Metal-oxide-based charge-transport layers have played a pivotal role in the progress of perovskite solar cells. Yet metal-oxide/perovskite interfaces are often highly defective, owing to both metal-oxide and perovskite surface defects. This results in non-radiative recombination and impedes charge transfer. Moreover, during operation, such interfaces may suffer from undesirable chemical reactions and mechanical delamination issues. Solving this multifaceted challenge requires a holistic approach to concurrently address the interfacial defect, charge-transfer, chemical stability and delamination issues, to bring perovskite solar cell technology closer to commercialization. With this motivation, we review and discuss the issues associated with the metal-oxide/perovskite interface in detail. With this knowledge at hand, we then suggest solutions based on molecular engineering for many, if not all, challenges that encumber the metal-oxide/ perovskite interface. Specifically, in light of the semiconducting and ultrafast charge-transfer properties of dyes and the recent success of self-assembled monolayers as charge-selective contacts, we discuss how such molecules can potentially be a promising solution for all metal-oxide/perovskite interface issues.Sections the mesoporous TiO 2 layer enabled chemisorption of a large quantity of dye molecules, the device could harvest a high proportion of the incident solar energy flux, and delivered a PCE of 7.1-7.9%. Nonetheless, the liquid electrolyte had many limitations, such as a limited Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author selfarchiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

No abstract