Efficient Organic Solar Cells with Polymer-Small Molecule: Fullerene Ternary Active Layers

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) are a promising renewable energy technology.
• Ternary active layers offer potential for improved performance in OSCs.
• Understanding morphology and charge transport is crucial for efficient OSCs.

Purpose of the Study:

• To fabricate and characterize organic solar cells (OSCs) with a polymer-small molecule-fullerene ternary active layer.
• To investigate the factors contributing to enhanced power conversion efficiency (PCE) in these ternary OSCs.
• To provide a facile fabrication route for efficient OSCs.

Main Methods:

• Fabrication of OSCs with a ternary active layer.
• Analysis of power conversion efficiency (PCE), short-circuit current density (Jsc), and fill factor (FF).
• Spectroscopic analysis (absorption, external quantum efficiency).
• Morphological characterization using grazing-incidence wide-angle X-ray scattering (GIWAXS), transmission electron microscopy (TEM), and atomic force microscopy (AFM).

Main Results:

• The ternary active layer significantly enhanced PCE, Jsc, and FF.
• Improved light absorption by the small molecule contributed to higher photocurrent.
• Reduced π-π stacking distance, good miscibility, and a rougher film surface facilitated charge transport.
• Increased hole mobility of the polymer donor and electron mobility of the fullerene acceptor were observed.

Conclusions:

• The polymer-small molecule-fullerene ternary active layer is an effective strategy for enhancing OSC performance.
• Optimized morphology and charge transport are key to achieving high PCE in ternary OSCs.
• This study presents a straightforward approach for developing efficient organic solar cells.