Flexo-photovoltaic effect
Flexo-photovoltaic effect
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DOI：
10.1126/science.aan3256
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发表时间：
2018-05-25
期刊：
影响因子：
56.9
通讯作者：
Alexe, Marin
中科院分区：
文献类型：
--
作者：
Yang, Ming-Min;Kim, Dong Jik;Alexe, Marin
非常希望发现能够提高太阳能电池效率的光伏机制。在这里，我们报告的体积光伏效应，这是免费的热力学肖克利-奎瑟限制，但通常只表现在非中心对称（压电或铁电）材料，可以实现在任何半导体，包括硅，通过调解的挠曲电效应。我们使用原子力显微镜或微米级压痕系统来引入应变梯度，从而从钛酸锶、二氧化钛和硅的中心对称单晶中产生非常大的光伏电流。这种应变梯度诱导的体光伏效应，我们称之为挠曲光伏效应，在没有p-n结的情况下起作用。这一发现可能会通过提高现有半导体的太阳能转换效率来扩展目前的太阳能电池技术。
It is highly desirable to discover photovoltaic mechanisms that enable enhanced efficiency of solar cells. Here we report that the bulk photovoltaic effect, which is free from the thermodynamic Shockley-Queisser limit but usually manifested only in noncentrosymmetric (piezoelectric or ferroelectric) materials, can be realized in any semiconductor, including silicon, by mediation of flexoelectric effect. We used either an atomic force microscope or a micrometer-scale indentation system to introduce strain gradients, thus creating very large photovoltaic currents from centrosymmetric single crystals of strontium titanate, titanium dioxide, and silicon. This strain gradient-induced bulk photovoltaic effect, which we call the flexo-photovoltaic effect, functions in the absence of a p-n junction. This finding may extend present solar cell technologies by boosting the solar energy conversion efficiency from a wide pool of established semiconductors.