility in photovoltaic performance. Herein, we report two small-molecule donors that are compatible with both fullerene and nonfullerene acceptors. Both molecules consist of an (E)-1,2-di(thiophen-2-yl)ethane-substituted (TVT-substituted) benzo[1,2-b:4,5-b']dithiophene (BDT) as the central unit, and two rhodanine units as the terminal electron-withdrawing groups.

A Ladder-type Heteroheptacene 12H-Dithieno[2',3':4,5]thieno[3,2-b:2',3'-h]fluorene Based D-A Copolymer with Strong Intermolecular Interactions toward Efficient Polymer Solar Cells.

Ladder-type electron-donating units for D-A copolymers applied in polymer solar cells usually comprise multiple tetrahedral carbon bridges bonded with out-of-plane alkyl chains for desirable solubility for device processing. However, molecular packing of resultant copolymers in the solid state and charge transport within devices are also impeded in spite of with multiple fused aromatic backbones. To mitigate this issue, a structurally well-defined ladder-type electron-donating heteroheptacene, 12H-dithieno[2',3':4,5]thieno[3,2-b:2',3'-h]fluorene (DTTF) with an extended conjugated backbone and a single tetrahedral carbon bridge attached with two bulky alkyl chains was designed and synthesized.

Fused Hexacyclic Nonfullerene Acceptor with Strong Near-Infrared Absorption for Semitransparent Organic Solar Cells with 9.77% Efficiency.

A fused hexacyclic electron acceptor, IHIC, based on strong electron-donating group dithienocyclopentathieno[3,2-b]thiophene flanked by strong electron-withdrawing group 1,1-dicyanomethylene-3-indanone, is designed, synthesized, and applied in semitransparent organic solar cells (ST-OSCs). IHIC exhibits strong near-infrared absorption with extinction coefficients of up to 1.6 × 10 m cm , a narrow optical bandgap of 1.

Realizing Small Energy Loss of 0.55 eV, High Open-Circuit Voltage >1 V and High Efficiency >10% in Fullerene-Free Polymer Solar Cells via Energy Driver.

A new, easy, and efficient approach is reported to enhance the driving force for charge transfer, break tradeoff between open-circuit voltage and short-circuit current, and simultaneously achieve very small energy loss (0.55 eV), very high open-circuit voltage (>1 V), and very high efficiency (>10%) in fullerene-free organic solar cells via an energy driver.

Fused Nonacyclic Electron Acceptors for Efficient Polymer Solar Cells.

We design and synthesize four fused-ring electron acceptors based on 6,6,12,12-tetrakis(4-hexylphenyl)-indacenobis(dithieno[3,2-b;2',3'-d]thiophene) as the electron-rich unit and 1,1-dicyanomethylene-3-indanones with 0-2 fluorine substituents as the electron-deficient units. These four molecules exhibit broad (550-850 nm) and strong absorption with high extinction coefficients of (2.1-2.

Molecular Lock: A Versatile Key to Enhance Efficiency and Stability of Organic Solar Cells.

4,4'-Biphenol (BPO), a common, cheap chemical, is employed as a "molecular lock" in blends of fluorine-containing polymer or small molecule donors and fullerene acceptors to lock donors via hydrogen bond formed between the donor and BPO. The molecular lock is a versatile key to enhance the efficiency and stability of organic solar cells simultaneously.

Improving polymer/nanocrystal hybrid solar cell performance via tuning ligand orientation at CdSe quantum dot surface.

Achieving superior solar cell performance based on the colloidal nanocrystals remains challenging due to their complex surface composition. Much attention has been devoted to the development of effective surface modification strategies to enhance electronic coupling between the nanocrystals to promote charge carrier transport. Herein, we aim to attach benzenedithiol ligands onto the surface of CdSe nanocrystals in the "face-on" geometry to minimize the nanocrystal-nanocrystal or polymer-nanocrystal distance.