Efficient organic photomemory with photography-ready programming speed

Abstract

We propose a device architecture for a transistor-type organic photomemory that can be programmed fast enough for use in electrical photography. Following the strategies used in a flash memory where an isolated charge storage node or floating gate is employed, the proposed organic photomemory adopts an isolated photo-absorption zone that is embedded between upper and lower insulator layers without directly interfacing with a semiconductor channel layer. This isolated photo-absorption zone then allows the device to operate in electrically ‘on’ state, in which the high electric-field region can have a maximal spatial overlap with the illuminated area for efficient and facile light-programming. With the proposed approach, a significant threshold voltage shift is attained even with the exposure time as short as 5 ms. High quality dielectric layers prepared by initiated chemical vapor deposition ensure erasing to occur only with electrical signal in a controlled manner. Retention time up to 700 s is demonstrated.

Robust Radical Cations of Hexabenzoperylene Exhibiting High Conductivity and Enabling an Organic Nonvolatile Optoelectronic Memory

“…Organic nonvolatile optoelectronic memories on the basis of organic field effect transistors (OFETs) have easy-to-integrate configuration and allow nondestructive reading and multibit storage within a single device , for applications in multilevel storage and flexible imaging circuits (photosensors). − To achieve bistable charge states that can be programed by photoirradiation for optoelectronic memory, it is usually necessary to equip OFETs with a floating gate, , a polymer electret, , or a photoswitchable molecule either in the semiconductor layer , or at the semiconductor–dielectric interface. , Herein, we demonstrate that the OFET of HBP-H can function as an organic nonvolatile optoelectronic memory without using a floating gate, an electret layer, or photochromic molecules because HBP-H is photochemically oxidized by molecular oxygen, leading to stable radical cations in the solid state. The on-state of this optoelectronic memory takes advantage of the persistent photoconductivity − of the organic phototransistor , of HBP-H, where molecular oxygen acts as deep traps for photogenerated electrons …”

Effect of Laser-Induced Direct Micropatterning on Polymer Optoelectronic Devices

“…Following a succession of technical advances, organic electronics have emerged as key optoelectronic device platforms. Organic light-emitting diodes (OLEDs), − organic photovoltaics (OPVs), and organic photosensors , have demonstrated their potentials toward various mainstream applications, including displays and solar cells, as well as niche applications like heart-monitoring sensors. , In addition, organic semiconductor-based devices have been utilized as key components in low-cost electronics (e.g., smart e-packaging and disposable electronic label). − However, the manufacturing cost for such applications is still not low enough for a wide usage of them in the market, and thus, cost-effective device fabrication methods are strongly desired. , While most commercialized organic devices, up to date, have been based on vacuum-evaporated small molecular thin films, solution-based polymer semiconductors are being studied as low-cost alternatives. ,, Unlike small molecular technologies, whose patterning can easily be achieved with a shadow masking, forming a pattern in solution-processed polymer semiconductor films is considered to be challenging. Inkjet printing or screen printing techniques can be employed in patterning of polymer films; however, forming an optimal formulation that can ensure both desired processability and good performance is not easily achieved. − In addition, the bank structures, which are required to keep the solution inside a given pattern, can also increase fabrication cost and complexity.…”

“…Following a succession of technical advances, organic electronics have emerged as key optoelectronic device platforms. Organic light-emitting diodes (OLEDs), 1−4 organic photovoltaics (OPVs), 5 and organic photosensors 6,7 have demonstrated their potentials toward various mainstream applications, including displays and solar cells, as well as niche applications like heart-monitoring sensors. 8,9 In addition, organic semiconductor-based devices have been utilized as key components in low-cost electronics (e.g., smart e-packaging and disposable electronic label).…”