Spin injection and transport in single-crystalline organic spin valves based on TIPS-pentacene

Abstract

Single crystals of organic semiconductors with perfect crystal structure and minimal density of defects can exhibit high mobility and low spin scattering compared with their amorphous or polycrystalline counterparts. Therefore, these materials are promising candidates as the spin transport media to obtain long spin relaxation times and spin diffusion lengths in spintronic devices. However, the investigation of spin injection and transport properties in organic single crystals is hindered by the inability to construct devices such as single-crystalline organic spin valves (OSVs). Herein, thin and large organic single crystals of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) were grown on a liquid substrate and transferred to a target substrate carrying ferromagnetic electrodes to construct single-crystalline OSVs. The magnetoresistance (MR) responses of the single crystals were investigated to study their spin injection and transport properties. MR value as high as 17% was probed with an intermediate layer thickness of 269 nm. More importantly, spin transport was still observed in a single crystal of a thickness up to 457 nm, which was much larger than that of polycrystalline thin film. Our research provides a general methodology for constructing single-crystalline OSVs and paves the way to probe the intrinsic spin transport properties of organic semiconductors based on single crystals.

Recent Progress of Organic Semiconductor Materials in Spintronics

“…This work pointed out a model compound with a long spin diffusion length and promoted the development of single‐crystal spintronics. In 2021, Hu's group [20c] reported a spin valve (LSMO/TIPs‐pentacene/Co) based on 6,13‐bis(triisopropylsilylethynyl)pentacene single crystal. At 30 K, the MR signal of the single crystal with a thickness of 269 nm was as high as 17%, which was much above that of polycrystalline film and can still be measured in the single crystal with a thickness of 457 nm.…”

Manipulation of magneto-electroluminescence from exciplex-based spintronic organic light-emitting diodes

“…[1][2][3][4][5][6] This provides a high-sensitivity and low-cost electrical way to read and write signals in minimized magnetic memories and magnetic sensors. [5][6][7][8][9] In recent years, research interests also focused on the utilization of spin for photon manipulation to achieve spin-optoelectronic functions, including magneto-electroluminescence (MEL), magneto-photoluminescence (MPL) and spin-induced circularly polarized light. 3,[10][11][12][13] These novel functions exhibit appealing application potential in quantum communication, optical information processing, and three-dimensional (3D) displays due to its advantage in the simultaneous control of charge, spin and photons.…”

The prospects of organic semiconductor single crystals for spintronic applications

“…This is mainly because the weak v an der Waals forces between organic molecules in an OSSC 22 mean it shows poor thermal resistance, and it is easily damaged by the thermal energy and kinetic energy of metal atoms during the fabrication of the OSV. 55,56 At present, the FM materials are normally deposited via thermal evaporation, 57–60 e-beam evaporation, 53,54,61–64 and magnetron sputtering, 5,26,31,57–60 all of which possess very high thermal and kinetic energy. These high-energy preparation methods can cause the deconstruction and sublimation of the OSSC, as shown in Fig.…”