Efficient Polymer Solar Cells Spray‐Coated from Non‐Halogenated Solvents towards Practical Fabrication

Abstract

AbstractIn the past decade, the power conversion efficiencies (PCEs) of polymer solar cells (PSCs) have been improved significantly. However, most efficient PSCs are based on halogenated solvents and the spin‐coating technique. To meet the requirements of practical fabrication, PSCs processed from non‐halogenated solvents using scalable deposition techniques are required. In this work, a non‐halogenated solvent system, o‐xylene/benzyl phenyl ether (BPE), was utilized to fabricate PSCs. The PSC obtained through spin coating from o‐xylene/BPE exhibited a high PCE comparable to a PCE spin‐coated from halogenated solvent. The nanostructures of the films processed from different solvents were investigated systematically to understand their performance evolution. Importantly, a spray‐coating technique compatible with the roll‐to‐roll process was employed to fabricate PSCs using an eco‐compatible ink formulation. The PSC spray coated from o‐xylene/BPE in ambient atmosphere gave rise to a PCE of 7.74 % comparable to that of devices spin‐coated from halogenated solvents, which demonstrated a significant potential for further practical fabrication.