Enhanced Electron Extraction Capability of Polymer Solar Cells via Employing Electrostatically Self-Assembled Molecule on Cathode Interfacial Layer

ACS Appl Mater Interfaces. 2016 Mar;8(12):8224-31. doi: 10.1021/acsami.5b12394. Epub 2016 Mar 17.

Abstract

In this paper, high-performance inverted polymer solar cells (PSCs) with a modified cathode buffer layer, titanium dioxide:polyethylenimine (TiO2:PEI), are demonstrated. The TiO2-O-PEI transport layer was fabricated by electrostatically self-assembled monolayers (ESAM) of PEI molecules. Protonated amine functional groups of PEI can combine protons (H(+)) hydrolyzing from its aqueous solution. Also, PEI could produce ESAM on the surface of hydroxylated TiO2 because of its cationic characteristics. The incorporation of the TiO2-O-PEI layer enhances the photocurrent and power conversion efficiency (PCE) due to the improved interfacial electron transport and extraction of the TiO2-O-PEI surface and the increased light absorption of the active layer. The enhanced PCE, low-cost materials, and solution process of TiO2-O-PEI buffer layers provide a promising method for highly efficient PSCs.

Keywords: PEI; electron transport and extraction; electrostatically self-assembled monolayers; polymer solar cells; power conversion efficiency.

Publication types

  • Research Support, Non-U.S. Gov't