A Tumor Environment-Activated Photosensitized Biomimetic Nanoplatform for Precise Photodynamic Immunotherapy of Colon Cancer.

Aggressive nature of colon cancer and current imprecise therapeutic scenarios simulate the development of precise and effective treatment strategies. To achieve this, a tumor environment-activated photosensitized biomimetic nanoplatform (PEG2000-SiNcTI-Ph/CpG-ZIF-8@CM) is fabricated by encapsulating metal-organic framework loaded with developed photosensitizer PEG2000-SiNcTI-Ph and immunoadjuvant CpG oligodeoxynucleotide within fusion cell membrane expressing programmed death protein 1 (PD-1) and cluster of differentiation 47 (CD47). By stumbling across, systematic evaluation, and deciphering with quantum chemical calculations, a unique attribute of tumor environment (low pH plus high concentrations of adenosine 5'-triphosphate (ATP))-activated photodynamic effect sensitized by long-wavelength photons is validated for PEG2000-SiNcTI-Ph/CpG-ZIF-8@CM, advancing the precision of cancer therapy. Moreover, PEG2000-SiNcTI-Ph/CpG-ZIF-8@CM evades immune surveillance to target CT26 colon tumors in mice mediated by CD47/signal regulatory proteins α (SIRPα) interaction and PD-1/programmed death ligand 1 (PD-L1) interaction, respectively. Tumor environment-activated photodynamic therapy realized by PEG2000-SiNcTI-Ph/CpG-ZIF-8@CM induces immunogenic cell death (ICD) to elicit anti-tumor immune response, which is empowered by enhanced dendritic cells (DC) uptake of CpG and PD-L1 blockade contributed by the nanoplatform. The photodynamic immunotherapy efficiently combats primary and distant CT26 tumors, and additionally generates immune memory to inhibit tumor recurrence and metastasis. The nanoplatform developed here provides insights for the development of precise cancer therapeutic strategies.

Halogen-Free Donor Polymers Based on Dicyanobenzotriazole with Low Energy Loss and High Efficiency in Organic Solar Cells.

Halogenation of organic semiconductors is an efficient strategy for improving the performance of organic solar cells (OSCs), while the introduction of halogens usually involves complex synthetic process and serious environment pollution problems. Herein, three halogen-free ternary copolymer donors (PCNx, x = 3, 4, 5) based on electron-withdrawing dicyanobenzotriazole are reported. When blended with the Y6, PCN3 with strong interchain interactions results in appropriate crystallinity and thermodynamic miscibility of the blend film. Grazing-incidence wide-angle X-ray scattering measurements indicate that PCN3 has more ordered arrangement and stronger π-π stacking than previous PCN2. Fourier-transform photocurrent spectroscopy and external quantum efficiency of electroluminescence measurements show that PCN3-based OSCs have lower energy loss than PCN2, which leads to their higher open-circuit voltage (0.873 V). The device based on PCN3 reaches power conversion efficiency (PCE) of 15.33% in binary OSCs, one of the highest values for OSCs with halogen-free donor polymers. The PCE of 17.80% and 18.10% are obtained in PM6:PCN3:Y6 and PM6:PCN3:BTP-eC9 ternary devices, much higher than those of PM6:Y6 (16.31%) and PM6:BTP-eC9 (17.33%) devices. Additionally, this ternary OSCs exhibit superior stability compared to binary host system. This work gives a promising path for halogen-free donor polymers to achieve low energy loss and high PCE.

Pricing extreme mortality risk in the wake of the COVID-19 pandemic.

In pricing extreme mortality risk, it is commonly assumed that interest rate and mortality rate are independent. However, the COVID-19 pandemic calls this assumption into question. In this paper, we employ a bivariate affine jump-diffusion model to describe the joint dynamics of interest rate and excess mortality, allowing for both correlated diffusions and joint jumps. Utilizing the latest U.S. mortality and interest rate data, we find a significant negative correlation between interest rate and excess mortality, and a much higher jump intensity when the pandemic experience is considered. Moreover, we construct a risk-neutral pricing measure that accounts for both diffusion and jump risk premia, and we solve for the market prices of risk based on mortality bond prices. Our results show that the pandemic experience can drastically change investors' perception of the mortality risk market in the post-pandemic era.

