Flexible High-Performance Photovoltaic Devices based on 2D MoS2 Diodes with Geometrically Asymmetric Contact Areas

Optoelectronic performance of 2D transition metal dichalcogenides (TMDs)-based solar cells and self-powered photodetectors remain limited due to fabrication challenges, such as difficulty in doping TMDs to form p-n junctions. Herein, MoS2 diodes based on geometrically asymmetric contact areas are shown to achieve a high current rectification ratio of approximate to 10(5), facilitating efficient photovoltaic charge collection. Under solar illumination, the device demonstrates a high open-circuit voltage (V-oc) of 430 mV and a short-circuit current density (J(sc)) of -13.42 mA cm(-2), resulting in a high photovoltaic power conversion efficiency (PCE) of 3.16%, the highest reported for a lateral 2D solar cell. The diodes also show a high photoresponsivity of 490.3 mA W-1, and a large photo detectivity of 4.05 x 10(10) Jones, along with a fast response time of 0.8 ms under 450 nm wavelength at zero bias for self-powered photodetection applications. The device transferred on a flexible substrate shows a high photocurrent and PCE retentions of 94.4%, and 88.2% after 5000 bending cycles at a bending radius of 1.5 cm, respectively, demonstrating robustness for flexible optoelectronic applications. The simple fabrication process, superior photovoltaic properties, and high flexibility suggests that the geometrically asymmetric MoS2 device architecture is an excellent candidate for flexible photovoltaic and optoelectronic applications.