Down-Shifting in the YAM: Ce3+ + Yb3+ System for Solar Cells.

Bartosz Fetliński,Michał Malinowski,Sebastian Turczyński,Paweł Szczepański

doi:10.3390/ma14112753

Bartosz Fetliński, Michał Malinowski + Show 2 more

Open Access

https://doi.org/10.3390/ma14112753

Copy DOI

Abstract

In this work, we investigate Ce3+ to Yb3+ energy transfer in Y4Al2O9 (YAM) for potential application in solar spectrum down-converting layers for photovoltaic devices. Photoluminescence properties set, of 10 samples, of the YAM host activated with Ce3+ and Yb3+ with varying concentrations are presented, and the Ce3+ to Yb3+ energy transfer is proven. Measurement of highly non-exponential luminescence decays of Ce3+ 5d band allowed for the calculation of maximal theoretical quantum efficiency, of the expected down-conversion process, equal to 123%. Measurements of Yb3+ emission intensity, in the function of excitation power, confirmed the predominantly single-photon downshifting character of Ce3+ to Yb3+ energy transfer. Favorable location of the Ce3+ 5d bands in YAM makes this system a great candidate for down-converting, and down-shifting, luminescent layers for photovoltaics.

Highlights

The enhanced efficiency of photovoltaic devices, in the 300–500 nm spectral range, would improve the performance of devices operating under diffused solar irradiation
The external quantum efficiency (EQE) is defined as a ratio of a number of carriers participating in the photocurrent and number of photons reaching the surface of a photovoltaic device
Down-shifting, a single photon process, brings any benefit for a photovoltaic device only if EQE is larger in the emission spectral range than in the absorption band, as only a higher photocurrent may be obtained

Summary

Introduction

The enhanced efficiency of photovoltaic devices, in the 300–500 nm spectral range, would improve the performance of devices operating under diffused solar irradiation. This feature makes the idea of solar spectrum converters important for off-grid systems, as it would improve their performance under overcast and low irradiance conditions, improving their reliability and decreasing the probability of loss of load [1]. Down-shifting, a single photon process, brings any benefit for a photovoltaic device only if EQE is larger in the emission spectral range than in the absorption band, as only a higher photocurrent may be obtained. The main advantage of Ce3+ + Yb3+ system, in comparison with other rare-earth ions pairs such as

Methods

Results

Conclusion