Organic solar cell (OSC), which is deemed to be the most promising third generation solar energy application, is developing vigorously. Based on the modified strain gradient theory (MSGT) and the refined shear deformation plate theory, static bending and free vibration of the size-dependent OSC are thoroughly investigated in this paper. A Winkler-Pasternak elastic foundation is considered for the OSC. A multiscale suitable plate analysis framework (i.e., both macro- and micro plates can be handled) is developed herein. Three length scale param-eters are incorporated in the presented analysis to capture the size-dependency of the OSC. By setting two or three of them into zero, the presented model could degenerate into the modified couple stress theory (MCST) and the classical plate theory (CPT). The derivation of the governing equations and the corresponding boundary conditions are conducted by Hamilton principle. The Navier-type solution is employed for solving the governing equations of the simply supported OSC. The accuracy of the presented method is validated. Extensive numerical experiments have been conducted to investigate the differences between the adopted MSGT, the MCST and the CPT. Moreover, the impacts of the geometrical configuration as well as the elastic foundation parameters on the static bending and free vibration characteristics are illustrated in the numerical studies. This paper also explores the thickness of the active layer effect on the free vibration behaviour in combination with the power conversion efficiency (PCE) of the OSC.
