Insight into the role of post-annealing in air for high efficient Cu2ZnSn(S,Se)4 solar cells
Insight into the role of post-annealing in air for high efficient Cu2ZnSn(S,Se)4 solar cells
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深入了解空气中后退火对高效 Cu2ZnSn(S,Se)4 太阳能电池的作用
DOI：
10.1016/j.solmat.2018.03.029
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发表时间：
2018-08-01
影响因子：
6.9
通讯作者：
Sun, Yun
中科院分区：
文献类型：
--
作者：
Gao, Shoushuai;Zhang, Yi;Sun, Yun
通过在空气中在270 ℃下对整个器件退火3 min，显著改善了Cu 2 ZnSn（S，Se）（4）（CZTSSe）太阳能电池的器件性能。通过对太阳电池的外量子效率（EQE）、拉曼光谱、电容电压（C-V）、导纳谱（AS）的测量结果以及数值模拟的分析，提出了后退火处理提高太阳电池性能的原因。实验结果表明，退火后，吸收体表面的主要自由空穴由深缺陷Cu-Zn转变为浅缺陷V-Cu，导致吸收体表面[V-Cu + Zn-Cu]缺陷团密度增加，[2Cu（Zn）+ Sn-Zn]缺陷团密度降低。结果，开路电压（V-oc）和填充因子（FF）显著增加。短路电流密度（J（sc））略有增加，这可能是由于CdS/CZTSSe界面复合减少，能带排列改善。因此，CZTSSe太阳能电池的转换效率从4.41%提高到8.02%，通过后退火的完整的设备。此外，使用wxAMPS软件的数值模拟进行揭示洞察的缺陷类型，缺陷密度和载流子密度的变化后退火处理的作用。
The device performance of Cu2ZnSn(S,Se)(4) (CZTSSe) solar cells are improved significantly by annealing the full devices at 270 degrees C for 3 min in air. This paper proposes the origin of the improvement of solar cell by post annealing treatment by analyzing the results of external quantum efficiency (EQE), Raman spectra, capacitance voltage (C-V), admittance spectra (AS) measurements, and numerical simulation. The experimental results show that the dominant free hole carriers changed from deep defect Cu-zn to the much higher density of shallow defect V-cu after annealing process, which resulting the increase of density of benign [V-cu + Zn-cu] defect cluster, and the decrease of density of detrimental [2Cu(Zn) + Sn-Zn] defect cluster in the surface region of absorber. As a result, the open voltage (V-oc) and fill factor (FF) increase significantly. The short circuit current density (J(sc)) increases slightly, which can be attributed to the decrease of interface recombination as well as the improvement of band alignment at CdS/CZTSSe interface. As a consequence, the conversion efficiency of CZTSSe solar cell is improved from 4.41% to 8.02% by post-annealing the full device. Additionally, numerical simulations using wxAMPS software are conducted to reveal insight into the role of the changes of defect type, defect density, and carrier density by post-annealing treatment.