Nanostructured Back Electrode for Thin Perovskite Quantum Dot Solar Cells

The patent introduces a nanostructured back electrode with three-dimensional nanopyramid patterns instead of a flat two-dimensional surface. This dimensional change creates multiple light scattering interfaces and extends the optical path length within the photoactive layer, enabling enhanced light absorption without increasing the physical thickness of the layer. The nanopyramid structures with heights of 50-200 nm provide vertical dimensionality that traps light through repeated scattering events.

The patent employs curved nanopyramid structures with rounded apexes rather than sharp edges. These curved surfaces enhance light scattering through multiple reflections and reduce parasitic absorption at sharp corners. The spherical or conical geometry of the nanopyramids optimizes light trapping by directing scattered light back into the photoactive layer, improving absorption efficiency without requiring increased thickness.

By transforming the back electrode from a flat plane to a three-dimensional nanopyramid array, the patent effectively increases the optical interaction volume without increasing the physical thickness of the photoactive layer. The vertical nanopyramid structures create additional light scattering events that extend the optical path length, compensating for the limited physical thickness and maintaining high light absorption capacity.

The nanostructured back electrode creates a porous-like architecture with numerous nanopyramid structures that provide multiple scattering interfaces. This porous morphology increases the effective surface area and light-matter interaction volume, enabling enhanced light absorption in a compact thin-film structure while maintaining short charge carrier diffusion paths.

The patent optimizes specific parameters of the nanopyramid structure including height (50-200 nm), base diameter, and spacing to achieve maximum light scattering efficiency. By carefully controlling these geometric parameters, the structure provides enhanced light absorption while maintaining manufacturability through established nanofabrication techniques, balancing performance improvement with device complexity.

The back electrode is segmented into an array of discrete nanopyramid structures rather than a continuous flat surface. This segmentation creates multiple independent scattering centers that collectively enhance light absorption. The segmented structure can be fabricated using standard lithography and etching processes, making the complexity manageable through conventional manufacturing approaches.