Hole‐Transfer Dependence on Blend Morphology and Energy Level Alignment in Polymer: ITIC Photovoltaic Materials

Bulk‐heterojunction organic photovoltaic materials containing nonfullerene acceptors (NFAs) have seen remarkable advances in the past year, finally surpassing fullerenes in performance. Indeed, acceptors based on indacenodithiophene (IDT) have become synonymous with high power conversion efficiencies (PCEs). Nevertheless, NFAs have yet to achieve fill factors (FFs) comparable to those of the highest‐performing fullerene‐based materials. To address this seeming anomaly, this study examines a high efficiency IDT‐based acceptor, ITIC , paired with three donor polymers known to achieve high FFs with fullerenes, PTPD3T , PBTI3T , and PBTSA3T . Excellent PCEs up to 8.43% are achieved from PTPD3T:ITIC blends, reflecting good charge transport, optimal morphology, and efficient ITIC to PTPD3T hole‐transfer, as observed by femtosecond transient absorption spectroscopy. Hole‐transfer is observed from ITIC to PBTI3T and PBTSA3T , but less efficiently, reflecting measurably inferior morphology and nonoptimal energy level alignment, resulting in PCEs of 5.34% and 4.65%, respectively. This work demonstrates the importance of proper morphology and kinetics of ITIC → donor polymer hole‐transfer in boosting the performance of polymer: ITIC photovoltaic bulk heterojunction blends.     

Interstitial Mo‐Assisted Photovoltaic Effect in Multilayer MoSe2 Phototransistors

Thin‐film transistors (TFTs) based on multilayer molybdenum diselenide (MoSe₂) synthesized by modified atmospheric pressure chemical vapor deposition (APCVD) exhibit outstanding photoresponsivity (103.1 A W^?1), while it is generally believed that optical response of multilayer transition metal dichalcogenides (TMDs) is significantly limited due to their indirect bandgap and inefficient photoexcitation process. Here, the fundamental origin of such a high photoresponsivity in the synthesized multilayer MoSe₂ TFTs is sought. A unique structural characteristic of the APCVD‐grown MoSe₂ is observed, in which interstitial Mo atoms exist between basal planes, unlike usual 2H phase TMDs. Density functional theory calculations and photoinduced transfer characteristics reveal that such interstitial Mo atoms form photoreactive electronic states in the bandgap. Models indicate that huge photoamplification is attributed to trapped holes in subgap states, resulting in a significant photovoltaic effect. In this study, the fundamental origin of high responsivity with synthetic MoSe₂ phototransistors is identified, suggesting a novel route to high‐performance, multifunctional 2D material devices for future wearable sensor applications.     

Modeling of the emission rates of methyl ethyl ketone and effects of additives on the emission rate

Abstract

VOC(Volatile organic compound) emission rate was modelled in this study. The effects of the different environmental factors and the additives upon the emission rates were also determined. The study was conducted in a test chamber and in the field for determination of the emission rate of methyl ethyl ketone (MEK). Additionally, the theory of mass transfer was used to derive an MEK emission model with three variables (temperature, humidity, ventilation rate) and five coefficients (T ₁, R ₁, K_B , ACH_std and C_std ); these were determined by the results of emission rate in a test chamber. The emission rate of MEK ranged from 16.1 × 10³ to 101.0 × 10³ mg/m²/hr/(g‐MEK) for those cases which used solvents and plasticizer, and from 5.6×10³ to 58.1×10³ mg/m²/hr/(g‐MEK) when PVC powder was added. Additionally, the MEK emission rates increased with an increase in temperature, humidity, and ventilation rate. The mass transfer coefficients of MEK determined from the VOC emission model were approximately 0.00246 m/sec for those cases which used solvents and plasticizer, and decreased by a factor of 0.67 to 0.00164 m/sec for those cases which used solvents, plasticizer and PVC powder.     

