Although it has been clearly elucidated that the change in the overall bulk-heterojunction (BHJ) morphology of PM6:Y6 induced by the difference in solvents results in a variation in the performance of the entire solar cell, the charge dynamics during the charge separation process induced by morphological changes have not yet been deeply studied. Based on mobility and photocurrent-related studies, it has been inferred that holes are deeply involved in these charge generation and separation processes. The decrease in exciton dissociation probability observed in the PM6:Y6 solar cell fabricated using CB (PM6:Y6-CB) was found to be due to the change in the hole transfer state caused by morphological changes. For the PM6:Y6 solar cell fabricated using CF (PM6:Y6-CF), it was determined that the density of the state (DOS) of the effective hole transfer state (hECT) was small, as hECT and Y6 HOMO were almost degenerate, and the lower hECT, which can interfere with hole transfer, was also formed minimally. However, for PM6:Y6-CB, the overlapping region of hECT and the highest occupied molecular orbital (HOMO) of Y6 shifted towards the lower energy side (upper hECT), and a lower effective hECT that can act as a defect was significantly formed. These facts obtained by EL deconvolution were clearly confirmed in time-resolved photoinduced absorption spectroscopy. As a result, it is concluded that the decrease in fill factor (FF) and current density (JSC) in PM6:Y6-CB is due to the degradation of hole transfer from Y6 HOMO to PM6 HOMO. This analysis shows that the morphological changes in non-fullerene acceptor (NFA) solar cells affect the formation of hole transfer levels, which in turn affect the charge separation efficiency.
Thus far, there have been tries of detection of disease using fluorescent materials. We introduce the chlorophyll derivatives from food plants, which have longer-wavelength emissions (at >650 nm) than those of fluorescence of tissues and organs, for detection of bowel perforation. To figure out the possibility of fluorescence spectroscopy as a monitoring sensor of bowel perforation, fluorescence from organs of rodent models, intestinal and peritoneal fluids of rodent models and human were analyzed. In IVIS fluorescence image of rodent abdominal organ, visualization of perforated area only was possible when threshold of image is extremely finely controlled. Generally, both perforated area of bowel and normal bowel which filled with large amount of chlorophyll derivatives were visualized with fluorescence. The fluorescence from chlorophyll derivatives penetrated through the normal bowel wall makes difficult to distinguish perforation area from normal bowel with direct visualization of fluorescence. However, intestinal fluids containing chlorophyll derivatives from food contents can leak from perforation sites in situation of bowel perforation. It may show brighter and longer-wavelength regime emissions of chlorophyll derivatives than those of pure peritoneal fluid or bioorgans. Peritoneal fluid mixed with intestinal fluids show much brighter emissions in longer wavelength (at>650 nm) than those of pure peritoneal fluid. In addition, irrigation fluid, which is used for the cleansing of organ and peritoneal cavity, made of mixed intestinal and peritoneal fluid diluted with physiologic saline also can be monitored bowel perforation during surgery.
We have detected the surface-enhanced Raman scattering (SERS) signals of toluene and 1,2-dichlorobenzene (ODCB) vapors at parts per million concentrations using 1-propanethiol-linked Ag nanoparticles and a fiber optics–coupled Raman spectrograph. Calibration curves were constructed for each detector by plotting Raman band intensity ratios of toluene and ODCB with respect to that of 1-propanethiol as a function of vapor concentration. The detectors showed effective vapor sensing ranges of 0.6 to 600 and 10 to 600 ppm for toluene and ODCB, respectively, following vapor adsorption to the SERS hot spots. We provide evidence for the facility of the SERS detection system for instantaneously discriminating and quantifying respective vapors from a composite vapor.
Recent progress in modified Surface Enhanced Raman Scattering (SERS) using Ag nanoparticles makes them promising optical technique for direct gas sensing of interest. However, SERS has been shown to provide sub ppb level detection of the compounds in the vapor phase. The major problem with the sensitivity scaling-up was in the development of fabrication technology for stability and reproducibility of SERS substrates. We report an optimization of 1-propanethiol coated multiple Ag nanoparticle layers on SiO2 substrate as well as new records of real-time, simultaneous vapor phase detection of toluene and 1-2 dichlorobenzene by the radiation of fiber optic coupled 785 nm diode laser and spectrograph. Multiple depositions of Ag NPs were loaded on SiO2 and soaked in 1-propanethiol solution for 24 hours to modify the surface into hydrophobic due to the characteristics of vapor phase of our interests. Raman bands at 1003 cm-1 and 1130 cm-1 for toluene and 12DCB, respectively were compared to 1089 cm-1 and each gas concentration in 1000 mL flask were calculated as a function of each vapor phase ratio. The saturation of toluene and 12DCB were limited only by 800 ppm and the detectable range was 0.6-800 ppm.
The carrier concentration injected from a silicon substrate to a copper phthalocyanine thin film was found to depend on the incidence polarization of the photoexciting beam. The modulation efficiency of terahertz transmission due to transverse-magnetic (TM)-polarized excitation is distinctly higher than that due to transverse-electric (TE)-polarized excitation. Underlying this difference is the enhancement of carrier injection when the TM-polarized light is more transmitted through the surface of organic thin films than the TE-polarization light.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.