Simple Non-Fused Electron Acceptors Leading to Efficient Organic Photovoltaics.

Despite the remarkable progress achieved in recent years, organic photovoltaics (OPVs) still need work to approach the delicate balance between efficiency, stability, and cost. Herein, two fully non-fused electron acceptors, PTB4F and PTB4Cl, are developed via a two-step synthesis from single aromatic units. The introduction of a two-dimensional chain and halogenated terminals for these non-fused acceptors plays a synergistic role in optimizing their solid stacking and orientation, thus promoting an elongated exciton lifetime and fast charge-transfer rate in bulk heterojunction blends. As a result, PTB4Cl, upon blending with PBDB-TF polymer, has enabled single-junction OPVs with power conversion efficiencies of 12.76 %, representing the highest values among the reported fully unfused electron acceptors so far.

[Novel cationic liposome loading siRNA inhibits the expression of hepatitis B virus HBx gene].

In order to solve the problem of selection and in vivo delivery problem in siRNA treatment, hepatitis B virus (HBV) HBx gene which could be targeted by siRNA was studied. The siRNA expression plasmid which specific inhibits HBx expression was obtained by in vitro selection via a dual-luciferase plasmid including HBx-Fluc fusion protein expression domain. The selected siRNA expression plasmid was then encapsulated in PEG-modified cationic liposome, which was devoted into pharmacodynamic studies at both cellular and animal level. The results illustrated that the cationic liposome which encapsulated siRNA expression plasmid could effectively inhibit HBx gene expression both in vitro and in vivo.

Photodegradation of Organic Solar Cells under Visible Light and the Crucial Influence of Its Spectral Composition.

While wavelength-dependent photodegradation of organic solar cells (OSCs) under visible light is typically discussed in terms of UV/blue light-activated phenomena, we recently demonstrated wavelength-dependent degradation rates up to 660 nm for PM6:Y6. In this study, we systematically investigated this phenomenon for a broad variety of devices based on different donor:acceptor combinations. We found that the spectral composition of the light used for degradation, tuned in a spectral range from 457 to 740 nm and under high irradiances of up to 30 suns, has a crucial influence on the device stability of almost all tested semiconductors. The relevance of this phenomenon was investigated in the context of simulated AM1.5 illumination with metal halide lamps and white LEDs. It is concluded that the current stability testing protocols in OSC research have to be adjusted to account for this effect to reveal the underlying physics of this still poorly understood mechanism.

Simple Near-Infrared Electron Acceptors for Efficient Photovoltaics and Sensitive Photodetectors.

Although promising progress has been made in near-infrared (NIR) electron acceptors for broadening photoresponse of optoelectronics, there are still strong needs for efficient NIR materials with low synthetic complexities. In this work, three simple NIR acceptors are developed with absorption up to 1000 nm and possessing the same dithiophene cores with varied heteroatom linkages to carbon (C) atom for W1, to silicon (Si) for W2, and to nitrogen (N) for W3. It is found that the tuning of only one atom for simple acceptors can surprisingly lead to a large difference in photoelectric properties and solid stacking, as well as the performance in optoelectronics. Although quite simple, these electron acceptors, especially W1 (C), can also perform quite efficiently as organic photovoltaics (OPVs) as well as sensitive organic photodetectors (OPDs) when blended with PTB7-Th polymer. It is worthy to note that, among the representative NIR acceptors with over 950 nm absorption, W1 possesses one of the best figure-of-merit when considering the photoelectric performance versus synthetic complexity of materials. As a result, the PTB7-Th:W1-based OPDs reach a fast temporal response, ultralow-light intensity detection of 1.70 × 10-11 W·cm-2, and a high specific detectivity of 4.28 × 1012 cm·Hz1/2·W-1 at 830 nm, representing a highly sensitive self-powered OPD approach the commercial broadband silicon detectors. These simple structure materials provide a potential example for further application of NIR electron acceptor.