Ligand-Triggered MXene Quantum Dots with Tunable Work Function as Anode and Cathode Interlayers for Organic Solar Cells

Abstract

The interfacial layers of organic optoelectronic devices generally suffer from the problems of difficulty in regulating the work function (WF) and low mobility, which are prone to mismatch of interfacial energy levels and loss of carrier transport energy. Herein, O-terminated and NH2-terminated Ti3C2Tx MXenes quantum dots (MQDs) are synthesized to develop efficient O-MQD hole transfer layer (HTL) and E-MQD electron transfer layer (ETL) for organic optoelectronic devices of organic solar cells (OSCs) and organic photodetectors (OPDs). It is found that the strong electronic coupling interaction between the surface terminations and matrices enables O-MQD and E-MQD with tunable WF and satisfactory conductivity. Consequently, in a binary D18:L8-BO system, the power conversion efficiencies of the OSC device based on O-MQD HTL and E-MQD ETL are 18.62% and 18.15%, respectively. Moreover, the OPDs with O-MQD HTL and E-MQD ETL exhibit higher shot-noise-limited detectivity (Dshot*) of 1.24 × 1013 and 1.10 × 1013 Jones, respectively, compared to the devices using classic interlayers. These findings provide some insights into the design of advanced dual-function interlayers for organic optoelectronic devices.