An NIR-II-emitting type-I photosensitizer for efficient hypoxic tumor phototheranostics.

A small molecule-based NIR-II type-I photosensitizer (IT-IC) with a strong push-pull effect and good planar π-conjugated structure was synthesized. The IT-IC NPs exhibited strong light absorption, outstanding NIR-II fluorescence emission, excellent photothermal conversion and efficient type-I/II ROS generation, showing encouraging therapeutic outcomes for hypoxic tumors.

Self-assembled hole-transporting material constructed by chlorination and conjugation strategies toward efficient organic solar cells.

The moderate charge-transporting capability together with higher-lying energetic levels of self-assembling hole-transporting materials (SAMs) constrain the productive carrier extraction dynamics. To alleviate this issue, a synergetic chlorination and extended conjugation strategy is applied to explore a novel HTL, named 2Cl-TPA-CN-COOH. Indeed, the chlorinated head backbone would deepen the energetic level and strengthen the intramolecular push-pull effect, whereas the elongated conjugation unit would boost the carrier-transporting potential. Consequently, a champion power conversion efficiency (PCE) of 18.6% with upgraded stability is obtained in a 2Cl-TPA-CN-COOH cell. These results demonstrate a new insight of the molecular configuration of SAMs, which would contribute to the enhancements of performance and reliability in the OSC field.

TD-DFT benchmark for UV-visible spectra of fused-ring electron acceptors using global and range-separated hybrids.

Non-fullerene acceptors, especially acceptor-donor-acceptor structured fused-ring electron acceptors (FREAs), have attracted widespread attention in organic solar cells because of their versatile molecular design in fine-tuning light absorption and energy levels. We report the accuracy of Time-Dependent Density Functional Theory (TD-DFT) for FREAs by comparing their theoretically predicted vertical absorption wavelength (λver-abso) with the experimental maximum absorption (λmax). The λver-abso values of 50 molecules obtained from major types of FREAs have been investigated using TD-DFT by considering the solvent effects. The values of λver-abso predicted with a pure density functional (PBE), global hybrids (B3LYP and PBE0) and range-separated schemes (CAM-B3LYP and LC-ωPBE) follow the exact exchange percentage included at an intermediate inter-electronic distance. Global hybrids outperform all other schemes. The mean absolute error provided is 22 nm by PBE0 and 38 nm by B3LYP for the whole set of molecules. The maximum deviation of 92 nm provided by B3LYP and 69 nm provided by PBE0 confirms that PBE0 is more appropriate for predicting the absorption wavelengths when designing new FREAs. By applying linear regression analysis to obtain the calibration curve, we found that the range-separated methods provide an equal or even more consistent description of FREA excited states. For the whole set of molecules, linearly corrected data yield an average error of 25 and 27 nm for CAM-B3LYP and LC-ωPBE, respectively. Consequently, when a statistical analysis technique is applicable for a certain series of FREAs, a theoretical method permits a chemically comprehensive and empirically good explanation of UV/Vis spectra for newly-designed FREAs.

High performance one-for-all phototheranostics: NIR-II fluorescence imaging guided mitochondria-targeting phototherapy with a single-dose injection and 808 nm laser irradiation.

Current phototheranostics is still encountering various impediments, which causes complicated and prolonged therapy, and increases unnecessary side effects and systemic toxicity to patients. Herein, mitochondria-targeting one-for-all phototheranostic nanoparticles based on single-component organic molecule were designed and fabricated. After being irradiated with a single 808 nm laser, outstanding second near-infrared (NIR-II) fluorescence signals (with a high fluorescence quantum yield of 2.2% in water) were obtained for NIR-II fluorescence imaging, which could efficiently locate tumor and real-time monitor the therapeutic process. Moreover, such nanoparticles also presented superb photothermal conversion efficiency (39.6%) and singlet oxygen yield (2.3%, almost 12 times higher than clinical NIR dye indocyanine green) under 808 nm laser illumination, which could produce both potent hyperthermia and abundant singlet oxygen, resultantly leading to the mitochondrial dysfunction and further cell apoptosis. Both in vitro and in vivo investigations demonstrated that such nanoagents displayed significantly tumor theranostic efficacy, resulting from single 808 nm laser triggered high performance NIR-II fluorescence imaging guided mitochondria-targeting phototherapy. It was noteworthy that only a single-dose injection and 808 nm laser irradiation were employed during in vivo treatment. We believe that the phototheranostic nanoparticles developed in this work will open up a new dimension in cancer theranostics.

Dithieno[3,2-b:2',3'-d]pyrrol Fused Nonfullerene Acceptors Enabling Over 13% Efficiency for Organic Solar Cells.

A new electron-rich central building block, 5,5,12,12-tetrakis(4-hexylphenyl)-indacenobis-(dithieno[3,2-b:2',3'-d]pyrrol) (INP), and two derivative nonfullerene acceptors (INPIC and INPIC-4F) are designed and synthesized. The two molecules reveal broad (600-900 nm) and strong absorption due to the satisfactory electron-donating ability of INP. Compared with its counterpart INPIC, fluorinated nonfullerene acceptor INPIC-4F exhibits a stronger near-infrared absorption with a narrower optical bandgap of 1.39 eV, an improved crystallinity with higher electron mobility, and down-shifted highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. Organic solar cells (OSCs) based on INPIC-4F exhibit a high power conversion efficiency (PCE) of 13.13% and a relatively low energy loss of 0.54 eV, which is among the highest efficiencies reported for binary OSCs in the literature. The results demonstrate the great potential of the new INP as an electron-donating building block for constructing high-performance nonfullerene acceptors for OSCs.