GHK-Cu Peptide Boosts Efficiency of Polymer Solar Cells

Polymer solar cells (PSCs) are a promising technology for renewable energy due to their flexibility, transparency, and low manufacturing cost. However, their power conversion efficiency (PCE) often lags behind traditional silicon-based solar cells, limiting widespread adoption. Enhancing the active layer's morphology and charge transport properties is crucial for improving PSC performance, and this study investigates how the peptide GHK-Cu can be incorporated into ternary polymer solar cells to optimize their active layer structure and boost efficiency.

The incorporation of GHK-Cu significantly improved the performance of the ternary polymer solar cells. The optimal concentration of 0.1 wt % GHK-Cu led to a peak power conversion efficiency (PCE) of 17.20%. This represents a substantial increase compared to the binary control device (without GHK-Cu), which achieved a PCE of 16.03%, demonstrating a relative improvement of approximately 7.3%. The most significant finding was that 0.1 wt % GHK-Cu enhanced the short-circuit current density (Jsc) and fill factor (FF) by optimizing the active layer's crystallinity and phase separation, leading to more efficient charge transport and reduced recombination. Specifically, the Jsc (a measure of current generated under light) increased from 25.21 mA cm⁻² in the binary device to 26.19 mA cm⁻² with GHK-Cu, and the FF (a measure of how well the solar cell converts the generated current into useful power) improved from 75.10% to 77.50%. These improvements were attributed to GHK-Cu acting as a morphology regulator, creating a more favorable nanoscale structure for charge generation and collection.