A variety
of defects exist on the crystalline surfaces of solution-processed
polycrystalline perovskites, resulting in photovoltaic output losses
and subsequent degradations. It is necessary to develop a versatile
passivator that can concurrently eliminate multiple defects, including
vacancy, interstitial, antisite substitution, and dissociative I2. Herein, we focus on multiple-defect management to optimize
defective perovskite surfaces by using three kinds of chemical bonds
with a pyridine-containing polymeric agent. Coordination bonds alleviate
the distorted PbI
x
octahedrons by digesting
I vacancies, and hydrogen bonds stabilize ammonium cations to eliminate
organic vacancies and deep-level antisite defects. Furthermore, the
dissociated I2 acting as electron traps from the coupled
I interstitials could be blocked by supramolecular halogen bonds.
Based on the low-defect perovskite films, substantial increases in
photovoltaic efficiencies, going up to 22.02% and 23.14%, are achieved
in planar and mesoporous devices, respectively, with nonencapsulated
cells retaining 90% of their original efficiencies after 2200 h of
aging in ambient conditions.
Stimuli-responsive
supramolecular organogels are fascinating for
their dynamically controllable features, but it is difficult for most
versatile linear vinyl polymers to construct suitable cross-linking
points in oils or organic solvents. Here, a mesomorphic organogelator
was fabricated by self-assembly of one azopyridine-containing polymer
and oleic acid for the first time. Particularly, oleic acid acts as
not only one important component to construct the mesogenic gelator
but also the solvent entrapped in the interstices of the physically
cross-linked three-dimensional (3D) network. The resulting organogel
shows a macroscopic gel–sol transition upon external triggers
of temperature, light, and organic metal ions. Accordingly, holographic
gratings were successfully inscribed in the organogel, whose switching
behaviors were obtained by manipulation of the three external stimuli.
This provides a simple and elegant strategy to construct multiresponsive
supramolecular liquid-crystalline polymer organogels with promising
applications in optics, data storage, and sensors.
Hydrogen peroxide (HO) is an important reactive oxygen species (ROS). Maintaining the HO concentration at a normal level is critical to achieve the normal physiological activities of cells, which otherwise might trigger various diseases. Therefore, it is necessary to develop new and practical multisignaling sensors for both visualization of intracellular HO and accurate detection of extracellular HO. In this paper, a novel multichannel signaling fluorescence-electrochemistry combined probe 1 (FE-HO) is presented for imaging and detection of HO in living cell systems. In our design, the probe FE-HO consists of a HO reaction site and 4-ferrocenyl(vinyl)pyridine unit which affords chromogenic, fluorescent, and electrochemical signals. These structural motifs yield a combined chromogenic, fluorescent, and redox sensor in a single molecule. Probe FE-HO showed a "Turn-On" fluorescence response to HO, which can be used for monitoring intracellular HO in vivo. Furthermore, the electrochemical response of probe FE-HO was decreased after the addition of HO, which can be applied for accurate detection of HO released from living cells. When the fluorescence imaging method is combined with electrochemical analysis technology, it is hopeful that the well-designed multimodule probe can serve as a practical tool for understanding the metabolism and homeostasis of HO in a complex biological system.
Mitochondrial quality control prevents accumulation of intramitochondrial-derived reactive oxygen species (mtROS), thereby protecting cells against DNA damage, genome instability, and programmed cell death. However, underlying mechanisms are incompletely understood, particularly in fungal species. Here, we show that Cryptococcus neoformans heat shock factor 3 (CnHsf3) exhibits an atypical function in regulating mtROS independent of the unfolded protein response. CnHsf3 acts in nuclei and mitochondria, and nuclear- and mitochondrial-targeting signals are required for its organelle-specific functions. It represses the expression of genes involved in the tricarboxylic acid cycle while promoting expression of genes involved in electron transfer chain. In addition, CnHsf3 responds to multiple intramitochondrial stresses; this response is mediated by oxidation of the cysteine residue on its DNA binding domain, which enhances DNA binding. Our results reveal a function of HSF proteins in regulating mtROS homeostasis that is independent of the unfolded protein response.
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