Combustion-Assisted Polyol Reduction Method to Prepare Highly Transparent and Efficient Pt Counter Electrodes for Bifacial Dye-Sensitized Solar Cells

A combustion-assisted polyol reduction (CPR) method has been developed to deposit electrocatalytically efficient and transparent Pt counter electrodes (CEs) for bifacial dye-sensitized solar cells (DSSCs). Compared with conventional thermal decomposition of Pt precursors, CPR allows for a decrease in reduction temperature to 150 °C. The low-temperature processing is attributed to adding an organic fuel, acetylacetone (Hacac), which provides extra heat to lower reduction energy. In addition, the stable Pt complexes can simultaneously be formed in ethylene glycol (EG) and Hacac system, which leads to Pt nanoparticle size regulation. A ratio of Hacac to EG is optimized to achieve excellent electrocatalytic activity and high visible light transmittance for CEs. The bifacial DSSCs fabricated with CPR-Pt CEs (EG : Hacac=1 : 16) reach efficiencies of 6.71±0.16% and 6.41±0.15% in front and back irradiations, respectively.

Hydroxycinnamic acid derivatives for UV-selective and visibly transparent dye-sensitized solar cells

Naturally abundant dyes are very attractive for the development of dye-sensitized solar cells (DSSCs). Hydroxycinnamic acid derivatives, such as caffeic acid (CA), ferulic acid (FA), and p-coumaric acid (PA), were considered for the selective harvesting of ultraviolet A (UVA) (315-400 nm) photons. Their spectroscopic and electrochemical properties were investigated both theoretically and experimentally. They were further successfully adopted as photosensitizers in UV-selective and visibly transparent DSSCs, which exhibited a power conversion efficiency of 0.22-0.38% under AM (air mass) 1.5G (global) illumination (100 mW/cm²) and 3.40-3.62% under UVA irradiation (365 nm, 115.22 mW/cm²), with a corresponding visible light transmittance (VLT) of 49.07-43.72% and a general color rendering index (R_a) of 93-90.

Ferroelectric PVDF nanofiber membrane for high-efficiency PM0.3 air filtration with low air flow resistance

The significant public health concerns related to particulate matter (PM) air pollutants and the airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have led to considerable interest in high-performance air filtration membranes. Highly ferroelectric polyvinylidene fluoride (PVDF) nanofiber (NF) filter membranes are successfully fabricated via electrospinning for high-performance low-cost air filtration. Spectroscopic and ferro-/piezoelectric analyses of PVDF NF show that a thinner PVDF NF typically forms a ferroelectric β phase with a confinement effect. A 70-nm PVDF NF membrane exhibits the highest fraction of β phase (87%) and the largest polarization behavior from piezoresponse force microscopy. An ultrathin 70-nm PVDF NF membrane exhibits a high PM_0.3 filtration efficiency of 97.40% with a low pressure drop of 51 Pa at an air flow of 5.3 cm/s owing to the synergetic combination of the slip effect and ferroelectric dipole interaction. Additionally, the 70-nm PVDF NF membrane shows excellent thermal and chemical stabilities with negligible filtration performance degradation (air filtration efficiency of 95.99% and 87.90% and pressure drop of 55 and 65 Pa, respectively) after 24 h of heating at 120 °C and 1 h immersion in isopropanol.

[Construction of 3β-HSD gene silencing cell line and its effects on apoptosis induced by DEHP]