A Bionic Interface to Suppress the Coffee-Ring Effect for Reliable and Flexible Perovskite Modules with a Near-90% Yield Rate.

The inhomogeneity, poor interfacial contact, and pinholes caused by the coffee-ring effect severely affect the printing reliability of flexible perovskite solar cells (PSCs). Herein, inspired by the bio-glue of barnacles, a bionic interface layer (Bio-IL) of NiOx /levodopa is introduced to suppress the coffee-ring effect during printing perovskite modules. The coordination effect of the sticky functional groups in Bio-IL can pin the three-phase contact line and restrain the transport of perovskite colloidal particles during the printing and evaporation process. Moreover, the sedimentation rate of perovskite precursor is accelerated due to the electrostatic attraction and rapid volatilization from an extraordinary wettability. The superhydrophilic Bio-IL affords an even spread over a large-area substrate, which boosts a complete and uniform liquid film for heterogeneous nucleation as well as crystallization. Perovskite films on different large-area substrates with negligible coffee-ring effect are printed. Consequently, inverted flexible PSCs and perovskite solar modules achieve a high efficiency of 21.08% and 16.87%, respectively. This strategy ensures a highly reliable reproducibility of printing PSCs with a near 90% yield rate.

Enhanced Efficiency and Excellent Thermostability in Organic Photovoltaics via Ternary Strategy with Twisted Conjugated Compound.

The thermal stability of high-efficiency organic photovoltaics (OPVs) is critical to the manufacturing of this technology. Therefore, targeted strategies and approaches shall be developed to improve efficiency and stability, simultaneously. Herein, a seleno twisted benzodiperylenediimides (TBD-PDI-Se) acceptor-doping strategy is taken advantage of to demonstrate the ternary bulk heterojunction OPVs with excellent stability, achieving outstanding power conversion efficiency of 14.43% and 17.25% based on PM6:IT-4F and PM6:Y6 ternary blend devices, respectively, which are superior to the corresponding binary devices. As evidenced by the active layer morphology, exciton dynamic study and the characterizations of the enabled device, the ternary blend device keeps nearly 90% original efficiency (t = 1000 h) under continuous constant heating at 140 °C. Furthermore, the application of acceptor as the third component in PBDB-T:ITIC, J71:ITIC, and PBDB-T:PC71 BM systems is also verified, proving the good universality of acceptor-doping ternary strategy.

Layer-by-Layer Solution-Processed Organic Solar Cells with Perylene Diimides as Acceptors.

Layer-by-layer (LBL) sequential solution processing of the active layer has been proven as an effective strategy to improve the performance of organic solar cells (OSCs), which could adjust vertical phase separation and improve device performance. Although perylene diimide (PDI) derivatives are typical acceptors with excellent photoelectric properties, there are few studies on PDI-based LBL OSCs. Herein, three PDI acceptors (TBDPDI-C5, TBDPDI-C11, and SdiPDI) were used to fabricate LBL and bulk heterojunction (BHJ) OSCs, respectively. A series of studies including device optimization, photoluminescence (PL) quenching, dependence of light intensity, carrier mobility, atomic force microscopy (AFM), transmission electron microscopy (TEM), grazing-incidence wide-angle X-ray scattering (GIWAXS), and depth analysis X-ray photoelectron spectroscopy (DXPS) were carried out to make clear the difference of the PDI-based LBL and BHJ OSCs. The results show that LBL OSCs possess better charge transport, higher and more balanced carrier mobility, less exciton recombination loss, more favorable film morphology, and proper vertical component distribution. Therefore, all the three PDI acceptor-based LBL OSCs exhibit higher performance than their BHJ counterparts. Among them, TBDPDI-C5 performs best with a power conversion efficiency of 6.11% for LBL OSCs, higher than its BHJ OSC (5.14%). It is the first time for PDI small molecular acceptors to fabricate high-efficiency OSCs by using an LBL solution-processed method.

