Enhanced energy conversion of up-conversion solar cells by the integration of compound parabolic concentrating optics
Enhanced energy conversion of up-conversion solar cells by the integration of compound parabolic concentrating optics
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DOI：
10.1016/j.solmat.2015.04.020
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发表时间：
2015-09-01
影响因子：
6.9
通讯作者：
Richards, Bryce S.
中科院分区：
文献类型：
--
作者：
Arnaoutakis, Georgios E.;Marques-Hueso, Jose;Richards, Bryce S.
上转换技术是利用亚带隙光子制作太阳能电池的有效途径。由于UC的非线性性质，太阳能电池半导体和UC材料之间的最佳激发功率状态对应于大于一个数量级的太阳能集中度的差异。这种差异可以通过集中通过太阳能电池传输的光子以增加功率密度并最大化UC发光的强度来用集成光学器件桥接。为了实现这一点，介电填充的复合抛物面聚光器（CPC）被用作平面双面硅太阳能电池背面上的集成光学器件，连同25%的Er 3+掺杂的六方晶系氟化钇钠（β-NaYF 4：Er）UC磷光体。通过首次报道的基于c-Si的上转换太阳能电池（UC-SC）的I-V特性，量化了子带隙照明下的效率从0.123%提高到0.163%，提高了32%。对于在1523 nm处以0.024 W/cm（2）的辐照度激发，获得了外量子效率（EQE）的增强，从非聚光参比UC-SC的133%到具有集成光学器件的太阳能电池的1.80%，对应于0.75 W/cm（2）的归一化EQE。这表明CPC适合于UC-SC，因为它们在正向方向上增加浓度，同时在反向方向上保持UC发射的高收集效率。此外，这种方法能够独立于太阳能电池所需的浓度来优化UC磷光体上的太阳能浓度。(C)2015作者由爱思唯尔公司出版
Up-conversion (UC) is a promising approach to utilize sub-band-gap photons for solar cells (SCs). Due to the non-linear nature of UC, the optimal excitation power regimes between the solar cell semiconductor and the UC material correspond to a difference in solar concentration of more than an order of magnitude. This difference can be bridged with integrated optics by concentrating the photons transmitted through the solar cell to increase the power density and maximize the intensity of UC luminescence. To realize this, dielectric-filled compound parabolic concentrators (CPCs) were used as integrated optics on the rear side of a planar bifacial silicon solar cell together with a 25% Er3+ doped hexagonal sodium yttrium fluoride (beta-NaYF4:Er) UC phosphor. An efficiency increase of 32% from 0.123% to 0.163% under sub-band-gap illumination is quantified by means of the first ever reported I-V characteristics for an up-conversion solar cell (UC-SC) based on c-Si. An enhancement in external quantum efficiency (EQE) is obtained from 133% for the non-concentrating reference UC-SC to 1.80% for a solar cell with integrated optics for an excitation at 1523 nm with an irradiance of 0.024 W/cm(2), corresponding to a normalized EQE of 0.75 W/cm(2). This demonstrates that CPCs are suitable for UC-SC as they increase the concentration in the forwards direction, while maintaining high collection efficiency of the UC emission in the reverse direction. In addition, such an approach enables the optimization of the solar concentration on the UC phosphor independently from the concentration required for the solar cell. (C) 2015 The Authors. Published by Elsevier B.V.