Enhancing the performance of multi-crystalline silicon photovoltaic module by encapsulating high efficient Eu3+ complex into its pre-existing EVA layer

Luminescent down shifting (LDS) technique is one effective way to improve the poor response of multi-crystalline silicon (mc-Si) photovoltaic (PV) modules at short wavelength less than 400 nm. Eu3+ complexes are effective LDS species for PV modules due to their large stokes’ shift and high luminescent quantum efficiency (LQE). Although Eu3+ complexes have been utilized in PV modules as LDS species widely, they have not been encapsulated into the pre-existing poly-ethylene vinyl acetate (EVA) layer of modules between glass and solar cell by now. The aim of our work is to enhance the performance of mc-Si PV modules by encapsulating high efficient Eu3+ complexes into their pre-existing EVA layers which would not modify the well-established manufacturing process for PV modules. In this work, two Eu3+ complexes with different absorption spectrum were encapsulated into the commercial EVA layer by soaking method for the first time and used in the encapsulation of mc-Si PV modules. Hereinto, Eu(TTA)3(TPPO)2 (TTA = 2-thenoyltrifluoroacetonate, TPPO = triphenylphosphine oxide) (EuTT) with absorption spectrum less than 400 nm and high LQE (0.73) improves the external quantum efficiency of mc-Si PV module from 0.05 to 0.20, which produces a 0.42% increases in its power conversion efficiency. In addition, it is found that the enhancement brought by Eu(TTA)3(TPPO)2 can reduce cost of power generated by mc-Si devices from US$1/Wp to US$0.98/Wp according to the calculation. Therefore, Eu(TTA)3(TPPO)2 as LDS species with high LQE and low cost is promising for enhancing the performance of mc-Si PV modules in practical application.

Graphical abstractLuminescent down shifting (LDS) films doped with Eu(TTA)3(TPPO)2 (EuTT) and Eu(TTA)3Dpbt (EuTD) are prepared by soaking method and used in encapsulation of multi-crystal silicone (mc-Si) modules. Hereinto, EuTT EVA film has improved spectra response of mc-Si PV module effectively and an increase of 0.42% absolute efficiency has been obtained because of its suitable absorption spectrum, higher LQE (0.73) and no self-absorption loss while EuTD film has the absolute efficiency of mc-Si PV modules reduced by 0.28%.Figure optionsDownload full-size imageDownload high-quality image (88 K)Download as PowerPoint slideHighlights► Luminescent EVA films were prepared by soaking method for the first time. ► Eu(TTA)3(TPPO)2 was encapsulated in the pre-existing EVA layer of mc-Si modules. ► Eu(TTA)3(TPPO)2 EVA layer increases the power efficiency of mc-Si modules by 0.42%. ► Eu(TTA)3(TPPO)2 as luminescent species is promising in practical application.