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

Abstract 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 ≈10⁵, 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 × 10¹⁰ 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.