Feasibility of Emission-Enhanced CsPbCl<sub>3</sub> Quantum Dots Co-Doped with Mn<sup>2+</sup> and Er<sup>3+</sup> as Luminescent Downshifting Layers in Crystalline Silicon Solar Modules
Pengjie Song, Shunnosuke Hase, Suling Zhao, Zheng Xu, Yoshiki Iso, Tetsuhiko Isobe
Abstract
In order to enhance the photoelectric conversion efficiencies of crystalline silicon (c-Si) solar cells, CsPbCl3 quantum dots (QDs) codoped with Mn2+ and Er3+ (CsPbCl3:Mn2+, Er3+ QDs) were mixed with ethylene–(vinyl acetate) (EVA) to form a film which was used as a luminescent down-shifting (LDS) layer. The LDS layer effectively improved the low utilization of near-ultraviolet light of c-Si solar cells. These CsPbCl3:Mn2+,Er3+ QDs were synthesized via a conventional high-temperature injection method. Mn2+ is the luminescence center, and the incorporation of Er3+ greatly enhances the luminescence intensity of Mn2+. The absolute photoluminescence quantum yield of the QDs dispersed in toluene reached 79.5% when the QDs were synthesized under the optimum conditions, that is, an injection temperature of 180 °C and Pb:Mn:Er preparation molar ratios of 6:4:4. The EVA film embedded with QDs at the optimum concentration (0.9 wt %) was used as an LDS layer for c-Si solar module. The short-circuit current (ISC) and the photoelectric conversion efficiency (η) were increased by 3.42% and 4.02%, respectively, owing to the LDS layer. Moreover, a luminescent solar concentrator (LSC) which was another application of luminescent materials was also demonstrated. For LSC, the relative changes in ISC and η by using the QDs-dispersed EVA film were +14.9% and +18.0%, respectively. These results indicate a feasible application of luminescent downshifting films in solar modules.