Optimizing the morphology of all-polymer solar cells for enhanced photovoltaic performance and thermal stability

Due to the complicated film formation kinetics,morphology control remains a major challenge for the development of efficient and stable all-polymer solar cells(all-PSCs).To overcome this obstacle,the sequential deposition method is used to fabricate the photoactive layers of all-PSCs comprising a polymer donor PTzBI-oF and a polymer acceptor PS1.The film morpho-logy can be manipulated by incorporating amounts of a dibenzyl ether additive into the PS1 layer.Detailed morphology investig-ations by grazing incidence wide-angle X-ray scattering and a transmission electron microscope reveal that the combination merits of sequential deposition and DBE additive can render favorable crystalline properties as well as phase separation for PTzBI-oF:PS1 blends.Consequently,the optimized all-PSCs delivered an enhanced power conversion efficiency(PCE)of 15.21%along with improved carrier extraction and suppressed charge recombination.More importantly,the optimized all-PSCs re-main over 90%of their initial PCEs under continuous thermal stress at 65 ℃ for over 500 h.This work validates that control over microstructure morphology via a sequential deposition process is a promising strategy for fabricating highly efficient and stable all-PSCs.