Highly Efficient Van Der Waals Heterojunction on Graphdiyne toward the High-Performance Photodetector

Graphdiyne (GDY), a new 2D material, has recently proven excellent performance in photodetector applications due to its direct bandgap and high mobility. Different from the zero-gap of graphene, these preeminent properties made GDY emerge as a rising star for solving the bottleneck of graphene-based inefficient heterojunction. Herein, a highly effective graphdiyne/molybdenum (GDY/MoS₂ ) type-II heterojunction in a charge separation is reported toward a high-performance photodetector. Characterized by robust electron repulsion of alkyne-rich skeleton, the GDY based junction facilitates the effective electron-hole pairs separation and transfer. This results in significant suppression of Auger recombination up to six times at the GDY/MoS₂ interface compared with the pristine materials owing to an ultrafast hot hole transfer from MoS₂ to GDY. GDY/MoS₂ device demonstrates notable photovoltaic behavior with a short-circuit current of -1.3 × 10^-5 A and a large open-circuit voltage of 0.23 V under visible irradiation. As a positive-charge-attracting magnet, under illumination, alkyne-rich framework induces positive photogating effect on the neighboring MoS₂ , further enhancing photocurrent. Consequently, the device exhibits broadband detection (453-1064 nm) with a maximum responsivity of 78.5 A W^-1 and a high speed of 50 µs. Results open up a new promising strategy using GDY toward effective junction for future optoelectronic applications.