Ultrafast Charge Transfer 2D MoS 2 /Organic Heterojunction for Sensitive Photodetector.

The 2D MoS 2 with superior optoelectronic properties such as high charge mobility and broadband photoresponse has attracted broad research interests in photodetectors (PD). However, due to the atomic thin layer of 2D MoS 2 , its pure photodetectors usually suffer from inevitable drawbacks such as large dark current, and intrinsically slow response time. Herein, a new organic material BTP-4F with high mobility is successfully stacked with 2D MoS 2 film to form an integrated 2D MoS 2 /organic P-N heterojunction, facilitating efficient charge transfer as well as significantly suppressed dark current. As a result, the as-obtained 2D MoS 2 /organic (PD) has exhibited excellent response and fast response time of 332/274 µs. The analysis validated photogenerated electron transition from this monolayer MoS 2 to subsequent BTP-4F film, whereas the transited electron is originated from the A - exciton of 2D MoS 2 by temperature-dependent photoluminescent analysis. The ultrafast charge transfer time of ≈0.24 ps measured by time-resolved transient absorption spectrum is beneficial for efficient electron-hole pair separation, greatly contributing to the obtained fast photoresponse time of 332/274 µs. This work can open a promising window to acquire low-cost and high-speed (PD).