Iqbal Utama1,Hongfei Zeng1,Tumpa Sadhukhan1,Anushka Dasgupta1,S. Gavin1,Riddhi Ananth1,Dmitry Lebedev1,Wei Wang2,Jia-Shiang Chen2,Kenji Watanabe3,Takashi Taniguchi3,Tobin Marks1,Xuedan Ma2,Emily Weiss1,George Schatz1,Nathaniel Stern1,Mark Hersam1
Northwestern University1,Argonne National Laboratory2,National Institute for Materials Science3
Iqbal Utama1,Hongfei Zeng1,Tumpa Sadhukhan1,Anushka Dasgupta1,S. Gavin1,Riddhi Ananth1,Dmitry Lebedev1,Wei Wang2,Jia-Shiang Chen2,Kenji Watanabe3,Takashi Taniguchi3,Tobin Marks1,Xuedan Ma2,Emily Weiss1,George Schatz1,Nathaniel Stern1,Mark Hersam1
Northwestern University1,Argonne National Laboratory2,National Institute for Materials Science3
Two-dimensional (2D) materials such as monolayer WSe<sub>2</sub> have prospective applications in quantum information science because of their capability to host single-photon emitters (SPEs). However, chemical functionalization remains an unexplored parameter space in the design and control of SPEs based on 2D materials, whose atomically thin structure should yield strong tunability with interfacial modifications. Moreover, SPEs in 2D materials are typically generated using a single mechanism such as strain. Here, we report a chemomechanical approach to modify SPEs by using a synergistic combination of localized mechanical strain and non-covalent functionalization with aryl diazonium chemistry. Following a facile diazonium treatment, the dense defect-related emissive states of strained monolayer WSe<sub>2</sub> are simplified into spectrally-isolated SPEs with high photon purity. Our work significantly broadens the possibilities in the parameter space of designing 2D materials-based SPEs by utilizing molecular heterojunction and chemical functionalization approaches.