Temperature and voltage sensings by mode‐mode interference in polarization‐maintaining optical fibers

Abstract

Two optic fiber sensing systems for temperature and voltage have been developed which utilize the mode‐mode interference of the two orthogonally polarized modes, HE^x _II and HE^y _II, in two commencal polarization‐maintaining fibers (bow‐tie and elliptical core fibers). A package of controlled programs in a Macintosh computer, which can record and process all related data automatically, is established for temperature sensing. The signal drifting problem in voltage sensings has been investigated, and the elimination of signal drifting is obtained by the phase tracking with direct current technology The agreement between the sensing results for temperature and dynamic voltage and those predicted by experimental principles is satisfactory, which confirms the validity of the developed sensing systems.     

Formation and rupture of Ag conductive bridge in ZrO2-based resistive switching memory

ZrO2-based resistive switching memory has attracted much attention according to its possible application in the next-generation nonvolatile memory. However, the resistive switching mechanism of the ZrO2-based memory device is still controversial. In this study, the mechanism of the ZrO2-based memory device is demonstrated that the resistive switching occurs because of the migration of Ag+ ions. While a positive voltage is applied, Ag+ ions in the ZrO2 film migrate to connect the Pt bottom electrode, causing the formation of Ag conductive bridge. On the other hand, while a negative voltage is applied, Ag+ ions migrate toward the Ag top electrode, leading to the rupture of the Ag conductive bridge. In addition, the resistive switching properties of the ZrO2-based memory device, such as switching voltages and non-destructive readout property, are also demonstrated in this study. Based on the experimental results, the ZrO2-based memory device with clear resistive switching mechanism can be possibly used in the next-generation nonvolatile memory.     

Multiaxial low cycle fatigue behavior and life prediction of CP-Ti under non-proportional stress-controlled mode

Multiaxial low cycle fatigue tests under non-proportional stress (NPSS) controlled mode were performed on commercial pure titanium (CP-Ti). Strain responses of axial and torsional channels under highly applied stress amplitudes show an initial hardening phenomenon. Non-proportional hardening coefficient of CP-Ti is independent of the controlled mode. The critical plane of CP-Ti under NPSS controlled mode is aligned with the maximum principal stress plane proved by optical microscopy observation. Optimized FSM model and KBM-PM model with mean axial and torsional strain are established. These models are further integrated into equations related to multiaxial stress ratio with high accuracy of life prediction for CP-Ti under NPSS controlled mode.     

Comparative studies on major nutritional components of black waxy rice with giant embryos and its rice bran

The concentration of nutrients in brown rice is mainly associated with embryo size. Various beneficial components have been purified from rice bran. Recently developed black waxy rice with a giant embryo (‘Milyang 263’, BGE), which is the ge ^t mutant of the GE gene, was selected and analyzed to produce high quality nutritional components. γ-Aminobutyric acid (GABA) content in BGE rice bran, one of the most important nutritional compounds in rice, showed a 10.6-fold increase (2.66±0.48 mg/g) compared to that of BGE brown rice (0.25±0.01 mg/g). In addition, brown rice and BGE rice bran showed enriched amylopectin (94.5±0.5 and 97.0±0.0%) and bioactive anthocyanin [Cy-3-G: 75.15±4.18 (brown rice), 82.97±0.81 (rice bran) and Pn-3-G: 1.52±0.50 (brown rice), 4.33±0.20 (rice bran); mg/100 g] contents. These results suggest that BGE rice bran can be used as an excellent raw material to efficiently produce high quality essential amino acids, cyanidin-3 glycoside-enriched anthocyanins, and GABA.     

马铃薯皮中绿原酸提取工艺优化

以马铃薯皮作为原料,对其所含有的抗氧化物质绿原酸进行提取工艺条件优化。采用乙醇回流法,以绿原酸得率为指标,考察料液比、乙醇体积分数、提取温度、回流次数对提取工艺条件的影响,采取正交试验确定最佳提取工艺条件。结果表明,马铃薯皮中绿原酸粗提的最佳工艺条件为料液比1∶10（g/mL）、乙醇体积分数85%、提取温度97 ℃、回流3 次,在最佳工艺条件下,绿原酸的得率为2.229 mg/g。体外抗氧化活性实验表明,绿原酸具有良好的抗氧化性。