Silicon Naphthalocyanine Tetraimides: Cathode Interlayer Materials for Highly Efficient Organic Solar Cells.

Naphthalocyanine derivatives (SiNcTI-N and SiNcTI-Br) were firstly used as excellent cathode interlayer materials (CIMs) in organic solar cells, via introducing four electron-withdrawing imide groups and two hydrophilic alkyls. Both of them showed deep LUMO energy levels (below -3.90 eV), good thermal stability (Td >210 °C), and strong self-doping property. The SiNcTI-Br CIM displayed high conductivity (4.5×10-5  S cm-1 ) and electron mobility (7.81×10-5  cm2 V-1 s-1 ), which could boost the efficiencies of the PM6:Y6-based OSCs over a wide range of CIM layer thicknesses (4-25 nm), with maximum efficiency of 16.71 %.

Dually-Passivated Perovskite Solar Cells with Reduced Voltage Loss and Increased Super Oxide Resistance.

In recent years, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has witnessed rapid progress. Nevertheless, the pervasive defects prone to non-radiative recombination and decomposition exist at the surface and the grain boundaries (GBs) of the polycrystalline perovskite films. Herein, we report a comprehensive dual-passivation (DP) strategy to effectively passivate the defects at both surface and GBs to enhance device performance and stability further. Firstly, a fluorinated perylene-tetracarboxylic diimide derivative is permeated in the perovskite metaphase during antisolvent treatment, and then a fluorinated bulky aromatic ammonium salt is introduced over the annealed perovskite. The reduction of defect density can be unambiguously proved by the superoxide species generation/quenching reaction. As a result, optimized planar PSCs demonstrate a decreased open-circuit voltages deficit from 0.47 to 0.39 V and the best efficiency of 23.80 % from photocurrent scanning with a stabilized maximum power output efficiency of 22.99 %. Without encapsulation, one typical device can maintain over 85 % of the initial efficiency after heating on a hot plate at 100 °C for 30 h under relative humidity (RH) of 70 %. When the device is aged under 30±5 % RH, over 97 % of its initial PCE is retained after 1700 h.

Preaggregation Matching of Donors and Acceptors in Solution Accounting for Thermally Stable Non-Fullerene Solar Cells.

The mechanism of how the solvent type influences photovoltaic performance and thermal stability of non-fullerene organic solar cells remains unexplored. In this article, the well-known PTB7-Th was selected as a donor, while F8IC was used as an acceptor. The PTB7-Th:F8IC processed from chloroform (CF) exhibited a superiorly higher power conversion efficiency (PCE) of 10.5%, in contrast to the specimen processed from chlorobenzene (CB) of 6.8%. In addition, upon thermal annealing at 160 °C for 120 min, the device processed from CF was more stable than that processed from CB. The incorporation of perylene diimide derivative TBDPDI-C11, serving as the third additive, could also obviously improve the PCE value and thermal stability of PTB7-Th:F8IC processed from CB. According to ultraviolet spectroscopy, atomic force microscopy, transmission electron microscopy, and grazing incidence wide-angle X-ray scattering analyses, the enhanced photovoltaic performance and thermal stability are mainly attributed to formation of PTB7-Th nanofibers and appropriate aggregation of F8IC. The interaction free energy calculated using water and diiodomethane contact angles reveals that PTB7-Th well disperses in CB and tends to aggregate in CF, while F8IC aggregates strongly in CB. The preaggregation matching of the donor and acceptor in solution is essential for the optimization of morphology, efficiency, and thermal stability. The findings in this article could provide useful guidelines to fabricate efficient and thermally stable organic solar cells simply by analyzing the surface energy of components processed from different solvents.

"Double-Acceptor-Type" Random Conjugated Terpolymer Donors for Additive-Free Non-Fullerene Organic Solar Cells.

