In organic photovoltaics (OPVs), determining the energy-level alignment of a donor and an acceptor is particularly important since the interfacial energy gap between the highest occupied molecular orbital (HOMO) level of a donor and the lowest unoccupied molecular orbital (LUMO) level of an acceptor (E-E) gives the theoretical maximum value of the open-circuit voltage (V). To increase the E-E, non-fullerene acceptors, which have a lower electron affinity (EA) than C, are receiving increasing attention. In this study, we investigated the energy-level alignment at the interface of a boron chloride subphthalocyanine (SubPc) donor and a halogenated SubPc (ClSubPc) acceptor using soft X-ray spectroscopy techniques. The estimated E-E of ClSubPc/SubPc was 1.95 eV, which was significantly higher than that of 1.51 eV found at the interface of C/SubPc. This increased E-E was the origin of the enhanced V in OPVs. Additionally, we studied the molecular orientation of ClSubPc using angle-dependent X-ray absorption spectroscopy. The highly disordered ClSubPc molecules result in low carrier mobility, which contributes to the lower short-circuit current density of the ClSubPc acceptor OPVs than the C acceptor OPVs.

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This study explored the effect of pulsed magnetic field (PMF) stimulus on the improvement of blood stagnation by means of photoplethysmography (PPG). Our stimulus system was designed to generate PMF with a maximum intensity variation of 0.20 T at a transition time of 160 µs, with pulse intervals of 1 Hz. In order to quantitatively estimate vascular condition, indices such as blood vessel tension (BVT), stress power (SP), differential pulse wave index (DPI) and remained blood volume (RBV) were calculated from the second derivative of the PPG signal and power density spectrum (PDS). Our results showed that non-invasive PMF stimulus was effective in improving blood stagnation. Therefore, it may be concluded that appropriate PMF stimulus affects the blood circulatory system.

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