Abstract Hybrid materials combining a wide bandgap metal oxide semiconductor, metal chalcogenide nanocrystals and molecular systems represent very attractive materials for fabricating devices with new function or improved photoelectrochemical performance. This study deals with sensitization of NiO, which is a p-type semiconductor, by quantum dots (QDs) of PbS with an average diameter of 3 nm. The PbS QDs were attached to the monocrystalline film of NiO by mercaptopropionic acid linker and were subsequently capped with methyl-pyridine naphthalene diimide (NDI) units to prepare quantum dot sensitized solar cells (p-QDSSCs) on NiO electrodes. Time-resolved photoluminescence measurements of the PbS emission were used to determine the rate constants for charge transfer from the PbS exciton to the NiO, cobalt based redox mediator and NDI. Notably, it was shown that NDI quenches the PbS exciton by electron transfer with a quite fast rate constant (6.9 × 107 s−1). The PbS QDs sensitized NiO films were finally used to fabricate solar cells with tris(4,4′-ditert-butyl-2,2′-bipyridine) cobalt(III/II) as redox mediator. It was observed that the presence of NDI on PbS improved the photovoltaic performance by 50% relative to that of cells without NDI, leading to a device with the following characteristics: Jsc = 5.75 mA/cm2, Voc = 226 mV, ff = 34% and PCE = 0.44%. This study demonstrates that photogalvanic processes can be a productive pathway to better performing sensitized p-type semiconductor for p-QDSSC. In other words, photoinduced electron transfer from the QDs towards the electrolyte rather than initial photoinduced charge injection into the p-type semiconductor can be a favorable operative mechanism in QD sensitized NiO films and might be exploited further for the construction of better performing solar cells or photocatalytic devices.

中文翻译：

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提高 PbS 量子点敏化 NiO 光电阴极的效率，其中萘二亚胺电子受体结合到纳米晶体表面

摘要 结合宽带隙金属氧化物半导体、金属硫属化物纳米晶体和分子系统的混合材料代表了非常有吸引力的材料，用于制造具有新功能或改进的光电化学性能的器件。本研究涉及通过平均直径为 3 nm 的 PbS 量子点 (QD) 对 p 型半导体 NiO 进行敏化。PbS QDs 通过巯基丙酸连接体连接到 NiO 单晶膜上，随后用甲基吡啶萘二亚胺 (NDI) 单元覆盖，以在 NiO 电极上制备量子点敏化太阳能电池 (p-QDSSCs)。PbS 发射的时间分辨光致发光测量用于确定电荷从 PbS 激子转移到 NiO、钴基氧化还原介质和 NDI 的速率常数。尤其，结果表明，NDI 通过电子转移以非常快的速率常数（6.9 × 107 s-1）淬灭 PbS 激子。PbS QDs 敏化的 NiO 薄膜最终用于制造以三（4,4'-二叔丁基-2,2'-联吡啶）钴（III/II）作为氧化还原介质的太阳能电池。据观察，与没有 NDI 的电池相比，PbS 上 NDI 的存在将光伏性能提高了 50%，导致器件具有以下特性：Jsc = 5.75 mA/cm2，Voc = 226 mV，ff = 34%和 PCE = 0.44%。这项研究表明，光电流过程可以成为更好地为 p-QDSSC 提供敏化 p 型半导体的有效途径。换句话说，