Page 6 - Molecules for Charge-Based Information Storage

Molecules for Charge-Based Information Storage Lindsey and Bocian

FIGURE 5. Tethers (linkers and surface attachment groups).

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integrity is maintained at temperatures where most organic 1.8 10 , 1.1 10 , and 1.0 10 10 oxidation/reduction
molecules (e.g., ferrocene) decompose. Similar high-tem- cycles. During the experiment, the nature of the electrical
perature stability has been observed for a variety of por- cycling was varied. On some days, the system was continu-
phyrin architectures tethered to silicon, including a triple- ously cycled for 24 h. On others, cycling was stopped
decker complex. intentionally for periods ranging from a few minutes up to
The robustness of the porphyrin information-storage 12 h. The data indicate that after an initial “burn-in” period of
medium was further examined by repeatedly performing ∼10 7 cycles, the voltammetric response stabilizes. This
the cycle of (1) oxidizing the electrically neutral monolayer robustness of the system is further illustrated in Figure 6b
and (2) reducing the resulting positively charged monolayer wherein the integrated voltammetric signal (corresponding
to its electrically neutral state. 25 The five voltammograms in to the charge in the monolayer) is plotted as a function of the
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Figure 6a show the response of the system after 0, 2.5 10 , number of cycles. These data indicate that the charge-storage

Vol. 44, No. 8 ’ 2011 ’ 638–650 ’ ACCOUNTS OF CHEMICAL RESEARCH ’ 643