Chemical Locking in Molecular Tunneling Junctions Enables Nonvolatile Memory with Large On–Off Ratios. Issue 15 (5th February 2019)

• Record Type: Journal Article
• Authors: Kumar, Sumit; Merelli, Michele; Danowski, Wojciech; Rudolf, Petra; Feringa, Ben L.; Chiechi, Ryan C.
• Is Part Of: Advanced materials. Volume 31:Issue 15(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-02-05
• Subjects: EGaIn -- memory -- molecular electronics -- spiropyran -- switching; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201807831
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: This paper describes the reversible chemical locking of sypiropyran switches bound to metallic surfaces to enable the encoding of nonvolatile information. Data are encoded spatially by selectively locking the spiropyran moieties in their merocyanine form using a combination of exposure to acid and UV light. Without exposure to acid, the merocyanine form spontaneously converts back to the spiropyran form. Bits are resolved by defining the regions of the monolayer that are exposed to acid, using a "soft punchcard" fabricated from a silicone elastomer. Information is read by measuring the tunneling charge–transport through the monolayer using eutectic Ga–In top‐contacts. The merocyanine form is more than three orders of magnitude more conductive than the spiropyran form, allowing the differentiation of bits. Photoelectron spectroscopy shows that the monolayers are undamaged by exposure to light, acid, base, and applied bias, enabling proof‐of‐concept devices in which an 8‐bit ASCII encoded six‐character string is written, erased, and rewritten. Abstract : Exposure to UV/visible light switches spiropyrans bound to gold electrodes between two conductance states that differ by three orders of magnitude in tunneling junctions. Selective treatment with acid locks the switches in the high‐conductance merocyanine state, enabling the reversible (re)writing of nonvolatile binary data that is encoded through the use of patterned microfluidic chambers and read using EGaIn electrodes.