Electrostatically Enhanced Buried Interface Binding of Self‐Assembled Monolayers for Efficient And Stable Inverted Perovskite Solar Cells

Journal Article · Mon Aug 11 00:00:00 EDT 2025 · Advanced Materials

DOI:https://doi.org/10.1002/adma.202508740· OSTI ID:3028832

Huang, Chuying ^[1]; Yang, Yi ^[1]; Liu, Cheng ^[1]; Chen, Hao ^[1]; Chaudhuri, Subhajyoti ^[1]; Jeon, Woo Cheol ^[1]; Li, Muzhi ^[2]; Rolston, Nicholas ^[2]; Bati, Abdulaziz S. R. ^[1]; Gilley, Isaiah W. ^[1]; Kumral, Boran ^[3]; Serles, Peter ^[3]; Filleter, Tobin ^[3]; Schatz, George C. ^[1]; Kanatzidis, Mercouri G. ^[1]; Chen, Bin ^[1]; Chen, Lin X. ^[1]; Sargent, Edward H. ^[4]

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1. Department of Chemistry Northwestern University 2145 Sheridan Rd Evanston IL 60208 USA
2. Ira A. Fulton Schools of Engineering Arizona State University Tempe AZ 85281 USA
3. Department of Mechanical and Industrial Engineering University of Toronto Toronto ON M5S 3G8 Canada
4. Department of Chemistry Northwestern University 2145 Sheridan Rd Evanston IL 60208 USA; Department of Electrical and Computer Engineering University of Toronto 35 St George Street Toronto ON M5S 1A4 Canada; Department of Electrical and Computer Engineering Northwestern University 2145 Sheridan Rd Evanston IL 60208 USA

Abstract Inverted p‐i‐n structure perovskite solar cells (PSCs) have outperformed traditional n‐i‐p PSCs in recent years. A key advancement is the use of self‐assembled monolayers (SAMs) as hole transport layers. One class of widely used SAMs is carbazole‐based phosphonic acids. However, it is found that these SAMs lack strong binding with transparent conducting oxides (TCO) and perovskite. The weak binding strength results in suboptimal interfacial adhesion of the buried interface, which limits the device's stability. Here, interfacial binding is enhanced by increasing the dipole moment that creates a strong interfacial electric field that enhances electrostatic interactions at the TCO/perovskite interface, while incorporating tailored functional groups in SAMs to improve chemical anchoring to TCO and binding to perovskite. Specifically, the donor‐acceptor SAM molecule 4‐(7‐(4‐(bis(4‐methoxyphenyl)amino)‐2,5‐difluorophenyl)benzo[c][1,2,5]thiadiazol‐4‐yl)benzoic acid (PAFTB) is employed, which features an enhanced dipole moment along with electron‐donating and electron‐withdrawing functional groups to optimize interfacial interactions. Compared to extensively used [2‐(9H‐carbazol‐9‐yl)ethyl]phosphonic acid (2PACz), PAFTB enhances total interfacial adhesion by 2.8 times, thereby improving the thermal stability of the layer. Using this approach, PSCs are demonstrated with a certified quasi‐steady‐state power conversion efficiency of 24.9% and maintain 80% of the initial efficiency after 900 h of maximum power point tracking at 85 °C.

• Research Organization: Energy Frontier Research Centers, Washington, DC (United States) (EFRC)
• Sponsoring Organization: Basic Energy Sciences; King Abdullah University of Science and Technology; National Science Foundation; Office of Science; Solar Energy Technologies Office; U.S. Department of Energy
• Grant/Contract Number: AC02-06CH11357; EE0010502
• Other Award/Contract Number: CHE 1955806; 2339233
• OSTI ID: 3028832
• Journal Information: Advanced Materials, Journal Name: Advanced Materials Journal Issue: 43 Vol. 37; ISSN 1521-4095; ISSN 0935-9648
• Publisher: Wiley
• Country of Publication: United States
• Language: English

Related Subjects

Interfacial adhesion
perovskite solar cells
self-assembled monolayer
stability