Interface Engineering for Enhancing Air-Stable Spin-Charge Interaction in Molecular Spin-Photovoltaic Devices

Molecular semiconductors (MSCs) are known as ideal candidates for constructing room-temperature spin-charge interactive devices due to their long spin lifetimes and abundant photoelectric properties. These devices can achieve novel and valuable functionalities such as room-temperature supply units of fully spin-polarized current. Unfortunately, their performances (sub-0.1 nA) remain unsatisfactory due to limited charge and spin injection efficiency, which can hardly be improved despite great efforts thus far. Herein, from the theoretical side, an interfacial tunnel layer with precisely-controlled barrier in spintronic devices may simultaneously enhance spin and charge injection. Accordingly, a solution-processed small molecule with smooth morphology and amorphous structure is introduced to form a uniform and well-controllable barrier in molecular spin-photovoltaic devices. By modulating the thickness to effectively control the barrier, both spin and charge injection efficiency increase by > 150%. Thus, the spin-charge interactive functionalities as supply units of fully spin-polarized current have also been significantly improved than the current record at room temperature, the output fully spin-polarized current (>2 nA) is 1200%-larger, and the output power increases by > 50 times. Moreover, the interface-modified spintronic devices exhibit excellent stability even after 70 days of exposure to air, which is essential for practical applications in the future.