Fig. 5 | Nature Communications

Fig. 5

From: On-surface light-induced generation of higher acenes and elucidation of their open-shell character

Fig. 5

Electronic structure of heptacene and nonacene. a, b Differential conductance spectra of heptacene (a) and nonacene (b); the blue curves were acquired at the corner position while the red curves were acquired at the apex of the molecule, as indicated in the constant-current STM images (a: V = 1 V, I = 40 pA, b: V = 2 V, I = 5 pA) in the inset. c, d Experimental constant-current differential conductance maps at the PIR and the NIR (left), and DFT simulations of the corresponding HOMO for the N + 1 and N − 1 electron system in gas phase (right) of heptacene (c) and nonacene (d). Current values: 40 pA (c, top), 80 pA (c, bottom), 60 pA (d, top), 90 pA (d, bottom). e Experimentally determined energy positions of the PIR and the NIR, respectively for acenes from pentacene to decacene on Au(111). Data points for pentacene36, hexacene35, octacene44 and decacene43 are taken from literature. f Experimental electronic gaps (black curve) together with computed quasiparticle energy gaps for the singlet open-shell (blue curve) and closed-shell (pink curve) configurations, including screening effects from the Au(111) substrate. Scale bars: a, b, c: 1 nm, d: 0.5 nm. Prior to recording the dI/dV spectra, tip heights were stabilized with the following set points: −1 V, 40 pA (a, blue curve), 1.5 V, 40 pA (a, red curve), −0.6 V, 60 pA (b, blue curve) and 1.2 V, 50 pA (b, red curve)

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