The impact of physical performance and cognitive status on subsequent ADL disability in low-functioning older adults

We demonstrate that rectification ratios (RR) of ≳250 (≳1000) at biases of 0.5 V (1.2 V) are achievable at the two-molecule limit for donor–acceptor bilayers of pentacene on C₆₀ on Cu using scanning tunneling spectroscopy and microscopy. Using first-principles calculations, we show that the system behaves as a molecular Schottky diode with a tunneling transport mechanism from semiconducting pentacene to Cu-hybridized metallic C₆₀. Low-bias RRs vary by two orders-of-magnitude at the edge of these molecular heterojunctions due to increased Stark shifts and confinement effects

Chiral “Pinwheel” Heterojunctions Self-Assembled from C₆₀ and Pentacene

We demonstrate the self-assembly of C₆₀ and pentacene (Pn) molecules into acceptor–donor heterostructures which are well-ordered anddespite the high degree of symmetry of the constituent molecules<i>chiral</i>. Pn was deposited on Cu(111) to monolayer coverage, producing the random-tiling (<i>R</i>) phase as previously described. Atop <i>R</i>-phase Pn, postdeposited C₆₀ molecules cause rearrangement of the Pn molecules into domains based on chiral supramolecular “pinwheels”. These two molecules are the highest-symmetry achiral molecules so far observed to coalesce into chiral heterostructures. Also, the chiral pinwheels (composed of 1 C₆₀ and 6 Pn each) may share Pn molecules in different ways to produce structures with different lattice parameters and degree of chirality. High-resolution scanning tunneling microscopy results and knowledge of adsorption sites allow the determination of these structures to a high degree of confidence. The measurement of chiral angles identical to those predicted is a further demonstration of the accuracy of the models. van der Waals density functional theory calculations reveal that the Pn molecules around each C₆₀ are torsionally flexed around their long molecular axes and that there is charge transfer from C₆₀ to Pn in each pinwheel