Halogen‐Bonded Hole‐Transport Material Suppresses Charge Recombination and Enhances Stability of Perovskite Solar Cells. Issue 35 (8th August 2021)

• Record Type: Journal Article
• Authors: Canil, Laura; Salunke, Jagadish; Wang, Qiong; Liu, Maning; Köbler, Hans; Flatken, Marion; Gregori, Luca; Meggiolaro, Daniele; Ricciarelli, Damiano; De Angelis, Filippo; Stolterfoht, Martin; Neher, Dieter; Priimagi, Arri; Vivo, Paola; Abate, Antonio
• Is Part Of: Advanced energy materials. Volume 11:Issue 35(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-08
• Subjects: halogen bonding -- hole‐transport materials -- interfaces -- perovskite solar cells; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202101553
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Interfaces play a crucial role in determining perovskite solar cells, (PSCs) performance and stability. It is therefore of great importance to constantly work toward improving their design. This study shows the advantages of using a hole‐transport material (HTM) that can anchor to the perovskite surface through halogen bonding (XB). A halo‐functional HTM (PFI) is compared to a reference HTM (PF), identical in optoelectronic properties and chemical structure but lacking the ability to form XB. The interaction between PFI and perovskite is supported by simulations and experiments. XB allows the HTM to create an ordered and homogenous layer on the perovskite surface, thus improving the perovskite/HTM interface and its energy level alignment. Thanks to the compact and ordered interface, PFI displays increased resistance to solvent exposure compared to its not‐interacting counterpart. Moreover, PFI devices show suppressed nonradiative recombination and reduced hysteresis, with a V oc enhancement of ≥20 mV and a remarkable stability, retaining more than 90% efficiency after 550 h of continuous maximum‐power‐point tracking. This work highlights the potential that XB can bring to the context of PSCs, paving the way for a new halo‐functional design strategy for charge‐transport layers, which tackles the challenges of charge transport and interface improvement simultaneously. Abstract : A novel hole‐transport material (HTM) with the ability to bind to perovskites via halogen bonding is synthesized. Thanks to this interaction, the HTM molecules form a homogenous and ordered layer, improving the perovskite/HTM interface. This results in enhanced open circuit voltage and stability, showing the advantages of using halo‐functional HTMs in perovskite solar cells.