High-performance, self-powered photodetectors based on vertically stacked van der Waals heterostructures toward bifacial photovoltaics
Er‐Xiong Ding, Anastasios Karakassides, Yaoqiang Zhou, Ruihuan Fang, Fida Ali, Esko I. Kauppinen, Zhipei Sun, Harri Lipsanen
Abstract
Self-powered photodetectors represent a transformative technology for next-generation wearable devices, particularly in environmental sensing and health monitoring applications. While significant progress has been made in this field, bifacial self-powered photodetectors utilizing vertically stacked van der Waals heterostructures remain largely unexplored. Here, we demonstrate an advancement in bifacial self-powered photodetectors through the innovative integration of a MoS 2 /WSe 2 heterostructure as the photosensitive medium with transparent indium tin oxide and single-walled carbon nanotube (SWCNT) film electrodes in a vertical architecture. These photodetectors exhibit exceptional photodetection capabilities, ultrafast response speeds, and remarkable stability. Operating in photovoltaic mode, the photodetector achieves a notable open-circuit voltage of 0.52 V and a power conversion efficiency of 3.89 %, positioning it among the top-performing 2D material-based photovoltaics reported to date. The exceptional bifacial functionality is evidenced by a near-unity bifacial factor of 98.5 %, demonstrating nearly equivalent power generation from both front and rear illumination. Furthermore, the photodetector delivers outstanding broadband photodetection performance across visible to near-infrared wavelengths, achieving a peak detectivity of 2.4 × 10 9 Jones under 840 nm laser illumination. This work not only establishes a scalable fabrication paradigm for wafer-scale flexible optoelectronics but also provides a fundamental framework for the development of advanced bifacial optoelectronics based on 2D materials. This work demonstrates a high-performance bifacial self-powered photodetector using a MoS 2 /WSe 2 van der Waals heterostructure with transparent electrodes, achieving a 98.5 % bifacial factor, 0.52 V open-circuit voltage, and 3.89 % efficiency, while enabling scalable fabrication for next-generation flexible optoelectronics. • MoS 2 /WSe 2 with transparent electrodes achieves a 98.5 % bifacial factor. • The photodetector shows 0.52 V open-circuit voltage and 3.89 % efficiency. • The detector offers broadband detection with peak detectivity of 1.5 × 10 12 Jones. • The work enables wafer-scale bifacial optoelectronics via CNT electrode.