Asymmetric Charge Injection Barrier Yields High Rectification in Rhenium(I)-Organometallic Compound

Abstract

Electrical rectification is an important electronic function of semiconductor diodes. In electrical current rectification, many organic molecules and metal complexes have been explored, followed by understanding charge transport mechanisms. However, Re(I)-organometallic compounds hold many opportunities in electronic functions that have not been explored in electronic circuitry. This study focuses on emulating electrical current rectification by π-stacked rhenium(I) organometallic compounds embedded between p-doped Si and indium tin oxide electrodes in a two-terminal junction configuration. Among the tested compounds, viz. [Re(CO)4(PPh3){κ1-(N)-saccharinate}] (1) and [Re(CO)3(κ2-phen){κ1-(N)-saccharinate}] (2), the latter demonstrates a remarkable electrical current rectification ratio of ~ 4×103 at ± 2.0 V at room temperature. The device, composed of 2, shows proficient alternating current (AC) to direct current (DC) conversion at a frequency of up to 1 KHz, tested in a half-wave rectifier configuration. Temperature-dependent experimental current-voltage analysis implies the primary role of activated long-distance hopping for the charge transport and the asymmetric charge injection barrier heights at both electrode interfaces for current rectification. The above results lay the groundwork for using diverse organometallic compounds as circuit elements in nanoelectronic devices for specific electronic functions.