# An Experimentally Benchmarked Optical Study on Absorption Enhancement in Nanostructured a-Si/PbS Quantum Dot Tandem Solar Cells

## TL;DR

This paper presents a new nanostructure design to improve light absorption in a-Si/PbS quantum dot tandem solar cells for better efficiency.

## Contribution

A novel experimentally guided nanostructure design is introduced to enhance optical path length and reduce reflectance in tandem solar cells.

## Key findings

- Nanostructures increase optical path length by diffracting light to off-normal directions.
- Graded-index material stacks effectively suppress surface reflectance.
- The design offers a clear pathway for improving commercial tandem solar cell performance.

## Abstract

Tandem solar cells offer a promising route to surpass single-junction efficiency limits. The amorphous silicon (a-Si)/lead sulfide quantum dot (PbS QD) configuration is a strong candidate for broadband solar spectrum utilization. Planar devices with this material combination suffer from significant optical losses, making advanced light management essential. To address this, we propose a novel experimentally guided nanostructure design. Our proposed method utilizes nanostructures to increase the optical path length by diffracting light to off-normal directions and employs graded-index material stacks to suppress surface reflectance. This work establishes a clear design pathway and provides valuable insights into alternative light management strategies for the future commercialization of these tandem solar cells.