Development of Field-Effect Transistor-Type Photorewritable Memory Using Photochromic Interface Layer

Abstract

We developed a novel field-effect transistor (FET) type photorewritable memory using a photochromic interface layer between the active layer and the gate insulator layer. A diarylethene (DAE) derivative was employed as a photochromic material and pentacene was employed as an active layer. DAE has two types of photoisomer, i.e., the closed- and open-ring isomers. In this study, it was clarified that the highest occupied molecular orbital (HOMO) level of the closed-ring DAE worked as an interfacial deep trap level, and that the generation of the interfacial deep trap level by photoisomerization induced the photoswitching and photomemory behaviors of transistor properties.

Optically switchable transistors by simple incorporation of photochromic systems into small-molecule semiconducting matrices

“…Similar to DAE_Me, it is possible that DAE_tBu does not interfere with the polycrystalline domains but locates in the amorphous regions of P3HT. Moreover, previous reports on combining another DAE derivative with a small molecule, such as pentacene, showed that the HOMO level of the ring-open isomer did not act as a trap level 11 , which is in agreement with our results for P3HT with DAEs. However, for -300 …”

“…However, thin films made solely from DAEs suffer from rather poor charge transport properties. This problem can be solved by blending the DAE with organic (semi)conductors such as carbon nanotubes 10 , pentacene 11 or poly(3-hexylthiophene) (P3HT) 12 to combine the light-responsive nature of the DAE with the advantageous charge transport characteristics of the respective matrix component. We have recently shown that by blending DAE and P3HT in solution-processed bi-component films, the P3HT forms polycrystalline structures, while the DAE is dispersed in the less aggregated regions of the polymer film 12 .…”

Optically switchable organic field-effect transistors based on photoresponsive gold nanoparticles blended with poly(3-hexylthiophene)

“…These features can be optimized by achieving control over the packing of SAMs on the NPs (7). When NPs are integrated in a device, they can, for example, act as charge storage sites-i.e., trapping charges centers, allowing the system to act as a memory (9, 10).The incorporation of photochromic molecules into electronic devices to confer them a photoresponsive nature has been recently explored (11)(12)(13)(14). Among photochromic systems (15-18), azobenzene derivatives are known to undergo isomerization from trans to cis form, and vice versa, under illumination at a specific wavelength, as well as from cis to trans with temperature (15).…”

“…The incorporation of photochromic molecules into electronic devices to confer them a photoresponsive nature has been recently explored (11)(12)(13)(14). Among photochromic systems (15)(16)(17)(18), azobenzene derivatives are known to undergo isomerization from trans to cis form, and vice versa, under illumination at a specific wavelength, as well as from cis to trans with temperature (15).…”

Towards Photo-Switchable Transport in Quantum Dot Solids

“…While carrier mobilities in these molecules have been found to be too low so far for an efficient application of the neat materials [4], promising device perspectives have been achieved upon doping high-mobility organic semiconductors with photo-switchable small molecules (PSMs). To name only a few, the ON/ OFF ratio of organic field-effect transistors can be optically tuned with PSMs at the metal contact or by direct mixing with the active semiconductor [5,6]; blending dielectric materials with PSMs has been used to optically modulate their gate capacitance [7] and even "photo-programmable" organic light-emitting diodes have been realized with PSM-doped hole injection layers [8].…”