Breaking the Open-Circuit Voltage Deficit Floor in PbS Quantum Dot Solar Cells through Synergistic Ligand and Architecture Engineering
Breaking the Open-Circuit Voltage Deficit Floor in PbS Quantum Dot Solar Cells through Synergistic Ligand and Architecture Engineering
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DOI：
10.1021/acsenergylett.7b00244
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发表时间：
2017-06-01
影响因子：
22
通讯作者：
Konstantatos, Gerasimos
中科院分区：
文献类型：
--
作者：
Pradhan, Santanu;Stavrinadis, Alexandros;Konstantatos, Gerasimos
为了充分发挥胶体量子点（CQD）太阳能电池的潜力，解决大开路电压（V-OC）赤字问题是实现更高效率的主要障碍。这些太阳能电池中Voc缺陷的来源主要在于量子点的亚带隙陷阱态的存在。在这里，我们提出了一个协同工程框架，通过化学表面钝化和利用配体和结构工程的远程钝化来钝化PbS量子点中的这些亚带隙态。特别是，我们通过将PbS量子点与ZnO纳米晶体混合，并结合混合配体处理来钝化表面陷阱，形成了大块纳米异质结（BNH）。我们采用碘化锌和3-巯基丙酸的混合配体体系来利用有机和无机配体在表面钝化和改善电荷传输方面的优势。在BNH结构中，这种混合配体处理导致PbS量子点的Voc亏缺达到了创纪录的0.4-0.55 V，而之前报道的1.1-1.35 eV带隙PbS量子点的Voc亏缺为0.6-0.8 V。
To realize the full potential of colloidal quantum dot (CQD) based solar cells, it is important to address the issue of large open-circuit voltage (V-OC) deficit which is a major roadblock in reaching higher efficiencies. The origin of the Voc deficit in these solar cells lies primarily in the presence of sub-bandgap trap states of the QDs. Here, we present a synergistic engineering framework to passivate these sub-bandgap states in PbS QDs through chemical surface passivation and remote passivation exploiting ligand and architecture engineering. In particular, we form bulk nanoheterojunctions (BNH) by mixing PbS QDs with ZnO nanocrystals in conjunction with mixed ligand treatments to passivate surface traps. We employ the mixed ligand system of zinc iodide and 3-mercatopropyonic acid to leverage the benefits of both organic and inorganic ligands for surface passivation and improved charge transport. This mixed ligand treatment in BNH architectures leads to record low Voc deficit for PbS QDs of 0.4-0.55 V compared to previously reported 0.6-0.8 V for the range of 1.1-1.35 eV bandgap PbS QDs.