Self-Healing Optical Structures for Light-Trapping in Perovskite Solar Cells

Self-healing transparent polymers are advantageous for various optoelectronic devices to improve resilience and durability. However, most of these materials have been applied only as flat films and do not address the need for optical structures that can manipulate light. Here optical microstructures embossed on a self-healing polyurea film are presented which can autonomously recover from damage in ambient conditions. The polyurea film have a high optical transmittance above 90% and haze below 1.3%, and Young's modulus of 3.4 MPa. When applied as a protective light-trapping layer for perovskite solar cells, the champion device shows improved short circuit current density from 23.7 to 25.0 mA·cm⁻², and power conversion efficiency from 21.5% to 23.0%. Furthermore, the solar cell with the light-trapping layer has improved impact resistance and can recover its performance after being scratched. It is envisioned that self-healing optical structures can be realized for different geometries and materials in a range of optoelectronic applications to produce resilient and durable devices.