Xinhong Zhou

The allomorphism of a photochromic diarylethene

Abstract The photochromic diarylethene, 1,2-bis(2-methyl-5-(2,2′-dicyanovinyl)-thien-3-yl)perfluorocyclopentene ( 1a ), was synthesized by a novel method. Two kinds of single crystals of the compound were obtained depending on the different recrystallization conditions and their structures were determined by X-ray crystallographic analysis. Allomorphism of the photochromic diarylethene was discovered. The compound underwent a photochromic reaction both in solution and in the single crystalline phase of the anti-parallel conformer.

Efficient synthesis and photochromic properties of 2,3-position hybrid diarylethene derivatives

Abstract An efficient synthetic method was proposed to synthesize some 2,3-position hybrid diarylethene derivatives. In these compounds, one of thiophene rings was attached to the ethylene moiety at 2-position, the other at 3-position. These asymmetric diarylethenes are sensitive at wavelengths in the region of 400 and 500 nm. They can undergo thermally irreversible and fatigue-resistant photochromic reactions in solution, some of them even in the solid state. Substituent effects on their photochromism were examined.

Diarylethene materials for photon-mode optical storage

Photon-mode recording of photochromic materials is regarded as a promising storage system, which has various advantages over the traditional heat-mode recording in terms of its data capacity and data-recording rate. Diarylethenes show good thermal stability and remarkable fatigue resistance, and these properties are indispensable for the applications to optical storage materials. In present work, several diarylethene compounds were synthesized, and a series of optical storage tests were carried out on the sample discs with diarylethenes as the recording materials. The recording based on these photochromic materials was photon-type,and the recorded regions appeared as faded dots. 780, 650 and 532 nm lasers were used for writing on the corresponding discs, and the recorded information were readout by the same lasers respectively. A two-wavelength optical storage was realized on a mixed diarylethene recording layer by two laser beams of 532 nm and 650 nm synchronously. A higher data capacity can thus be expected to reach by using a multi-wavelength optical storage like that. Although the diarylethenes satisfy the minimum demands of optical storage systems, these molecules have one unsolved drawback: the lack of a non-destructive capability. In this work, Electric-locked properties were investigated in a BT3FP-OH thin film; the electric trigger could prevent the photochromic reactions, which provided a practicable non-destructive readout method. Three kinds of diarylethene derivatives linked by solvatochromic dye units wer fabricated; the theoretical investigation showed that reading at the wavelength of about 650-750 nm would destroy the recorded information no longer. Thus a non-destructive method could be constructed on these diarylethene molecules.

Synthesis and multiwavelength optical recording properties of two new photochromic diarylethenes

1,2-bis(2-methyl-5-(2-(1,3-dioxolane))-thien-3-yl)perfluorocyclopentene (1a) and 1,2-bis(2-methyl-5- 4-N,N-dimethyl-phenyl)-thien-3-yl)perfluorocyclopentene (2a) were synthesized and rewritable photo-mode muti-wavelength optical recording by the use of them was performed successfully. In amorphous film photochromic media, two laser beams of 532 nm and 650 nm were used in recording and readout simultaneously, and signals with high S/N ratio were detected. The results show that the reflectivity difference between the recorded dot and unrecorded region is greater than 50%, and above all, there is no crosstalk existing in the two diarylethenes, which it is very important to implement successfully multi-wavelength optical recording. The photochromic properties of them were also discussed.

Multiwavelength optical storage of diarylethene PMMA films

Current applied optical storage technologies are all based on the heat effect of the recording laser, i.e., heat-mode optical storage. In the present work, photon-mode optical storage using photochromic diarylethene materials was investigated. Two diarylethene molecules dispersed into PMMA together was used as storage material. The recording layer was spin-coated on a glass substrate with Al reflective layer. Two laser beams of 532 nm and 650 nm were used in recording and readout by simultaneously writing and reading, and the reading lasers detected signals with high S/N ratio. Multi-wavelength storage was realized with the diarylethene PMMA film.

Electrochromism of photochromic diarylethene derivative

The diarylethene may undergo photochemical ring-closing reaction and both photochemical and electrochemical ring-opening reaction. Irradiation of the open form with UV light results in essentially quantitative photocyclization to the deeply colored form. The dithienylcyclopentene derivative in their ring-closed forms can undergo ring-opening upon electrochemical oxidation.

Studies of organic photonic high-density read-only memory (OP-ROM)

Although recordable disk are rapidly developing, the mainstream in the market is still the read-only manufactures such as CD-ROM and DVD-ROM which have prerecorded information. How to enhance the storage density of read only memory is one of the hotspots in optical data storage. The authors put forward novel theory for read only memory. The novel theory takes little organic molecule as memory medium of read only memory, and the writing process is photon-mode, which is called organic photonic read only memory (OP-ROM). According to the novel theory, disks can be massively copied by exposure. Furthermore, because of diversity and modifiability of organic molecules, the storage density can be improved by multi-wavelength, multi-level and multi-layer.

Diarylethene-based photochromic rewritable optical storage media for short-wavelength recording

Two non-symmetric perfluorocyclopentene derivatives have been synthesized. The absorption bands of their closed forms are located at 400 to approximately 500 nm wavelength regions. They undergo thermally irreversible photochromic reaction and fatigue resistant. The closed-ring form remains thermally stable after several months. And the repeatable cycle number in hexane is more than 103 times in the presence of air. It demonstrates that they are promising candidates for short wavelength recording.

Synthesis and photochromic properties of diarylethene derivatives

Four photochromic diarylethenes with different spectra in open and closed form were synthesized simultaneously. Irradiation of the open form with UV light results in essentially quantitative photocyclization to the closed form. The compounds show attractive optical properties and are expected to be used in optical storage and photoswitch.

Synthesis and photochromic properties of asymmetric diarylethenes

Two asymmetric photochromic diarylethenes with different spectra in open and closed form were synthesized simultaneously. Irradiation of the open form with UV light results in essentially quantitative photocyclization to the deeply colored form. The compounds show attractive optical properties and are expected to be used in optical storage and photoswitch.