# Dual Spectral Matching in Perovskite Solar Cells via Upconverting plus Downshifting Nanoparticles

## TL;DR

This paper explores using lanthanide-doped nanoparticles to improve perovskite solar cell efficiency by converting unusable light into usable wavelengths.

## Contribution

The novel use of dual spectral matching via upconverting and downshifting nanoparticles in perovskite solar cells is introduced.

## Key findings

- ERN nanoparticles increased power conversion efficiency by 22.19%.
- TMN nanoparticles improved efficiency by 13.23%.
- Downshifting emission and surface passivation reduced recombination losses.

## Abstract

Maximizing solar cell efficiency is a critical step toward
revolutionizing
photovoltaic technologies and harnessing the full potential of light
for energy conversion. This study investigates the incorporation of
NaGdF4:Yb3+,Tm3+@NaGdF4:Eu3+ (TMN) and NaGdF4:Yb3+,Er3+@NaGdF4:Eu3+ (ERN) nanoparticles into
perovskite solar cells (PSCs) to improve their power conversion efficiency.
The nanoparticles were synthesized through thermolysis and characterized
using multiple techniques, including photoluminescence spectroscopy,
quantum yield measurements, transmission electron microscopy, X-ray
diffraction, solar simulation, and external quantum efficiency assessments.
These lanthanide-doped NPs exhibited strong downshifting and minor
upconversion luminescence, acting like optical translators that reshape
poorly absorbed light into usable wavelengths. Devices incorporating
the ERN nanoparticles demonstrated a 22.19% relative increase in power
conversion efficiency, while those with TMN showed a 13.23% improvement.
These enhancements are attributed mainly to the effective downshifting
emission of Eu3+ and improved surface passivation from
the core–shell architecture, which together reduce recombination
losses and improve charge carrier dynamics. These findings underscore
the potential of photon-converting lanthanide-based materials to address
spectral absorption limitations in PSCs, offering a promising route
toward next-generation photovoltaic technologies.