Strain gradient engineered flexophotovoltaics and spin polarization in bent <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>MoSi</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi mathvariant="normal">N

The authors demonstrate here that strain-gradient engineering in bent MoSi${}_{2}$N${}_{4}$ nanoribbons induces not only self-doping and a nonzero Berry curvature dipole, but also achieves an outstanding flexoelectric power conversion efficiency of 9.05%, the highest among 2D flexophotovoltaic systems. Under circularly polarized light, the bent MoSi${}_{2}$N${}_{4}$ photodetector generates a self-powered spin photocurrent. These results advance the fundamental understanding of mechanical-electronic coupling in 2D materials and highlight the potential of MoSi${}_{2}$N${}_{4}$ for high-efficiency solar cells, optoelectronics, and spintronic applications.