Earth Abundant Element Cu2Zn(Sn1-xGex)S4 Nanocrystals for Tunable Band Gap Solar Cells: 6.8% Efficient Device Fabrication
Earth Abundant Element Cu2Zn(Sn1-xGex)S4 Nanocrystals for Tunable Band Gap Solar Cells: 6.8% Efficient Device Fabrication
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DOI：
10.1021/cm2002836
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发表时间：
2011-05-24
影响因子：
8.6
通讯作者：
Hillhouse, Hugh W.
中科院分区：
文献类型：
--
作者：
Ford, Grayson M.;Guo, Qijie;Hillhouse, Hugh W.
在不添加表面活性剂的条件下，以油胺为溶剂，采用间歇反应法合成了Cu 2 Zn（Sn 1-xGex）S-4纳米晶.将纳米晶体刮涂在钼衬底上，然后硒化以形成Cu 2 Zn（Sn 1-xGex）-（S，Se）（4）的致密层，然后将其用作薄膜太阳能电池中的光吸收层。纳米晶体和所得太阳能电池的带隙被证明是通过调整的Ge/（Ge+Sn）的比例的锗合成前体控制。由Cu 2 ZnGeS 4纳米晶薄膜制成的太阳能电池的功率转换效率为0.51%。然而，具有Ge/（Ge+Sn）比为0.7的Cu 2 Zn（SnxGe 1-x）S-4纳米晶体在合成为贫Cu和富Zn时产生具有6.8%的效率的器件。这一结果开启了形成Ge梯度以引导少数载流子远离高复合界面并显著提高基于CZTSSe的太阳能电池的器件效率的可能性。
Cu2Zn(Sn1-xGex)S-4 nanocrystals have been synthesized via batch reaction in oleylamine with no additional surfactants present. The nanocrystals are knife-coated on molybdenum substrates and then selenized to form a dense layer of Cu2Zn(Sn1-xGex)-(S,Se)(4), which is then used as the photoabsorbing layer in a thin film solar cell. The band gaps of the nanocrystals and the resulting solar cells are demonstrated to be controlled by adjusting the Ge/(Ge+Sn) ratio of the nanocrystal synthesis precursors. Solar cells fabricated from Cu2ZnGeS4 nanocrystal films yielded a power conversion efficiency of 0.51%. However, Cu2Zn (SnxGe1-x)S-4 nanocrystals with a Ge/(Ge+Sn) ratio 0.7 yielded devices with an efficiency of 6.8% when synthesized to be Cu-poor and Zn-rich. This result opens the possibility of forming Ge gradients to direct minority carriers away from high recombination interfaces and significantly improve the device efficiency of CZTSSe-based solar cells.