Achieving Low Exciton-Exciton Annihilation Rates and High Exciton Diffusion Coefficients in Monolayer WS2 on Solid-State Electrolytes

Transition metal dichalcogenides (TMDCs) over solid-state electrolytes, such as Li-glass and LaF3, have demonstrated enhanced electronic and optoelectronic performance. However, a thorough understanding of exciton formation, recombination, and diffusion in TMDCs with solid electrolytes is still lacking. Here, we reported that monolayer WS2 over Li-glass and LaF3 showed a disorder-dominated exciton annihilation process and demonstrated annihilation rates of 0.033 and 0.023 cm2/s, respectively. Moreover, we found high diffusion coefficients of 278 and 88.9 cm2/s for Li-glass/WS2 and LaF3/WS2, respectively, accompanied by the formation of an exciton ring in Li-glass/WS2. We explored the factors influencing the rapid propagation of excitons and the formation of exciton rings, highlighting the significant role played by the electron-hole plasma induced by the electrical double layer at the interface. These results highlighted the crucial impact of interface disorders and electric field effects on exciton behavior in TMDCs over solid electrolytes.