Thin‐film photovoltaics based on alkylammonium lead iodide perovskite light absorbers have recently emerged as a promising low‐cost solar energy harvesting technology. To date, the perovskite layer ...in these efficient solar cells has generally been fabricated by either vapor deposition or a two‐step sequential deposition process. We report that flat, uniform thin films of this material can be deposited by a one‐step, solvent‐induced, fast crystallization method involving spin‐coating of a DMF solution of CH3NH3PbI3 followed immediately by exposure to chlorobenzene to induce crystallization. Analysis of the devices and films revealed that the perovskite films consist of large crystalline grains with sizes up to microns. Planar heterojunction solar cells constructed with these solution‐processed thin films yielded an average power conversion efficiency of 13.9±0.7 % and a steady state efficiency of 13 % under standard AM 1.5 conditions.
Fast and thin: Flat, uniform thin films of CH3NH3PbI3 perovskites have been produced by a fast, one‐step procedure involving spin‐coating of a DMF solution of CH3NH3PbI3 and immediate exposure to chlorobenzene to induce crystallization. Planar heterojunction solar cells made with these films gave a maximum power conversion efficiency of 16.2 %.
Quercetin, a bioflavonoid derived from vegetables and fruits, exerts anti-inflammatory effects in various diseases. Our previous study revealed that quercetin could suppress the expression of matrix ...metalloprotease-9 (MMP-9) and intercellular adhesion molecule-1 (ICAM-1) to achieve anti-inflammatory effects in tumor necrosis factor-α (TNF-α)-stimulated human retinal pigment epithelial (ARPE-19) cells. The present study explored whether quercetin can inhibit the interleukin-1β (IL-1β)-induced production of inflammatory cytokines and chemokines in ARPE-19 cells. Prior to stimulation by IL-1β, ARPE-19 cells were pretreated with quercetin at various concentrations (2.5-20 µM). The results showed that quercetin could dose-dependently decrease the mRNA and protein levels of ICAM-1, IL-6, IL-8 and monocyte chemoattractant protein-1 (MCP-1). It also attenuated the adherence of the human monocytic leukemia cell line THP-1 to IL-1β-stimulated ARPE-19 cells. We also demonstrated that quercetin inhibited signaling pathways related to the inflammatory process, including phosphorylation of mitogen-activated protein kinases (MAPKs), inhibitor of nuclear factor κ-B kinase (IKK)α/β, c-Jun, cAMP response element-binding protein (CREB), activating transcription factor 2 (ATF2) and nuclear factor (NF)-κB p65, and blocked the translocation of NF-κB p65 into the nucleus. Furthermore, MAPK inhibitors including an extracellular signal-regulated kinase (ERK) 1/2 inhibitor (U0126), a p38 inhibitor (SB202190) and a c-Jun N-terminal kinase (JNK) inhibitor (SP600125) decreased the expression of soluble ICAM-1 (sICAM-1), but not ICAM-1. U0126 and SB202190 could inhibit the expression of IL-6, IL-8 and MCP-1, but SP600125 could not. An NF-κB inhibitor (Bay 11-7082) also reduced the expression of ICAM-1, sICAM-1, IL-6, IL-8 and MCP-1. Taken together, these results provide evidence that quercetin protects ARPE-19 cells from the IL-1β-stimulated increase in ICAM-1, sICAM-1, IL-6, IL-8 and MCP-1 production by blocking the activation of MAPK and NF-κB signaling pathways to ameliorate the inflammatory response.
The topology of the electronic structure of a crystal is manifested in its surface states. Recently, a distinct topological state has been proposed in metals or semimetals whose spin-orbit band ...structure features three-dimensional Dirac quasiparticles. We used angle-resolved photoemission spectroscopy to experimentally observe a pair of spin-polarized Fermi arc surface states on the surface of the Dirac semimetal Na3Bi at its native chemical potential. Our systematic results collectively identify a topological phase in a gapless material. The observed Fermi arc surface states open research frontiers in fundamental physics and possibly in spintronics.
This article presents the 38-GHz phased array 32-element Tx and 16-element Rx with 2-GHz IF and 5-GHz LO for fifth-generation (5G) millimeter-wave (MMW) communications. The Tx and Rx beamformers and ...upconverters/downconverters are fabricated in 65-nm CMOS. The PAs and LNAs near antenna ends are fabricated in 0.15-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> GaAs pHEMT. The eight-element Tx and four-element Rx phased array printed circuit board (PCB) modules integrated with multiple integrated circuits (ICs) and endfire antennas are implemented as unit cells. Four pieces of Tx modules are vertically stacked to construct an <inline-formula> <tex-math notation="LaTeX">8\times {4} </tex-math></inline-formula> brick array (planar array), while four Rx modules are to construct a <inline-formula> <tex-math notation="LaTeX">4\times {4} </tex-math></inline-formula> array. According to 38-GHz over-the-air (OTA) measurements, the 32-element Tx shows 47.5-dBm equivalent isotropic radiated power (EIRP) at OP<inline-formula> <tex-math notation="LaTeX">_{\mathrm {1 ~dB}} </tex-math></inline-formula> with −35.2-dB image rejection ratio (IMRR) and −37.4-dB <inline-formula> <tex-math notation="LaTeX">\times 8 </tex-math></inline-formula> LORR. The 16-element Rx at 38 GHz shows −4-dBm OP<inline-formula> <tex-math notation="LaTeX">_{\mathrm {1~dB}} </tex-math></inline-formula> with −28-dB IMRR and −36.6-dB LORR. The Tx and Rx support the beam scanning around ±60° azimuth and ±30° elevation planes. The Tx-to-Rx wireless data link demonstrates 64 quadrature amplitude modulation (QAM)/400 M-BR, 256 QAM/200 M-BR, and 512 QAM/100 M-BR in 20 m. To the best of our knowledge, this work is the first 5G 37-/39-GHz phased array Tx/Rx using the scalable brick array configuration and demonstrating competitive performances compared with previous works.
