Elemental de-mixing-induced epitaxial kesterite/CdS interface enabling 13%-efficiency kesterite solar cells
Elemental de-mixing-induced epitaxial kesterite/CdS interface enabling 13%-efficiency kesterite solar cells
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DOI：
10.1038/s41560-022-01132-4
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发表时间：
2022-10-06
期刊：
影响因子：
56.7
通讯作者：
Xin, Hao
中科院分区：
文献类型：
--
作者：
Gong, Yuancai;Zhu, Qiang;Xin, Hao
自2013年以来，凯斯特石太阳能电池的转换效率一直停滞不前在12.6%。与黄铜矿太阳电池相比，钾锌矿太阳电池的性能受到异质结界面复合的严重限制。在这里，我们证明了由于化学浴沉积过程中锌离子的溶解，凯斯特石/硫化镉异质结被构建在贫锌表面。Cd~(2+)在锌晶位上的占据和锌~(2+)的重新沉积形成了缺陷和晶格失配的界面。KESTRITE/CDS结的低温退火热处理促使Cd~(2+)从吸收体返回到Cd~(2+)，而锌~(2+)从吸收体体到表面，实现了梯度组成，重建了外延界面。这大大减少了接口复合，并提高了器件的开路电压和填充系数。我们实现了经过认证的12.96%的小面积(0.11厘米(2))效率和11.7%的大面积(1.1厘米(2))效率。这一发现有望推动凯斯特石太阳能电池的发展。由于控制缺陷方面的挑战，自2013年以来，凯斯特石太阳能电池的效率一直停留在12.6%。现在，Gong等人。提出了一种对Kestite/CDS结进行低温热处理以形成具有低缺陷密度的外延界面，从而实现了13%效率的器件。
The conversion efficiency of kesterite solar cells has been stagnated at 12.6% since 2013. In contrast to chalcopyrite solar cells, the performance of kesterite solar cells is seriously limited by heterojunction interface recombination. Here we demonstrate kesterite/CdS heterojunction is constructed on a Zn-poor surface due to the dissolution of Zn2+ during chemical bath deposition. The occupation of Cd2+ on the Zn site and re-deposition of Zn2+ into CdS creates a defective and lattice-mismatched interface. Low-temperature annealing of the kesterite/CdS junction drives migration of Cd2+ from absorber back to CdS and Zn2+ from absorber bulk to surface, achieving a gradient composition and reconstructing an epitaxial interface. This greatly reduces interface recombination and improves device open-circuit voltage and fill factor. We achieve certified 12.96% efficiency small-area (0.11 cm(2)) and certified 11.7% efficiency large-area (1.1 cm(2)) kesterite devices. The findings are expected to advance the development of kesterite solar cells.The efficiency of kesterite solar cells has been stuck at 12.6% since 2013 due to challenges in controlling defects. Now Gong et al. present a low-temperature annealing of the kesterite/CdS junction to form an epitaxial interface with a low defect density, enabling 13%-efficiency devices.