Study on Thin Film Encapsulation Coating for Long-term Stable Organic Solar Cells

In this study, thin film encapsulation (TFE) of aluminum oxide (Al2O3) and zirconium dioxide (ZrO2) deposited by atomic layer deposition (ALD) was applied on an organic solar cell device composed of PBDB-T:ITIC. To evaluate the long-term stability of the device, the maximum power point tracking (MPPT) test was conducted under illumination. As a result, the encapsulated device showed 100% stable performance for 120 hours compared to the device without TFE. Although the solar cell device performance decreased slightly after ALD process treatment due to thermal damage of hole transport layer (HTL), it showed very good characteristics in terms of long-term stability. In addition to the stability improvement effect, the TFE film also shows the effect of improving the transmittance of light incident on the solar cell, such as anti-reflection coating (ARC). This shows the possibility that TFE coating technology can contribute to both sta-bility and performance improvement of solar cells in the future.