Interfacial Buffering Breakthrough Pushes Organic Solar Cell Efficiency to Record 20.21 Percent Milestone

Researchers achieve record 20.21% efficiency in organic solar cells using a crystalline buffer layer to prevent solvent erosion during manufacturing.

By: AXL Media

Published: May 1, 2026, 8:44 AM EDT

Source: Information for this report was sourced from EurekAlert!

Overcoming Structural Hurdles in Organic Photovoltaics

As the global transition toward sustainable energy accelerates, organic solar cells have emerged as a frontrunner for next-generation power applications due to their lightweight and flexible properties. However, the production of high-efficiency pseudo-planar heterojunction structures has long been hindered by a phenomenon known as solvent-induced damage. During the layer-by-layer deposition process, the solvents used for the top layer often swell or erode the underlying material, leading to poor charge transport. According to a study published in the Chinese Journal of Polymer Science, researchers have found a way to bypass this degradation through a specialized interfacial engineering technique.

The Role of Crystalline Networks in Erosion Resistance

The core of this scientific advancement is the introduction of a highly crystalline polymer donor, known as D18, which serves as a protective buffer between the donor and acceptor layers. This buffer layer creates a dense, fibrillar network that acts as a physical barrier against solvent penetration during manufacturing. By establishing this erosion-immune interface, the researchers were able to preserve the structural integrity of the underlying layers. This mechanical protection ensures that the solar cell maintains a well-defined heterojunction, which is essential for transforming sunlight into electricity without significant energy loss.

Optimizing Vertical Phase Separation for Charge Transport

Beyond mere physical protection, the interfacial buffer layer plays a critical role in regulating the internal morphology of the solar cell. The presence of the crystalline network promotes a more distinct gradient distribution between the donor and acceptor components, a process known as vertical phase separation. This optimized internal structure creates more efficient pathways for charges to move through the device while simultaneously reducing interfacial defects. By enhancing molecular packing, the system suppresses non-radiative recombination losses, making the process of exciton dissociation far more effective than in conventional binary solar systems.