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The extraordinary properties of graphene have spurred huge interest in the experimental realization of a two-dimensional honeycomb lattice of silicon, namely, silicene. However, its synthesis on supporting substrates remains a challenging issue. Recently, strong doubts against the possibility of synthesizing silicene on metallic substrates have been brought forward because of the non-negligible interaction between silicon and metal atoms. To solve the growth problems, we directly deposited silicon on a chemically inert graphite substrate at room temperature. Based on atomic force microscopy, scanning tunneling microscopy, and ab initio molecular dynamics simulations, we reveal the growth of silicon nanosheets where the substrate-silicon interaction is minimized. Scanning tunneling microscopy measurements clearly display the atomically resolved unit cell and the small buckling of the silicene honeycomb structure. Similar to the carbon atoms in graphene, each of the silicon atoms has three nearest and six second nearest neighbors, thus demonstrating its dominant sp

Deoxyribonucleic acid (DNA) was successfully incorporated as a nanolayer between the bottom indium tin oxide (ITO) transparent electrode and the photoabsorbing film in a polymer solar cell. Upon film optimization and analyses with scanning tunneling spectroscopy/currents, we demonstrate that a 1–6 nm thick DNA stratum functions as an effective electron-extracting layer, leading to strong improvements in rectifying behavior (by 2 orders of magnitude with rectifying ratios reached larger than 103) and in photovoltaic parameters like the open-circuit voltage (VOC from 0.39 to 0.73 V) and power conversion efficiencies (PCEs from ∼2 to ∼5%). The results show that DNA is a very ductile nanomaterial for electronic purposes, paving the way for future exploration in photovoltaic devices combining its electron-extracting properties with its functional and self-assembly behavior. Furthermore, solar cell devices were completely processed at room temperature, and DNA was cast from ecofriendly solvents such as water an...