Stabilizing Perovskite-Substrate Interfaces for High-Performance Perovskite Modules

August 19, 2021

In this study, we found that dimethyl sulfoxide (DMSO), which is a liquid additive broadly applied to enhance perovskite film morphology, was trapped during film formation and led to voids at perovskite-substrate interfaces that accelerated the film degradation under illumination. These voids cause charge recombination at the voids surface and a reservoir of decomposition products, which accelerates material and device degradation under light.

Scientific Achievement

Our study revealed that perovskites crystalize from top to bottom during solvent evaporation. We further discovered that DMSO, which is a liquid additive broadly applied to enhance perovskite film crystallinity, was trapped during film formation and led to voids at perovskite-substrate interfaces that accelerated the film degradation under illumination. Partial replacement of DMSO with solid-state carbohydrazide reduces interfacial voids.

Significance and Impact

The interfaces of perovskite solar cells are important in determining their efficiency and stability, but the morphology and stability of imbedded perovskite-substrate interfaces have received less attention than top interfaces. This study boosted the efficiency of perovskite solar cells and stability and resulted in a new world record of module efficiency (19.3% and 19.2%, with aperture areas of 18.1 and 50.0 square centimeters).

Research Details

  • Discovered the presence of a large density of voids at the embedded perovskite-substrate interface by peeling off the perovskite films to examine that interface
  • Figured out the voids were caused by the entrapped DMSO during the top-to-down drying process
  • Discovered partial replacement of DMSO by solid-state carbohydrazide reduces interfacial voids

DOI: 10.1126/science.abi6323

Related People

Jinsong Huang
University of North Carolina, Chapel Hill

Top left: Schematic shows how the voids are formed at the perovskite-substrate interfaces. Top right: Image of a perovskite-substrate interface. Middle left: Schematic of peeling off perovskite films from ITO glass substrates with an epoxy encapsulant for SEM characterization. Middle right: Schematic shows how the voids are formed at the perovskite-substrate interfaces through thermal annealing. Bottom left: Image of the perovskite-substrate interfaces of the blade-coated perovskite films that were prepared from the precursor solutions with different amounts of DMSO and then peeled off from ITO glass substrates. Bottom right: Schematic shows how the voids are formed at the perovskite-substrate interfaces when DMSO escapes.