Nankai University’s Yongsheng Liu in Angewandte Chemie: 20.82%! A D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–......Nankai University’s Yongsheng Liu in Angewandte Chemie: 20.82%! A D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A–D–A......
Release Date:
2025-03-26 16:42
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Two-dimensional (2D) Ruddlesden–Popper (RP) perovskites have emerged as promising photovoltaic materials. However, the large dielectric mismatch and high exciton binding energy arising from the insulating spacer layers hinder further improvements in their photovoltaic efficiency.
Based on this, Liu Yongsheng and others from Nankai University Two semiconductor spacers, MeBThMA and CNBThMA, were developed for 2D RP perovskite solar cells. Compared with MeBThMA, the CNBThMA spacer, which features a donor–acceptor (D–A) architecture, exhibits a larger dipole moment and adopts a face-to-face molecular stacking arrangement in single crystals. This unique D–A structure effectively mitigates the dielectric mismatch between the organic and inorganic layers, facilitating favorable energy-level alignment, tuning anisotropic charge-transport properties, and enhancing the film quality of layered RP perovskites. Consequently, a device based on CNBThMA (with a nominal n = 5) achieved a champion efficiency of 20.82%, which, to the best of our knowledge, represents the record efficiency for a 2D RP PSC employing a semiconductor spacer layer. Our work has pioneered a novel approach to designing organic semiconductor spacers based on a donor–acceptor (D–A) architecture for high-efficiency 2D perovskite solar cells. This paper was recently published in the journal under the title “Semiconductor Spacers with Donor-Acceptor Structure Drive 2D Ruddlesden-Popper Perovskite Solar Cells Beyond 20% Efficiency.” Angewandte Chemie International Edition Above 。
Device Fabrication
Device Structure ：
ITO/NiOx/SAM/PVSK/PC61BM/BCP/Ag
1. Wash the ITO glass thoroughly, perform UV treatment for 20 minutes, deposit NiOx via spin coating at 3000 rpm for 30 seconds, and anneal at 100°C for 10 minutes; then spin coat a 0.3 mg/mL solution of 3-PACI(cF) at 5000 rpm, followed by annealing at 100°C for 10 minutes.
2. A 2D RP perovskite, (CNBThMA)2(MA0.8FA0.2)4Pb5I16, was prepared by mixing CNBThMAI, MAI, FAI, and PbI2 in a molar ratio of 2:3.2:0.8:5 (with a Pb2+ concentration of 0.91 M in the precursor solution composed of DMF:DMSO:MeCN = 5:5:1). MACl was then added to the precursor solution at a weight ratio of 0.4:1 relative to the combined mass of MAI and FAI. The resulting solution was stirred at 70°C for 3 hours and subsequently cooled to room temperature before use. Spin-coating was performed under the following conditions: 1000 rpm for 3 seconds, followed by 3000 rpm for 5 seconds, and then 3500 rpm for 60 seconds; finally, a reverse spin coating was carried out for 20 seconds using a CB:IPA mixture (1:1, containing 1 mg/mL MACl), followed by annealing in air at 105°C for 28 minutes.
3. Spin-coat PC61BM CB at 20 mg/mL for 30 s at 1500 rpm; spin-coat BCP IPA at 0.6 mg/mL for 60 s at 1000 rpm;
4. Evaporate 80 nm of Ag.
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