Thiophene Terminated Fullerene Derivatives for Interfacial Modification toward High Efficiency MAPbI₃ Perovskite Solar Cells

Abstract

Interface engineering has become a critical process to fabricate efficient and stable planar heterojunction perovskite solar cells (PSCs), as the degradation of perovskite, hysteresis, and photo and thermal instability can all be triggered by the defective interfaces of PSCs. Herein, two fullerene derivatives, NMPPF and NMTTF, have been designed as interlayers between the MAPbI 3 and TiO 2 electron transport layer. The thiophene terminals of NMTTF have been found to effectively passivate the uncoordinated Pb 2+ of perovskite, reducing trap density and charge recombination of PSCs as well as facilitating charge transport at the perovskite and TiO 2 interface. Compared to the reference MAPbI 3 PSC with a maximum power conversion efficiency (PCE max ) of 18.7% and serious hysteresis (ΔPCE = 7.2%), PSCs incorporating NMTTF achieve a PCE max of 19.5% with minor hysteresis (ΔPCE = 1.2%) and outperform the performance of NMPPF (PCE max = 18.0%, ΔPCE = 2.3%) and PC 61 BM (PCE max = 18.9%, ΔPCE = 1.4%) modified PSCs. Unencapsulated PSCs adopting these NMPPF and NMTTF interlayers also exhibit good storage stability, maintaining 80% of their initial PCEs after storing in ambient for 30 days. This work demonstrates that the thiophene moiety can be an efficient defect passivation unit to design new fullerene molecules for interfacial engineering of PSCs with high efficiency and stability.

Thiophene Derivatives as Ligands for Highly Luminescent and Stable Manganese-Doped CsPbCl3 Nanocrystals

“…In the FT-IR spectra ( Supplementary Figure S3 ), a characteristic peak of thiophene appeared at 721 cm −1 ( Choi et al, 2021 ). The characteristic peaks of the thiophene are also shown in the 1 H-NMR spectra ( Supplementary Figure S4 ), in which δ of 7.34 and 7.12 ppm ( Zhou et al, 2015 ; Wang Hui et al, 2020 ) are the resonance peaks of hydrogen on the thiophene ring. These results confirm that TBA was indeed added on the surface of CPCM NCs.…”

Targeted Molecular Design of Functionalized Fullerenes for High‐Performance and Stable Perovskite Solar Cells

“…Subsequently, they explored another novel fulleropyrrolidine, NMTTF, with thiophene terminal moieties emanating from the fullerene cages, which was then incorporated between TiO 2 ETLs and perovskite layers. [ 47 ] The NMTTF‐based PSC achieved a maximum PCE of 19.5% with minor hysteresis in comparison to the reference PSC with a PCE of 18.7% and serious hysteresis, which contributed from the effective passivation of the uncoordinated Pb 2+ in perovskite by the thiophene terminals. By taking advantage of the strong interaction between sulfur and gold, Hong et al further studied gold nanoparticle's functionalized fullerene derivative (C 60 ‐BCT@Au NPs) as displayed in Figure 3g.…”

Consolidating a Pb–X framework via multifunctional passivation with fluorinated zwitterions for efficient and stable perovskite solar cells

“…[22][23][24][25][26][27][28] For instance, Lewis-base-like thiophene or pyridine can usually act as an electron donor to support Lewis acid-base reactions with under-coordinated lead ions. [29][30][31] Nevertheless, most of these passivators can only passivate one type of defect through ionic bonds or coordination bonds. To address this issue, the zwitterion bethanechol chloride (BTCC) has been introduced into perovskites, and this can simultaneously passivate both positive and negative ionic defects and stabilize the Pb-I framework.…”