Cellulose Nanocrystals–Tin‐Oxide Hybrid Electron Transport Layers for Solar Energy Conversion. Issue 30 (11th September 2022)

• Record Type: Journal Article
• Authors: Niazi, Muhammad Rizwan; Zhao, Heng; Lamarche, Renaud Miclette; Munir, Rahim; Trudel, Simon; Hu, Jinguang; Welch, Gregory C.
• Is Part Of: Advanced materials interfaces. Volume 9:Issue 30(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-11
• Subjects: cellulose nanocrystals -- electron transport layers -- interlayers -- slot‐die coating -- tin‐oxides; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202201363
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Petro‐derived organic cathode interlayers (CILs) can modify the tin‐oxide (SnO2 ) electron transport layer (ETL) in organic photovoltaics (OPVs) to address the energy‐level alignment, charge extraction, and device shelf‐life instability challenges. However, the potential eco‐hazardousness of petro sources used to synthesize such CILs and the toxicity of processing solvents warrant the discovery of sustainable and commercially viable substitutes. Herein, a low‐cost, biocompatible, and water‐processable CIL based on amine‐functionalized cellulose nanocrystals (CNC‐a) is introduced to enhance the performance of OPVs by mitigating surface defects of the SnO2 ETL. X‐ray photoelectron spectroscopy (XPS) reveals a reduction in water traps after SnO2 modification with CNC‐a. The electrical characterization shows that CNC‐a modification improves the conductivity of the SnO2 . CNC‐a inhibits charge recombination and improves the charge collection ability leading to power conversion efficiencies (PCEs) of >13% in halogen‐free solvent and air‐processed PBDB‐T‐SF (PM6):BTP‐4F‐12 (Y6‐C12)‐based OPVs. The SnO2 /CNC‐a bilayer ETL‐based devices exhibit relatively high shelf‐life device stability. Fully slot‐die‐coated (where SnO2, CNC‐a, and bulk heterojunction [PM6:Y6‐C12] are coated) large area bottom cathode cells (PCE > 10%) are demonstrated, showcasing the utility for scale‐up. This work opens a viable and sustainable pathway to develop bio‐derived materials for scalable OPVs. Abstract : A low‐cost, biocompatible, sustainable, and water‐processable cathode‐interlayer based on amine‐functionalized cellulose nanocrystals (CNC‐a) is presented. Scalable film printing of CNC‐a is showcased via slot‐die coating. CNC‐a passivates surface defects of the tin‐oxide electron transport layer, improves its electrical conductivity, and results in improved organic photovoltaic devices.