A pioneering study by researchers of The Hong Kong Polytechnic University (PolyU) has shown that sandwiching a simple layer of silver nanoparticles can significantly improve the performance of organic transistors which are commonly used in consumer electronics. This revolutionary breakthrough is expected to cut down the cost of memory devices such as touchscreens and e-books and improve their performance. The novel method developed by PolyU researchers is much more compatible with the low-cost, continuous roll-to-roll fabrication techniques used to make organic electronics.
Dr Chan and his co-researchers have shown that the thickness of the nanoparticle layer changes the memory device performance in a more predictable way and thereby optimizing transistor performance to meet application requirements. Organic transistors made with a 1-nanometer nanoparticle layer have stable memory which lasts for three hours, making it suitable for memory buffers. And transistors with a 5-nanometer-thick layer can retain their charge for a much longer time.
We demonstrate the modification of the memory effect in organic memory devices by adjusting the thickness of silver nanoparticles (NPs) layer embedded into the organic semiconductor. The memory window widens with increasing Ag NPs layer thickness, a maximum window of 90 V is achieved for 5 nm Ag NPs and the on/off current ratio decreases from 10^5 to 10 when the Ag NPs layer thickness increases from 1 to 10 nm. We also compare the charge retention properties of the devices with different Ag NPs thicknesses. Our investigation presents a direct approach to optimize the performance of organic memory with the current structure.