Photochromic Diarylethenes Designed for Surface Deposition: From Self‐Assembled Monolayers to Single Molecules

Abstract

The efficient switching that can occur between two stable isomers of diarylethenes makes them particularly promising targets for opto‐ and molecular electronics. To examine these classes of molecules for electronics applications, they have been subjected to a series of scanning tunneling microscopy (STM) experiments, which are the focus of this Review. A brief introduction to the chemical design of diarylethenes in terms of their switching capabilities along with the basics of STM are presented. Next, initial STM studies on these compounds under ambient conditions are discussed. An overview of how molecular design affects the isomerization and self‐assembly of diarylethenes at the solid‐liquid interface as investigated by STM is then presented, as well as single‐molecule studies under ultrahigh vacuum. The last section presents further prospects for molecular design in the field.

Dynamically Controlled Electronic Behavior of Stimuli‐Responsive Materials: Exploring Dimensionality and Connectivity

“…Photochromic molecules have also been applied as a "switch" for property modulation of self-assembled monolayers (SAMs). [98][99][100][101][102][103] The SAMs were formed on Au-stripped substrates using a spiropyran derivative, H 2 SPDT (H 2 SPDT = 2-(3′,3′-dimethyl-6-nitrospiro[chromene-2,2′-indolin]-1′-yl)ethyl 6,8-dimercaptooctanoate; c = 1; Figure 11), through immersing the Au surface in an ethanol solution of H 2 SPDT. [96] The thickness of the resulting photochromic SAM was estimated to be 15.4 ± 2 Å, and quantitative analysis using XPS suggested that 38% of the spiropyran molecules undergo photoisomerization to merocyanine.…”

Visualization and Comprehension of Electronic and Topographic Contrasts on Cooperatively Switched Diarylethene-Bridged Ditopic Ligand

“…A photochromic molecule adsorbs light at specific wavelengths and thus appears with convertible colors [2,5]. Concomitant with color changes, their physical and chemical properties, such as molecular geometry, dipole moment and electronic structure, alter with isomerization and show switchable on and off states [5][6][7]. The interest in photoswitchable molecules is large and covers diverse research fields ranging from nanomachines (rotaxane-based molecular machines [8][9][10], light-driven rotary molecular motors [11,12]), photoactive nanoparticles (noble metal Nps [13][14][15], fluorescent Nps [16,17]), nanoelectronics [7] (photoactive molecular junctions [18][19][20][21][22], rectifiers [23], memories [24,25] or organic field effect transistors [25,26]), metal organic nanoassemblies (photoswitchable metal-organic molecular cage [27] or metal-organic frameworks [28,29]), supramolecular self-assembled systems (light-driven supramolecular amphiphiles [30], supramolecular polymers [31,32]), biological nanosystems [5,33] and pharmacology [34].…”

Visualization and Comprehension of Electronic and Topographic Contrasts on Cooperatively Switched Diarylethene-Bridged Ditopic Ligand

“…A photochromic molecule adsorbs light at specific wave-lengths and thus appears with convertible colors [2,5]. Concomitant with color changes, their physical and chemical properties, such as molecular geometry, dipole moment and electronic structure, alter with isomerization and show switchable on and off states [5][6][7]. The interest in photo-switchable molecules is large and covers diverse research fields ranging from nanomachines (rotaxane-based molecular machines [8][9][10], light-driven rotary molecular motors [11,12]), photoactive nanoparticles (noble metal Nps [13][14][15], fluorescent Nps [16,17]), nanoelectronics [7] (photoactive molecular junctions [18][19][20][21][22], rectifiers [23], memories [24,25] or organic field effect transistors [25,26]), metal organic nanoassemblies (photoswitchable metal-organic molecular cage [27] or metal-organic frameworks [28,29]) supramolecular self-assembled systems (light driven supramolecular amphiphiles [30], supramolecular polymers [31,32]), biological nanosystems [5,33] and pharmacology [34].…”