Highly Efficient LiYF4:Yb3+, Er3+ Upconversion Single Crystal under Solar Cell Spectrum Excitation and Photovoltaic Application

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• 作者：Xu Chen ; Wen Xu ; Hongwei Song ; Cong Chen ; Haiping Xia ; Yongsheng Zhu ; Donglei Zhou ; Shaobo Cui ; Qilin Dai ; Jiazhong Zhang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：April 13, 2016
• 年：2016
• 卷：8
• 期：14
• 页码：9071-9079
• 全文大小：569K
• 年卷期：0
• ISSN：1944-8252

文摘

Luminescent upconversion is a promising way to harvest near-infrared (NIR) sunlight and transforms it into visible light that can be directly absorbed by active materials of solar cells and improve their power conversion efficiency (PCE). However, it is still a great challenge to effectively improve the PCE of solar cells with the assistance of upconversion. In this work, we demonstrate the application of the transparent LiYF₄:Yb³⁺, Er³⁺ single crystal as an independent luminescent upconverter to improve the PCE of perovskite solar cells. The LiYF₄:Yb³⁺, Er³⁺ single crystal is prepared by an improved Bridgman method, and its internal quantum efficiency approached to 5.72% under 6.2 W cm^–2 980 nm excitation. The power-dependent upconversion luminescence indicated that under the excitation of simulated sunlight the ⁴F_9/2–⁴I_15/2 red emission originally results from the cooperation of a 1540 nm photon and a 980 nm photon. Furthermore, when the single crystal is placed in front of the perovskite solar cells, the PCE is enhanced by 7.9% under the irradiation of simulated sunlight by 7–8 solar constants. This work implies the upconverter not only can serve as proof of principle for improving PCE of solar cells but also is helpful to practical application.