Abstract
2D Ruddlesden–Popper (RP) perovskite solar cells have manifested superior operation durability yet inferior charge transport compared to their 3D counterparts. Integrating 3D phases with 2D RP perovskites presents a compromise to maintain respective advantages of both components. Here, the spontaneous generation of 3D phases embedded in 2D perovskite matrix is demonstrated at room temperature via introducing S‐bearing thiophene−2−ethylamine (TEA) as both spacer and stabilizer of inorganic lattices. The resulting 2D/3D bulk heterojunction structures are believed to arise from the compression‐induced epitaxial growth of the 3D phase at the grain boundaries of the 2D phase through the Pb−S interaction. The as‐prepared 2D TEA perovskites exhibit longer exciton diffusion length and extended charge carrier lifetime than the paradigm 2D phenylethylamine (PEA)‐based analogues and hence demonstrate an outstanding power conversion efficiency of 7.20% with significantly increased photocurrent. Dual treatments by NH4Cl and dimethyl sulfoxide are further applied to ameliorate the crystallinity and crystal orientation of 2D perovskites. Consequently, TEA‐based devices exhibit a stabilized efficiency over 11% with negligible hysteresis and display excellent ambient stability without encapsulation by preserving 80% efficiency after 270 h storage in air with 60 ± 5% relative humidity at 25 °C.
Highlights
Users may download and print one copy of any publication from the public portal for the purpose of private study or research
Since S atom is believed to bond with Pb atom, we suggest that S-bearing thiophene rings will interact with Pb−I octahedrons, form strong dipoles with Pb atoms, and result in large distortions in 2D lattices, which directly modulates the crystallization dynamics and induces the formation of 3D phases
Note that the small peaks around 137 and 142 eV are often observed in Pb 4f spectra, which is most likely attributed to the signal of Pb0 owning to the X-ray beam damage during the measurement.[37,38]. These X-ray photoelectron spectroscopy (XPS) results provide solid evidence for the interaction between thiophene ring and Pb−I octahedrons, which lead to the following merits. It improves the electronic coupling between the perovskite octahedrons and the spacing cations at the interface, which provides additional driving force for both exciton dissociation and interphase charge transfer as discussed above, and enhances the stability of the inorganic perovskite lattices compared to PEA-based perovskites, which is demonstrated from the stability test of thin films at room temperature with a high relative humidity (RH) of 70 ± 5 % as shown in Figure S4 in the Supporting Information
Summary
Where Qe is the relative decrease percent of PL intensity caused by quench layer, PLi and PLQ are the integrated PL intensity before and after quench treatment, LD is the diffusion length, d is the thickness of the perovskite films. Note that the small peaks around 137 and 142 eV are often observed in Pb 4f spectra, which is most likely attributed to the signal of Pb0 owning to the X-ray beam damage during the measurement.[37,38] These XPS results provide solid evidence for the interaction between thiophene ring and Pb−I octahedrons, which lead to the following merits It improves the electronic coupling between the perovskite octahedrons and the spacing cations at the interface, which provides additional driving force for both exciton dissociation and interphase charge transfer as discussed above, and enhances the stability of the inorganic perovskite lattices compared to PEA-based perovskites, which is demonstrated from the stability test of thin films at room temperature with a high RH of 70 ± 5 % as shown in Figure S4 in the Supporting Information. These two competitive processes achieve an optimal balance in co-treated device and result in the best
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
