Enhancing Photovoltaic Performance Using Broadband Luminescent Down-Shifting by Combining Multiple Species of Eu-Doped Silicate Phosphors.

Wen-Jeng Ho,Chun-Hung Ho,Yu-Tang Shen,Bang-Jin You,Jheng-Jie Liu

doi:10.3390/nano7100340

Wen-Jeng Ho, Chun-Hung Ho + Show 3 more

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https://doi.org/10.3390/nano7100340

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Abstract

This paper demonstrates the application of a broadband luminescent downshifting (LDS) layer with multiple species of europium (Eu)-doped silicate phosphors using spin-on film technique to enhance the photovoltaic efficiency of crystalline silicon solar cells. The surface morphology of the deposited layer was examined using a scanning electron microscope (SEM). The chemical composition of the Eu-doped silicate phosphors was analyzed using energy-dispersive X-ray spectroscopy (EDS). The fluorescence emission of the Eu-doped silicate phosphors was characterized using photoluminescence (PL) measurements at room temperature. We also compared the optical reflectance and external quantum efficiency (EQE) response of cells with combinations of various Eu-doped phosphors species. The cell coated with two species of Eu-doped phosphors achieved a conversion efficiency enhancement (∆η) of 19.39%, far exceeding the ∆η = 15.08% of the cell with one species of Eu-doped phosphors and the ∆η = 8.51% of the reference cell with the same silicate layer without Eu-doped phosphors.

Highlights

The conversion efficiency of single band-gap solar cells is constrained by the need to match the band-gap of the cell material to the radiation spectrum of the sun
We investigated crystalline silicon solar cells coated with a layer comprising one or two species of 3 wt % europium-doped (Eu-doped) silicate phosphors
This study sought to improve the efficiency of crystalline silicon solar cells by coating them with a layer of SiO2 mixed with one species or two species of 3 wt % Eu-doped silicate phosphors

Summary

Introduction

The conversion efficiency of single band-gap solar cells is constrained by the need to match the band-gap of the cell material to the radiation spectrum of the sun. LDS is a passive method involving the application of a luminescent species above the solar cell to absorb light of short wavelengths and re-emit it at longer wavelengths. This requires materials with a high photoluminescent quantum yield (PLQY) and large Stokes shift LDS to improve the efficiency of crystalline silicon solar cells [16,17]. The high luminescence quantum efficiency and large Stokes-shift europium-ion (Eu+3) complexes make them excellent LDS species for crystalline silicon solar cells [18,19,20,21,22,23,24,25]. We used photovoltaic current density-voltage (J–V) measurements to compare the photovoltaic performance of crystalline solar cells with two species of Eu-doped phosphors, one species of phosphors, or a no phosphors layer

Preparation and Characterization of Eu-Doped Silicate Phosphors Layer

Findings

Conclusions