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Heterostructured photocatalysts were fabricated by coupling electrospun n-type ZnO fibres and hydrothermally derived p-type CuCrO2 nanoparticles. The effect of the amount of CuCrO2 nanoparticles on the photocatalytic activity of the heterostructured photocatalyst was systematically investigated. The formation of the heterojunctions between the two semiconductors was revealed via detailed XRD, XPS, TEM and optical property measurements. The experimental results indicated that the optimal CuCrO2 amount in the composite photocatalyst was 1.0 wt.% due to the optimum doping and surface coverage, higher absorption onset edge, larger absorption intensity and optimum band gap energy. This composite photocatalyst, fabricated by drop casting of CuCrO2 nanoparticle dispersion on ZnO fibres, displayed 30% higher rate constant (k) value compared to the pure ZnO fibres in the degradation of methylene blue dye molecules and reached 93.4% decomposition in 1 h under UV-visible light exposure. The obtained results are highly encouraging in comparison to only UV/light active p-n heterostructured photocatalysts previously reported in literature. Therefore, we believe that the proposed approach here opened the way for simple synthesis of highly-efficient visible light active heterostructured semiconductor photocatalyst systems.

Herein, the long‐term stability of vacuum‐deposited methylammonium lead iodide (MAPbI3) perovskite solar cells (PSCs) with power conversion efficiencies (PCEs) of around 19% is evaluated. A low‐temperature atomic layer deposition (ALD) Al2O3 coating is developed and used to protect the MAPbI3 layers and the solar cells from environmental agents. The ALD encapsulation enables the MAPbI3 to be exposed to temperatures as high as 150 °C for several hours without change in color. It also improves the thermal stability of the solar cells, which maintain 80% of the initial PCEs after aging for ≈40 and 37 days at 65 and 85 °C, respectively. However, room‐temperature operation of the solar cells under 1 sun illumination leads to a loss of 20% of their initial PCE in 230 h. Due to the very thin ALD Al2O3 encapsulation, X‐ray diffraction can be performed on the MAPbI3 films and completed solar cells before and after the different stress conditions. Surprisingly, it is found that the main effect of light soaking and thermal stress is a crystal reorientation with respect to the substrate from (002) to (202) of the perovskite layer, and that this reorientation is accelerated under illumination.

In this study, it is aimed to develop glucose/fructose sensitive poly(ethylene glycol) methyl ether methacrylate (PEGMA) particles which can be employed in controlled drug delivery applications. For this purpose, a boric acid based crosslinker was synthesized using 4-vinylphenylboronic acid and its formation was confirmed by 1H-NMR and FT-IR analyses. Sugar-sensitive polymeric particles were then achieved using this crosslinker and PEGMA monomer in single step and surfactant free emulsion polymerization technique. Polymeric particles were characterized by DLS, SEM, and TEM in terms of size and morphology. In order to determine the sensitivity of the particles to sugar molecules, first Rhodamine B dye (as a model drug) loading experiments were performed. Then, the particles were subjected to glucose/fructose rich media and dye release was monitored as a function of time using UV-Vis spectrophotometry. The results of the current study revealed that the PEGMA particles were more sensitive to fructose (~39% release) compared to glucose (~25% release) at pH 7.4 and 310 K.