Stable and Highly Flexible Perovskite Solar Cells with Power Conversion Efficiency Approaching 20% by Elastic Grain Boundary Encapsulation

Here,we show that flexible perovskite solar cells(PSCs)with high operational stability and power conversion efficiency(PCE)approaching 20%were achieved by elastic grain boundary(GB)encapsulation.An introduction of trimethyltrivinylcyclotrisiloxane(V3D3)and solvent annealing(SA)resulted in an in situ cross-linking reaction between GBs and enlarged grain size that enabled oriented charge-transport properties to be achieved synchronously,leading to reduced sheet resistance with a high fill factor(FF)up to 82.93%in flexible PSCs.