The ultrathin PEALD-GaN surface/interface layer-modulated charge dynamics in quantum dot-sensitized solar cells
The ultrathin PEALD-GaN surface/interface layer-modulated charge dynamics in quantum dot-sensitized solar cells
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DOI：
10.1016/j.ceramint.2023.04.028
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发表时间：
2023-05-25
影响因子：
5.2
通讯作者：
Zheng，Xinhe
中科院分区：
文献类型：
--
作者：
Qiu，Peng;Wei，Huiyun;Zheng，Xinhe
在这项工作中，首次采用氮化镓（GaN）来调制量子点敏化太阳能电池（QDSC）的电荷动力学。通过等离子体增强原子层沉积 (PEALD) 方法，在 240°C 的温度下，在介孔 TiO2 光阳极和量子点 (QD) 的表面涂覆了超薄 GaN 层。结果表明，所制备的 TiO2 薄膜、GaN 层和 QD 之间存在阶梯式能级排列，加速了光生电子的提取和收集。同时，受益于PEALD的自限反应，形成II型核壳QD/GaN结构，导致光吸收增强和吸收边红移。此外，致密的GaN层还可以有效抑制光生电子从TiO2到QDs或电解质的反向转移，同时改善TiO2和QDs之间的连接。最终，即使填充因子降低，具有 0.68 nm 厚 GaN 层的 QDSC 也能将短路电流密度提高 29%，并提高器件效率。这项工作展示了 GaN 在调节 QDSC 电荷动力学方面的多功能性，以及替代 TiO2 作为电子提取和传输光电阳极的潜在优势。
In this work, gallium nitride (GaN) is employed for the first time to modulate the charge dynamics of quantum dot-sensitized solar cells (QDSCs). An ultrathin GaN layer has been coated on the surface of both mesoporous TiO2photoanode and quantum dots (QDs) at 240 °C by plasma-enhanced atomic layer deposition (PEALD) approach. It is revealed that there exists a stepped energy level alignment among the as-prepared TiO2film, GaN layer and QDs, which accelerates the extraction and collection of photogenerated electrons. Meanwhile, a type-II core-shell QD/GaN structure is formed benefiting from the self-limiting reactions of PEALD, resulting in an enhanced light absorption and a redshift of absorption edge. In addition, the dense GaN layer can also effectively inhibit the reverse transfer of photogenerated electrons from TiO2to QDs or electrolyte while improving the connection between TiO2and QDs. Ultimately, the QDSCs with a 0.68 nm-thick GaN layer achieve a 29% increase of short-circuit current density and enhanced device efficiency, even with reduced fill factor. This work has shown the multi-functions of GaN in regulating the charge dynamics of QDSCs as well as the potential advantages in replacing TiO2as photoanode for electronic extraction and transport.