Chen Jianian, Zhong Qixuan, Sirotti Elise, Zhou Guanda, Wolz Lukas, Streibel Verena, Dittloff Johannes, Eichhorn Johanna, Ji Yongqiang, Zhao Lichen, Zhu Rui, Sharp Ian D
Walter Schottky Institute, Technical University of Munich, Am Coulombwall 4, 85748 Garching, Germany.
Physics Department, TUM School of Natural Sciences, Technical University of Munich, Am Coulombwall 4, 85748 Garching, Germany.
ACS Nano. 2024 Dec 10;18(49):33348-33358. doi: 10.1021/acsnano.4c07621. Epub 2024 Nov 27.
AgBiS quantum dots (ABS QDs) have emerged as highly promising candidates for photovoltaic applications due to their strong sunlight absorption, nontoxicity, and elemental availability. Nevertheless, the efficiencies of ABS solar cells currently fall far short of their thermodynamic limits due in large part to sluggish charge transport characteristics in nanocrystal-derived films. In this study, we overcome this limitation by tuning the surfaces of ABS semiconductor QDs via a solvent-induced ligand exchange (SILE) strategy and provide key insights into the role of surface composition on both - and -type charge transfer doping, as well as long-range charge transport. Using this approach, the electronic properties of ABS films were systematically modulated, thereby enabling the design of planar - heterojunctions featuring favorable band alignment for solar cell applications. Carrier transport and separation are significantly enhanced by the built-in electric fields generated within the ultrathin (30 nm) ABS heterojunction absorber layers, resulting in a notable solar-cell power conversion efficiency of 7.43%. Overall, this study presents a systematic and straightforward strategy to tune not only the surfaces of ABS, but also the electronic properties of solid-state films, thereby enabling junction engineering for the development of advanced semiconductor structures tailored for photovoltaic applications.
由于其强烈的阳光吸收能力、无毒特性以及元素可用性，卤化银铋量子点（AgBiS量子点，ABS QDs）已成为光伏应用中极具潜力的候选材料。然而，目前ABS太阳能电池的效率远低于其热力学极限，这在很大程度上归因于纳米晶衍生薄膜中缓慢的电荷传输特性。在本研究中，我们通过溶剂诱导配体交换（SILE）策略调整ABS半导体量子点的表面，克服了这一限制，并深入了解了表面组成在n型和p型电荷转移掺杂以及长程电荷传输中的作用。使用这种方法，我们系统地调制了ABS薄膜的电子特性，从而实现了具有有利于太阳能电池应用的能带排列的平面p-n异质结的设计。超薄（30纳米）ABS异质结吸收层内产生的内建电场显著增强了载流子传输和分离，从而实现了7.43%的显著太阳能电池功率转换效率。总体而言，本研究提出了一种系统且直接的策略，不仅可以调整ABS的表面，还可以调整固态薄膜的电子特性，从而实现用于开发适用于光伏应用的先进半导体结构的结工程。
