Heterojunction-Based Hybrid Silicon Nanowires Solar Cell

It is known that defect-free, i.e., oxide-free, Si nanowires (Si NWs) exhibit lower defect density emissions than unmodified Si NWs. This is successfully established by grafting organic molecules on the surface. Here we show that by using a two-step chlorination/alkylation process, we are able to graft organic molecules on Si NWs for solar cell applications. Afterward, we show the electronic properties of the molecular surface (such as work function and band bending). Finally, we correlate these properties to the solar cell performance

Impact of exposing lithium metal to monocrystalline vertical silicon nanowires for lithium-ion microbatteries

Silicon has attracted considerable attention for use as high-capacity anodes of lithium-ion microbatteries. However, its extreme volume change upon (de-)lithiation still poses a challenge for adoption as it leads to severe active lithium loss that shortens the cycle life. Here, we fabricate three-dimensional monocrystalline vertical silicon nanowires on a silicon wafer using low-cost metal-assisted chemical etching, then cover them with lithium using thermal evaporation prior to the battery operation as the pre-lithiation step, to investigate its impact on electrochemical performance. To reveal the underlying physical and electrochemical mechanisms, we also process a comparative planar monocrystalline silicon. We find that pre-lithiation results in improved (de-)lithiation behavior, especially in planar silicon-based cells, while silicon nanowire-based cells exhibit low capacity in early cycles. This study sheds light on the surface design and structural modification of monocrystalline silicon nanowires with respect to pre-lithiation by lithium thermal evaporation

Specific and Label‐Free bioFET Sensing of the Interaction Between the Electrically Neutral Small Estriol Molecule and Its Antibody in a Microliter Drop of Diluted Plasma

Abstract The sensing of small molecules is important to a variety of fields and particularly to clinical diagnostics. Estriol is an important small chemical molecule, as it is one of three markers measured during mid‐gestation for the Down syndrome. Point‐of‐care testing of estriol will increase maternal compliance for aneuploidy mid‐gestation screening. A bioFET technology is a promising point‐of‐care platform. The meta‐nano‐channel (MNC) bioFET is employed with its tunable channel configuration to optimize the coupling between the electrostatics of the estriol‐receptor interactions and the electrodynamics of the conducting readout current. Also, the MNC bioFET receptor layer is composed of anti‐estriol antibodies to address the high structural similarity of estriol to other estrogens. Despite the small size and the electrical neutrality of estriol, real‐time is demonstrated, specific, and label‐free sensing of estriol in 0.5 µL of 1:100 diluted plasma with excellent linearity, sensitivity, dynamic range extending to ten orders of magnitude in estriol concentration and limit‐of‐detection of 1 fg mL−1. Extensive control and non‐specific measurements are reported including the response to other neutral members of the estrogen family