Metal composition influences optoelectronic quality in mixed-metal lead-tin triiodide perovskite solar absorbers
Metal composition influences optoelectronic quality in mixed-metal lead-tin triiodide perovskite solar absorbers
复制标题
DOI：
10.1039/d0ee00132e
复制
发表时间：
2020-06-01
影响因子：
32.5
通讯作者：
Snaith, Henry J.
中科院分区：
文献类型：
--
作者：
Klug, Matthew T.;Milot, Rebecca L.;Snaith, Henry J.
目前全钙钛矿多结太阳能电池的设计需要混合金属Pb-Sn组合物以实现比其纯Pb对应物可能的更窄的带隙。用混合金属Pb-Sn钙钛矿可实现的较低带隙范围还包括1.3至1.4eV的范围，这在理论上对于最大化单结器件的效率是理想的。在这里，我们通过用Sn取代0.001%至70%的Pb含量，在可实现的带隙的整个范围内检查了钙钛矿材料（（HC（NH 2）（2））（0.83）Cs-0.17）（Pb 1-ySny）I（3）家族的光电质量和光伏性能。我们发现，当Sn包括0.5%和20%之间的金属含量时，存在“缺陷”的组成范围，但是对于Sn含量在30- 50%之间，光电质量被恢复。当只有1%的Pb含量被Sn取代时，我们发现光电导、光致发光寿命和光致发光量子效率降低了至少一个数量级，这表明小浓度的Sn掺入产生陷阱位点，促进材料中的非辐射复合并限制光伏性能。虽然这些观察结果表明，在没有改善材料质量的对策的情况下，1.35和1.5 eV之间的带隙不太可能用于光电应用，但在1.33 eV或更低的情况下，高效的窄带隙吸收体材料是可能的。通过优化Sn组分为30%和50%的单结光伏器件，我们分别展示了具有1.33 eV的理想单结带隙的17.6%效率的太阳能电池和适合于全钙钛矿多结电池中的底部吸收体的18.1%效率的低带隙器件。
Current designs for all-perovskite multi-junction solar cells require mixed-metal Pb-Sn compositions to achieve narrower band gaps than are possible with their neat Pb counterparts. The lower band gap range achievable with mixed-metal Pb-Sn perovskites also encompasses the 1.3 to 1.4 eV range that is theoretically ideal for maximising the efficiency of single-junction devices. Here we examine the optoelectronic quality and photovoltaic performance of the ((HC(NH2)(2))(0.83)Cs-0.17)(Pb1-ySny)I(3)family of perovskite materials across the full range of achievable band gaps by substituting between 0.001% and 70% of the Pb content with Sn. We reveal that a compositional range of "defectiveness" exists when Sn comprises between 0.5% and 20% of the metal content, but that the optoelectronic quality is restored for Sn content between 30-50%. When only 1% of Pb content is replaced by Sn, we find that photoconductivity, photoluminescence lifetime, and photoluminescence quantum efficiency are reduced by at least an order of magnitude, which reveals that a small concentration of Sn incorporation produces trap sites that promote non-radiative recombination in the material and limit photovoltaic performance. While these observations suggest that band gaps between 1.35 and 1.5 eV are unlikely to be useful for optoelectronic applications without countermeasures to improve material quality, highly efficient narrower band gap absorber materials are possible at or below 1.33 eV. Through optimising single-junction photovoltaic devices with Sn compositions of 30% and 50%, we respectively demonstrate a 17.6% efficient solar cell with an ideal single-junction band gap of 1.33 eV and an 18.1% efficient low band gap device suitable for the bottom absorber in all-perovskite multi-junction cells.