Objective: To construct 3β-HSD gene shRNA lentivirus interference vecto, then transfect into human MCF-7 cells, and construct cell line with 3β-HSD gene silencing, finally to study the effects of 3β-HSD on apoptosis induced by di- (2-ethylhexyl) phthalate (DEHP) . Methods: According to the mRNA sequence of 3β-HSD gene provided by GenBank, three interference sequences were designed and connected to PLVX-shRNA2-puro after annealing. The recombinant lentivirus vector was transfected into 293FT cells, the virus supernatants were collected and infected with MCF-7 cells. After puromycin screening, MCF-7 cells with 3β-HSD gene silencing were constructed. The cells with 3β-HSD gene silencing were identified by real-time quantitative PCR and western blot. Then the 3β-HSD gene silencing cells and MCF-7 cells were treated at various doses of DEHP for 24 hours to detect the gene expression and protein expression of apoptosis genes including Bax, Caspase-3 and Caspase-8. Results: The interference sequence of 3β-HSD gene inserted into lentivirus vector PLVX-shRNA2-puro is consistent with the designed sequence. 3β-HSD gene expression level in MCF-7 cells with 3β-HSD gene silencing was 77% lower than than that of control MCF-7 cells. 3β-HSD protein level in MCF-7 cells with 3β-HSD gene silencing was 74% lower than that of control MCF-7 cells. After DEHP treatment in MCF-7 cells with 3β-HSD gene silencing and control MCF-7 cells, qRT-PCR results showed that Bax gene expression levels increased by 28%-54%, Caspase-3 gene increased by 13%-49%, Caspase-8 gene increased by 21%-70% in MCF-7 cells when compared with the control group. Additionally, in the 3β-HSD gene silencing cells, Bax gene expression level decreased by 11%-28%, Caspase-3 gene expression decreased by 12%-23%, Caspase-8 gene expression decreased by 11%-34%, compared with the same treatment group of MCF-7 cells. Western blot results showed that Bax protein expression level increased by 28%-61%, Caspase-3 protein expression level increased by 40%-48%, Caspase-8 protein increased by 31%-84% in MCF-7 cells when compared with the control group. In 3β-HSD gene silencing cells, Bax protein expression level increased by 11%-27%, Caspase-3 protein increased by 21%-40%, Caspase-8 protein increased by 12%-25%, compared with the same treatment group of MCF-7 cells. Conclusion: The stable 3β-HSD gene silencing cell line are successfully constructed in this study. DEHP can induce increased expression of apoptotic gene and protein. Silencing of 3β-HSD gene can inhibit the activation of apoptotic gene by DEHP in a certain degree.

Manganese Oxide Nanoparticle as a New p-Type Dopant for High-Performance Polymer Field-Effect Transistors

We report a new p-type dopant, manganese oxide (Mn₃O₄) nanoparticle, to enhance the performance of organic field-effect transistors (OFETs) with conjugated polymers, including poly(3-hexylthiophene-2,5-diyl), poly[[N,N 9-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,59-(2,29-bithiophene)], and poly[[2,5-bis(2-octyldodecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl]-alt-[[2,2'-(2,5-thiophene)bis-thieno(3,2b) thiophene]-5,5'-diyl]] (DPPT-TT). Incorporating a small amount of Mn₃O₄ nanoparticles in the semiconductor film significantly improved the hole mobility and decreased the threshold voltage for all OFETs, indicating efficient Mn₃O₄ nanoparticle p-type doping. The Mn₃O₄ nanoparticle showed a better doping efficiency than the widely used FeCl₃ dopant due to better mixability with the host conjugated polymers. In particular, doped DPPT-TT OFETs showed significantly improved mobility up to 2.35 (±0.4) cm²/(V·s) with enhanced air and operational stability at 0.1 wt % doping concentration from 1.2 cm²/(V·s) for pristine devices.

Universal diffusion-limited injection and the hook effect in organic thin-film transistors

The general form of interfacial contact resistance was derived for organic thin-film transistors (OTFTs) covering various injection mechanisms. Devices with a broad range of materials for contacts, semiconductors, and dielectrics were investigated and the charge injections in staggered OTFTs was found to universally follow the proposed form in the diffusion-limited case, which is signified by the mobility-dependent injection at the metal-semiconductor interfaces. Hence, real ohmic contact can hardly ever be achieved in OTFTs with low carrier concentrations and mobility, and the injection mechanisms include thermionic emission, diffusion, and surface recombination. The non-ohmic injection in OTFTs is manifested by the generally observed hook shape of the output conductance as a function of the drain field. The combined theoretical and experimental results show that interfacial contact resistance generally decreases with carrier mobility, and the injection current is probably determined by the surface recombination rate, which can be promoted by bulk-doping, contact modifications with charge injection layers and dopant layers, and dielectric engineering with high-k dielectric materials.

An improvement of performance in n-channel organic field effect transistors with N-phenyl[60]fulleropyrrolidines by molecular doping

The high performance of soluble [60]fulleropyrrolidine upon its use as the active layer of n-channel organic field-effect transistors (OFETs) is reported.

Improved electron transport properties of n-type naphthalenediimide polymers through refined molecular ordering and orientation induced by processing solvents

Two new NDI-based polymers, P(NDI2SiC₅-T2) and P(NDI2SiC₅-TTh) were synthesized to determine the role played by the choice of processing solvents.

Controlling charge injection properties in polymer field-effect transistors by incorporation of solution processed molybdenum trioxide

A simply synthesized MoO₃ is used as charge injection layers for printed p-type organic field-effect transistors (OFETs).