Two-dimensional transition metal dichalcogenides offer unprecedented opportunities for quantum photonics through strain-mediated exciton engineering. However, the paradoxical coexistence of strain-gradient-driven exciton funneling and efficient trion formation has remained unresolved. Here, we address this challenge by demonstrating that multistrain domains enable room-temperature exciton-trion interconversion in strain-engineered ${\mathrm{MoSe}}_2$ monolayers. This interconversion is most likely driven by flexoelectric fields arising from interfacial strain gradients. Using a thermal strain-modulated chemical vapor deposition approach, we have engineered interfacial strain gradients ($\sim 2.0\%\mu {\mathrm{m}}^{-1}$) that induce flexoelectric polarization, generating symmetry-broken quantum wells and driving near-unity quantum yield exciton-trion interconversion at room temperature. Crucially, through multimodal characterization techniques, we have unraveled the long-standing paradox in exciton dynamics under heterogeneous strain fields. Our findings demonstrate that the flexoelectric field likely plays a decisive role in decoupling electron-hole pair dynamics while maintaining charge neutrality—a critical mechanism mediated through electric effects rather than direct strain influences. This breakthrough significantly bridges the gap between two apparent contradictions in quantum phenomena: the competing processes of exciton funneling and trion formation observed in strained semiconductor systems. Further, by validating this model in flower-shaped samples with alternating curvature-induced field gradients, we establish a unified framework for deterministic exciton engineering. Our work provides fundamental insights into strain-mediated excitonics and enables scalable quantum photonic architecture through deterministic strain engineering.

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• Excitons
• Trions
• Flexoelectrics
• Atomic force microscopy
• Chemical vapor deposition
• Photoluminescence