Abstract Kesterite Cu 2 ZnSn( S x Se 1 − x ) 4 is an attractive earth-abundant material for low-cost thin film photovoltaics with the capability to achieve power production in the terawatt range and therefore to supply a significant part of the global electricity needs. Despite its advantageous optical and electrical properties for photovoltaic applications, the large band tailing causes voltage losses that limit the efficiency of kesterite-based devices. Here we show that the band-tailing originates mainly from band-gap fluctuations attributable to chemical composition variations at nanoscale; while electrostatic fluctuations play a lesser role. Absorption measurement reveal that the Cu-Zn disorder, always present in kesterite Cu 2 ZnSn( S x Se 1 − x ) 4 , is not the main source of the large band tailing. Instead defect clusters having a significant impact on the band-edge energies, e.g. [2 Cu Zn − + Sn Zn 2 + ], are proposed as the main origin for the kesterite band tail.

中文翻译：

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黄铜矿带尾的起源

摘要 Kesterite Cu 2 ZnSn( S x Se 1 − x ) 4 是一种极具吸引力的地球资源丰富的低成本薄膜光伏材料，能够实现太瓦级的电力生产，因此为全球大部分电力供应需要。尽管其在光伏应用中具有优势的光学和电学特性，但大波段拖尾会导致电压损失，从而限制了基于锌黄铜矿的器件的效率。在这里，我们表明带尾拖尾主要源于纳米尺度化学成分变化引起的带隙波动；而静电波动的作用较小。吸收测量表明铜锌无序，总是存在于黄铜矿Cu 2 ZnSn( S x Se 1 - x ) 4 中，不是大带拖尾的主要来源。