Covalent Functionalization of Black Phosphorus with Conjugated Polymer for Information Storage

Major disadvantages of black phosphorus (BP) are its poor air-stability and poor solubility in common organic solvents. The best way to solve this problem is to incorporate BP into a polymer backbone or a polymer matrix to form novel functional materials that can provide both challenges and opportunities for new innovation in optoelectronic and photonic applications. As a proof-of concept application, we synthesized in situ the first highly soluble conjugated polymer-covalently functionalized BP derivative (PDDF-g-BP) which was used to fabricate a resistive random access memory (RRAM) device with a configuration of Au/PDDF-g-BP/ITO. In contrast to PDDF without memory effect, PDDF-g-BP-based device exhibits a nonvolatile rewritable memory performance, with a turn-on and turn-off voltages of +1.95 V and −2.34 V, and an ON/OFF current ratio of 10⁴. The current through the device in both the ON and OFF states is still kept unchanged even at 200th switching cycle. The PDDF/BP blends show a very unstable memory performance with a very small ON/OFF current ratio.