Random conjugated terpolymers (RCTs) not only promote great comprehension and realization for the state-of-the-art highly effective non-fullerene organic solar cells (OSCs) but also offer a simple and practical synthetic strategy. However, the photovoltaic properties of RCTs yet lagged behind that of the donor-acceptor (D-A) alternating copolymer, especially in additive-free devices. Hence, we developed two feasible "double-acceptor-type" random conjugated terpolymers, PBDB-TAZ20 and PBDB-TAZ40. The additive-free OSCs based on PBDB-TAZ20:ITIC and PBDB-TAZ40:ITIC exhibit decent efficiencies of 12.34 and 11.27%, respectively, which both surpass the PBDB-T:ITIC-based device. For RCTs, the reasonably weakened crystallinity and the reduced phase separation degree are demonstrated to help in improving charge transport, reducing bimolecular recombination, and thus enhancing the photovoltaic performance of additive-free OSCs. The results imply that adding a third moiety into the D-A polymer donors provides a simple but efficient synthetic approach for high-performance OSCs.

Thioether Bond Modification Enables Boosted Photovoltaic Performance of Nonfullerene Polymer Solar Cells.

A small-molecule nonfullerene acceptor, ITIC-S, bearing a fused heptacyclic benzodi(cyclopentadithiophene) core with a thioether-bond-substituted thiophene, is designed, synthesized, and compared with its alkyl-substituted analog, ITIC2. Compared with ITIC2, ITIC-S with a thioether bond exhibits higher electron mobility, a slightly larger optical band gap, and similar absorption. The active layer incorporating ITIC-S and the wide-bandgap polymeric donor PBDB-T-SF displays a smaller crystalline coherent length of π-π stacking, more balanced mobilities, weaker bimolecular recombination, and more effective charge collection than its PBDB-T-SF:ITIC2 counterpart. Accordingly, polymer solar cells incorporating ITIC-S and PBDB-T-SF demonstrate a fill factor (FF) of 66.8% and a champion power conversion efficiency (PCE) of 11.6%, exceeding those of the PBDB-T-SF:ITIC2 blend (PCE = 10.1%, FF = 59.7%), which shows that the thioether bond substitution strategy is an easy yet viable way for designing high-performance electron acceptors.

Subphthalocyanine Triimides: Solution Processable Bowl-Shaped Acceptors for Bulk Heterojunction Solar Cells.

Ten subphthalocyanine triimides (SubPcTI) with different substituents at imide sites and B atoms were designed and synthesized. These compounds with low-lying lowest unoccupied molecular orbital energy levels (from -3.91 to -3.98 eV), strong absorption in the range of 450-650 nm, and adjustable solubility are expected to be excellent electron acceptors. Non-fullerene bulk heterojunction organic solar cells based on acceptor 8c showed power conversion efficiency of 4.92%, which is the highest value among subphthalocyanine derivatives.

Seleno twisted benzodiperylenediimides: facile synthesis and excellent electron acceptors for additive-free organic solar cells.

Seleno twisted benzodiperylenediimides (TBDPDI-Se) as promising electron acceptor chromophores were designed and synthesized using a facile strategy with which different side chains could be introduced readily. Bulk heterojunction organic solar cells based on these acceptors exhibit the highest power conversion efficiency of 7.41% without any additive treatment.

Efficient resolution of venlafaxine and mechanism study via X-ray crystallography.

Numbers of resolving factors were investigated to improve resolution of venlafaxine 1. An effective resolving agent, O,O'-di-p-toluoyl-(R, R)-tartaric acid 2, was screened using similar method of 'Dutch resolution' from tartaric acid derivatives. The resolution efficiency was up to 88.4%, when the ratio of rac-1 and 2 was 1:0.8 in THF with little water (10:1 v/v). Enantiomerically pure venlafaxine was prepared with 99.1% ee in 82.2% yield. The chiral resolution mechanism was first explained through X-ray crystallographic study. One diastereomeric salt with well solubility forms a columnar supramolecular structure as the acidic salt (R)-1·2, while the other diastereomeric salt with less solubility forms a multilayered sandwich supramolecular structure by enantio-differentiation self-assembly as the neutral salt 2(S)-1·2. The water molecules play a key role in the optical resolution, as indicated by the special structures of the diastereomeric salts.

