Benefiting from Spontaneously Generated 2D/3D Bulk‐Heterojunctions in Ruddlesden−Popper Perovskite by Incorporation of S‐Bearing Spacer Cation

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 NH 4 Cl 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.

Engineering fluorinated-cation containing inverted perovskite solar cells with an efficiency of >21% and improved stability towards humidity

“…It appears at first sight that the absorption spectra of films containing up to 10 mol% (FEA) 2 PbI 4 were essentially identical to that of the MAPbI 3 with an absorption onset of around 760 nm 28 , with only the 50 mol% (FEA) 2 PbI 4 -containing film being significantly different. The 50 mol% (FEA) 2 PbI 4 containing film had distinctive absorbance peaks at around 403, 499, 547, and 569 nm, which were in line with previous reports on 2D/3D perovskite-containing films 29 , 30 and could be ascribed to the excitonic absorption of 2D-perovskite phases with n = 1–4 layers, respectively. Supplementary Fig.…”

Water‐Assisted Crystal Growth in Quasi‐2D Perovskites with Enhanced Charge Transport and Photovoltaic Performance

“…The difference in the evolution of TA signals assigned to the different bands reveals the scenario of charge transfers which tend to from higher energy phases (corresponding to smaller n ‐values) to low energy 3D phase ( n ≈ ∞), leading to the populating charges at the 3D components and increased TA signals. [ 13,35,40 ] Through fitting the rising part of the TA dynamics probed at n ≈ ∞ phase, we identified a shorter carrier populating time (25.1 ps) in the water‐processed film, compared to a population time of 44.3 ps in the control film. The results point to that charge transfers (most likely the electrons in our case) from the smaller‐ n phases to n ≈ ∞ phase may occur more efficiently in the perovskite film processed with the water‐containing precursors, which is a key attribute to the enhancements of J sc and PCE in the solar cells.…”

Self‐Additive Low‐Dimensional Ruddlesden–Popper Perovskite by the Incorporation of Glycine Hydrochloride for High‐Performance and Stable Solar Cells

“…[ 31 ] Whereas, most of the researchers focused on the design on the new type of low dimensional RP perovskite materials. [ 32–36 ] Yan et al prepared the 2D/3D bulk‐heterojunctions RP perovskite devices via introducing the S‐bearing thiophene‐2‐ethylamine spacer cation, exhibiting a stabilized PCE over 11% with negligible hysteresis. [ 32 ] Zhang and co‐workers enhanced the charge transport in 2D perovskites via 4‐fluorophenethylene lammonium (F‐PEA) and obtained a PCE over 13% for (F‐PEA) 2 MA 4 Pb 5 I 16 ‐based PSCs with high thermal stability.…”

“…[ 32–36 ] Yan et al prepared the 2D/3D bulk‐heterojunctions RP perovskite devices via introducing the S‐bearing thiophene‐2‐ethylamine spacer cation, exhibiting a stabilized PCE over 11% with negligible hysteresis. [ 32 ] Zhang and co‐workers enhanced the charge transport in 2D perovskites via 4‐fluorophenethylene lammonium (F‐PEA) and obtained a PCE over 13% for (F‐PEA) 2 MA 4 Pb 5 I 16 ‐based PSCs with high thermal stability. [ 33 ] Chen's team successfully employed phenyltrimethylammonium (PTA + ) as the organic interlayer spacer to prepare the 2D RP perovskite devices that show superior optoelectronic properties with the PCE up to 11.53%.…”