Search

Perovskite solar cells (PSCs) have demonstrated a high power conversion efficiency, however, the large energy loss due to non‐radiative recombination is the main challenge for further performance enhancement. Here, a surface treatment strategy is developed by heat‐induced decomposition of a thin interlayer 2,7‐Naphthaleneditriflate (NAP) to in situ reconstruct perovskite energetics. It is verified that the reconstructed perovskite surface energetics match better with the upper hole transport layer compared to the intrinsic condition. Spontaneous generation of n/n− homojunctions between the perovskite film bulk and the surface region promotes hole extraction, enhancing built‐in electric field, and thus significantly suppresses charge recombination at such perovskite hole‐selective heterojunctions. Moreover, the surface decomposed fluorine‐rich complexes passivate the defects and improve the crystallinity of the perovskite film. These advantages are confirmed by a remarkably improved efficiency from 20.52% for the control device to 23.37% for the treated one with excellent stability. The work provides a promising approach of in situ reconstructing perovskite surface and interface for the design of highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

Suppressing nonradiative recombination in perovskite solar cells (PSCs) is crucial for increases in their power conversion efficiency and operational stability. Here, it is reported that the synchronous use of a molecule daminozide (DA), as an interlayer and additive to judiciously construct a PTAA:F4TCNQ/DA/perovskite:DA hole‐selective heterojunction that diminishes thermionic losses for collecting holes at the buried interface between perovskites and PTAA:F4TCNQ, and reduces defect sites at such buried interfaces as well as in the perovskite film. The proposed "three birds with one stone" strategy significantly promotes charge transport, and both the interface carrier recombination and defect‐assisted recombination are suppressed. As a result, a remarkably improved efficiency of 22.15% and an impressive fill factor of 83.92% are achieved with excellent device stability compared to 19.04% of the control device. The two values are the highest records for polycrystalline MAPbI3‐based p‐i‐n structural PSCs reported to date. The work provides a promising approach of three birds with one stone, employing a functional material for further improvement of PSC performance. [ABSTRACT FROM AUTHOR]