3D Electron Diffraction -- The Missing Slice for a Complete Nanoscale Analysis of Organic Solar Cells in TEM

TL;DR

This paper introduces 3D Electron Diffraction as a novel technique that enables comprehensive nanoscale structural analysis of organic solar cells within a TEM, overcoming limitations of traditional methods and enhancing understanding of their nanostructures.

Contribution

The paper presents elastically filtered 3D Electron Diffraction as a new method that provides full reciprocal- and real-space analysis in a single TEM, with high sensitivity to beam-sensitive organic materials.

Findings

Reproduces key structural parameters from GIWAXS

Provides true in-plane access and registration with imaging

Demonstrates generality across different OSC blends

Abstract

Optimizing the performance of organic solar cells (OSCs) hinges on a comprehensive understanding of their nanostructures, yet traditional characterization methods often fall short, delivering incomplete structural snapshots. We introduce elastically filtered 3D Electron Diffraction (3D ED) as a ground-breaking technique bridging full reciprocal- and real-space structural analysis within a single transmission electron microscope (TEM). Using solvent-vapor annealed DRCN5T:PC71BM, 3D ED reproduces key structural parameters from GIWAXS including lattice spacings, coherence lengths, and mosaicity, while uniquely delivering true in-plane access and direct registration with high-resolution imaging, diffraction imaging and nano-spectroscopy on the same sample. A low-dose, distributed tilt strategy plus energy filtering yields high signal-to-background below damage thresholds. Extension to a second archetypal blend (P3HT:PC71BM; annealing evolution) demonstrates generality. Our findings underscore the transformative potential of 3D ED, particularly in analysing beam-sensitive organic thin films. This paves the way for new avenues in advanced correlative structural characterization of OSCs and holds potential for application to a multitude of other nanostructured materials.