Organic-inorganic lead halide perovskite solar cells (PSCs) exhibit the fast development with efficiency growing from 3.8% in 2009 to 24.2% in 2019. Current PSCs intended for commercialization in the near future require both high efficiency and good long-term stability. Most highly efficient PSCs utilize an n-type layer of mesoporous titanium dioxide or tin oxide in an n-i-p device configuration, in which organic conductors are widely used to transport holes into an adjoined metal. Thus far, a variety of efforts have been devoted to achieve a defect-less perovskite film with high-quality morphologies to realize reduced loss-in-potential outcomes and enhanced efficiency levels. In this talk, we will discuss several challenges that need to be addressed in improving the photovoltaic performance and the stability of the perovskite solar cells, i.e. (1) preparation of high crystalline film of (FAPbI₃)_1-x(MAPbBr₃)_x with a large grain size and a preferred orientation, (2) development of selective charge-transporting layers (CTL) with a superior stability, (3) interfacial control and energy level matching between the perovskite and the CTLs. We also continue to present our approach for realizing a long-term operating stability of PSCs with respect to the ion migration and the solid encapsulation. Our strategy as presented in this work will offer new directions for those involved in the fabrication of highly efficient and stable PSCs