Mechanical stability analysis of flexible perovskite solar cells via opto-electro-mechanical simulation

As emerging next-generation photovoltaics, the performance of flexible perovskite solar cells has been extensively studied. However, the in-depth understanding of mechanical stability and corresponding fatigue life of each layer still lags behind. In this work, an opto-electro-mechanical simulation is performed to investigate the effect of mechanical behaviors on both optoelectronic characteristics and device stability under bending deformation. The formation of fractures and energy accumulation of each layer in device, which affect their fatigue life, are analyzed systematically and quantitatively. For n-i-p configuration, Young's modulus of electron transport layer and perovskite, as well as the deposition position of the metal layer, play a decisive role in mechanical stability. Among them, perovskite layer with small Young's modulus is more conducive to prolonging device lifetime, while electron transport layer needs to make a trade-off between bearing greater stress on itself and causing greater energy accumulation to perovskite. Furthermore, the interface between electron transport layer and perovskite where cracks generate and penetrate deep into perovskite, is the main position limiting overall device fatigue life. The findings shed light on mechanical stability with respect to fatigue life, which draws significant conclusions for the design of stable flexible perovskite solar cells.