Mesoporous anatase TiO2 beads with high surface areas and controllable pore sizes are prepared by using a combined sol–gel and solvothermal process. Dye‐sensitized solar cells made from these ...mesoporous beads gave a total power conversion efficiency of 7.20% under AM 1.5 sunlight, higher than that obtained using Degussa P25 films of similar thickness (5.66%).
Hesperidin (HD) is a common flavanone glycoside isolated from citrus fruits and possesses great potential for cardiovascular protection. Hesperetin (HT) is an aglycone metabolite of HD with high ...bioavailability. Through the docking simulation, HD and HT have shown their potential to bind to two cellular proteins: transmembrane serine protease 2 (TMPRSS2) and angiotensin-converting enzyme 2 (ACE2), which are required for the cellular entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our results further found that HT and HD suppressed the infection of VeroE6 cells using lentiviral-based pseudo-particles with wild types and variants of SARS-CoV-2 with spike (S) proteins, by blocking the interaction between the S protein and cellular receptor ACE2 and reducing ACE2 and TMPRSS2 expression. In summary, hesperidin is a potential TMPRSS2 inhibitor for the reduction of the SARS-CoV-2 infection.
In this research, we proposed a highly tunable hybrid plasmonic biosensor for identifying molecule fingerprints of proteins in the infrared range. The device is composed of a photonic band-gap ...structure and a cavity. The plasmonic energy is confined inside the cavity to enhance the light-analyte interactions. A layer of graphene is placed on the bottom surface of the cavity that is filled with analytes for detection. Our device has a high value of effective sensitivity that is defined as the ratio of the resonant frequency shift to the change of effective refractive index when the cavity is loaded with an analyte. The effective refractive index takes into account the effects of both the cavity structure and the optical property of the analyte. Another feature of our device is that a wide-ranging electrical tunability can be realized by applying various values of bias voltage to the graphene. The resonant frequency can be tuned for sensing different analytes without redesigning and refabricating the device. In addition, the graphene tunability can improve the sensitivity in detecting the non-targeted analytes. A prototype was designed based on photonic theory and fabricated via bottom-up lithography techniques. The research results are expected to be beneficial for nanometer-range bio-identifications and infrared optical sensors.
Perovskite solar cells (PSCs) based on SnO2 electron transport layers have attracted extensive research due to their compelling photovoltaic performance. Herein, we presented an in situ passivation ...of SnO2 with low‐cost hydroxyacid potassium synergist during deposition to optimize the interface carrier extraction and transport for high power conversion efficiency (PCE) and stabilities of PSCs. The orbital overlap of the carboxyl oxygen with the Sn atom alongwith the homogenous nano‐particle deposition effectively suppresses the interfacial defects and releases the internal residual strains in the perovskite. Accordingly, a PCE of 24.91 % with a fill factor (FF) up to 0.852 is obtained for in situ passivated devices, which is one of the highest values for SnO2‐based PSCs. Moreover, the unencapsulated device maintained 80 % of its initial PCE at 80 °C over 600 h, 100 % PCE at ambient conditions for 1300 h, and 98 % after one week maximum power point tracking (MPPT) under continuous AM1.5G illumination.
The researchers developed a novel in situ passivation of SnO2 with optimized SnO2/perovskite interfacial carrier extraction and transport for efficient and stable perovskite solar cells (PSCs). A champion power conversion efficiency (PCE) of 24.91 % and a champion fill factor (FF) up to 0.852 were obtained.
This paper presents a novel design of compact dualpolarized multi-input and multi-output (MIMO) antennas with endfire radiation for millimeter-wave wireless applications. The low-cost printed circuit ...board process serves as the basis for the design, fabrication, and measurement of the proposed dualpolarized quasi Yagi-Uda antennas. Addressing the potential antenna locations in a mobile terminal, this paper investigates both the corner and the lateral design of antenna modules. Each design incorporates dual-port dual-polarized antennas co-located in a compact area. The lateral design is further extended to a linear 1×4 array for high-gain and phased-scanning operation. Experimental results show that the proposed compact dual-polarized quasi Yagi-Uda antennas are very suitable for MIM terminals of next-generation (5G) mobile communications.
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