Sequential Deposition Processing to Control Vertical Composition Distribution toward High‐Performance and Stable Inverted Organic Solar Cells

Abstract Sequential deposition (SD) is widely applied in the fabrication of high‐performance organic solar cells (OSCs). Nevertheless, the feasibility of SD in inverted photovoltaic devices is rarely mentioned. Moreover, the vertical component distribution in SD‐processed devices is still under debate. This study demonstrates that SD can achieve the entire bulk heterojunction morphology by precisely controlling the morphology of the active layer. To further promote photovoltaic performance, two post treatments, thermal annealing (TA) and solvent vapor annealing (SVA), are conducted to compare their effects on SD‐processed inverted photovoltaic devices. The results verify that SD can significantly enhance the thermal stability of devices. This work provides a valuable insight for systematically understanding SD processing and the preparation of stable inverted OSCs with superior performance.