Facile Approach to Perylenemonoimide with Short Side Chains for Nonfullerene Solar Cells.

Electron acceptors based on perylene monoimide (PMI) are rare due to the synthetic challenge. Herein, starting from commercially available perylene dianhydride, brominated perylene monoimide (PMI-Br) with short side chains and good solubility was efficiently synthesized in a high overall yield of 71%. With PMI-Br as the intermediate, acceptor-donor-acceptor type electron acceptors with low-lying LUMO energy levels and strong visible absorption were successfully obtained. The nonfullerene bulk heterojunction solar cells based on these acceptors were fabricated with the highest PCE of 1.3%.

(o-Phenyleno)naphthalene diimides: a pink fluorescent chromophore.

(o-Phenyleno)naphthalene dianhydride 7 was synthesized by a six-step reaction. Imidizations of 7 led to various diimides 8. Their optical and electrochemical properties hold promise for organic electronics.

Rylene and Rylene Diimides: Comparison of Theoretical and Experimental Results and Prediction for High-Rylene Derivatives.

Low rylene (R) and rylene diimides (RD) are important organic semiconductors and dyes. High R and RD with larger conjugated cores show different properties compared with their low counterparts. Herein, absorption spectra, frontier molecular orbitals, band gaps, inner-sphere reorganization energy (λi), ionization potential, electron affinity, and atomic charge population of 20 rylene compounds were calculated by the density functional theory method. The theoretical results agree well with experimental ones. We predict some unusual properties of some high rylene derivatives that are unknown compounds due to synthetic difficulties. The lowest unoccupied molecular orbital energy levels of RD compounds change slightly, from -3.61 to -3.79 eV, which makes them strong electron acceptors. The band gaps narrow with the size increase of conjugated cores, which makes high rylene derivatives near-infrared dyes. The rising highest occupied molecular orbital energy levels of high rylene derivatives makes them unstable in the air. The λi falls with the size increase of the conjugated core, and the size of RD-4 or R-4 is big enough for the small λi to favor charge transport. The charge population analysis indicates R and RD have different charge distribution under the effect of electron-withdrawing imide groups, which contributes to distinct properties.

Core-Fluorinated Naphthalene Diimides: Synthesis, Characterization, and Application in n-Type Organic Field-Effect Transistors.

A series of difluoro- and tetrafluoro-substituted naphthalene diimides (NDIs) were synthesized by halogen exchange reactions of corresponding bromo-NDIs with CsF in dioxane. Two strong electron acceptor molecules 6 and 8 with low-lying LUMO energy levels of -4.27 and -4.54 eV were obtained, starting from tetrafluoro-NDI. Organic field-effect transistors (OFETs) based on these fluorinated NDIs were fabricated by vapor deposition, exhibiting n-channel field-effect character under ambient conditions with the highest mobility of 0.1 cm(2) V(-1) s(-1).

A crown ether decorated dibenzocoronene tetracarboxdiimide chromophore: synthesis, sensing, and self-organization.

A macrocyclic dibenzocoronene tetracarboxdiimide containing two benzo-21-crown-7 groups has been synthesized. It shows liquid-crystalline behavior and selectively binds Pb(2+) or K(+) to form 1:2 complexes in solution. The complexation leads to a significant increase of fluorescence; the surface organization of discotic columnar structures, in the solid-state, can be controlled by selective ion binding.

Flow-assisted 2D polymorph selection: stabilizing metastable monolayers at the liquid-solid interface.

Controlling crystal polymorphism constitutes a formidable challenge in contemporary chemistry. Two-dimensional (2D) crystals often provide model systems to decipher the complications in 3D crystals. In this contribution, we explore a unique way of governing 2D polymorphism at the organic liquid-solid interface. We demonstrate that a directional solvent flow could be used to stabilize crystalline monolayers of a metastable polymorph. Furthermore, flow fields active within the applied flow generate millimeter-sized domains of either polymorph in a controlled and reproducible fashion.