Singlet fission (SF) in two or more electronically coupled organic chromophores converts a high-energy singlet exciton into two low-energy triplet excitons, which can be used to increase solar cell efficiency. Many known SF chromophores are unsuitable for device applications due to chemical instability and low triplet state energies. The results described here show that efficient SF occurs in polycrystalline thin films of 9,10bis(phenylethynyl)anthracene (BPEA), a commercial dye that has singlet and triplet energies of 2.40 and 1.11 eV, respectively, in the solid state. BPEA crystallizes into two polymorphs with space groups C2/c and Pbcn, which undergo SF with kSFA = (109 ± 4 ps) −1 and kSFB = (490 ± 10 ps) −1 , respectively. The high triplet energy and efficient SF evidenced from the 180 ± 20% triplet yield make BPEA a promising candidate for enhancing solar cell performance.

Protection of enzymes with synthetic materials is a viable strategy to stabilize, and hence to retain, the reactivity of these highly active biomolecules in non-native environments. Active synthetic supports, coupled to encapsulated enzymes, can enable efficient cascade reactions which are necessary for processes like light-driven CO2 reduction, providing a promising pathway for alternative energy generation. Herein, a semi-artificial systemcontaining an immobilized enzyme, formate dehydrogenase, in a light harvesting scaffoldis reported for the conversion of CO2 to formic acid using white light. The electron-mediator Cp*Rh­(2,2′-bipyridyl-5,5′-dicarboxylic acid)­Cl was anchored to the nodes of the metal–organic framework NU-1006 to facilitate ultrafast photo-induced electron transfer when irradiated, leading to the reduction of the coenzyme nicotinamide adenine dinucleotide at a rate of about 28 mM·h–1. Most importantly, the immobilized enzyme utilizes the reduced coenzyme to generate formic acid selectively from CO2 at a high turnover frequency of about 865 h–1 in 24 h. The outcome of this research is the demonstration of a feasible pathway for solar-driven carbon fixation.

Air-stable and soluble tetrabutylammonium fluoride (TBAF) is demonstrated as an efficient n-type dopant for the conjugated polymer ClBDPPV. Electron transfer from F anions to the π-electron-deficient ClBDPPV through anion-π electronic interactions is strongly corroborated by the combined results of electron spin resonance, UV-vis-NIR, and ultraviolet photoelectron spectroscopy. Doping of ClBDPPV with 25 mol% TBAF boosts electrical conductivity to up to 0.62 S cm , among the highest conductivities that have been reported for solution-processed n-type conjugated polymers, with a thermoelectric power factor of 0.63 µW m K in air. Importantly, the Seebeck coefficient agrees with recently published correlations to conductivity. Moreover, the F -doped ClBDPPV shows significant air stability, maintaining the conductivity of over 0.1 S cm in a thick film after exposure to air for one week, to the best of our knowledge the first report of an air-stable solution-processable n-doped conductive polymer with this level of conductivity. The result shows that using solution-processable small-anion salts such as TBAF as an n-dopant of organic conjugated polymers possessing lower LUMO (lowest unoccupied molecular orbital), less than -4.2 eV) can open new opportunities toward high-performance air-stable solution-processable n-type thermoelectric (TE) conjugated polymers.

Cancer‐associated fibroblasts (CAFs) play a key role in orchestrating the tumor malignant biological properties within tumor microenvironment and evidences demonstrate that CAFs are a critical regulator of tumoral immunosuppression of the T cell response. However, the functions and regulation of CAFs in the expression of programmed death‐ligand 1 (PD‐L1) in melanoma and colorectal carcinoma (CRC) are not completely understood. Herein, by scrutinizing the expression of α‐SMA and PD‐L1 in melanoma and CRC tissues, we found that CAFs was positive correlated with PD‐L1 expression. Further analyses showed that CAFs promoted PD‐L1 expression in mice tumor cells. By detecting a majority of cytokines expression in normal mice fibroblasts and CAFs, we determined that CXCL5 was abnormal high expression in CAFs and the immunohistochemistry and in situ hybridization confirmed that were CAFs which were expressing CXCL5. In addition, CXCL5 promoted PD‐L1 expression in B16, CT26, A375 and HCT116. The silencing of CXCR2, the receptor of CXCL5, inhibited the PD‐L1 expression induced by CAFs in turn. Functionally, CXCL5 derived by CAFs promoted PD‐L1 expression in mice tumor cells through activating PI3K/AKT signaling. LY294002, the inhibitor of PI3K, confirmed that CXCL5 forested an immunosuppression microenvironment by promoting PD‐L1 expression via PI3K/AKT signaling. Meanwhile, the B16/CT26 xenograft tumor models were used and both CXCR2 and p‐AKT were found to be positively correlated with PD‐L1 in the xenograft tumor tissues. The immunosuppressive action of CAFs on tumor cells is probably reflective of them being a potential therapeutic biomarker for melanoma and CRC.

Excited-state symmetry-breaking charge separation (SB-CS) can offer an efficient pathway to solar energy capture and conversion. We synthesized a series of 1,6,7,12-tetrakis­(4-t-butylphenoxy)­perylene­(3,4:9,10)­bis­(dicarboximide) cyclophane dimers with m-xylylene, p-xylylene, and 4,4′-diyldimethane-1,1′-biphenyl spacers and studied them with steady-state and time-resolved optical spectroscopies. Photoinduced SB-CS occurs in all three cyclophanes in CH2Cl2, with the SB-CS rate decreasing as the interchromophore distance is increased. Time-resolved emission spectroscopy and kinetic modeling reveal that the charge-separated state exists in pseudoequilibrium with the excited state prior to decay. Notably, the meta-spaced cyclophane also undergoes SB-CS in toluene within ∼100 ps, despite the lack of charge stabilization by the low dielectric constant solvent. These results demonstrate that SB-CS can occur across long distances and in weakly polar environments, which offers the possibility of harnessing SB-CS for solar energy capture and conversion.