Passivation engineering via silica-encapsulated quantum dots for highly sensitive photodetection,Carbon Energy

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Passivation engineering via silica-encapsulated quantum dots for highly sensitive photodetection
Carbon Energy ( IF 19.5 ) Pub Date : 2023-02-27 , DOI: 10.1002/cey2.350
Ji Yun Chun ₁ , Byung Gi Kim ₁ , Jin Young Kim ₁ , Woongsik Jang ₁ , Dong Hwan Wang ₁

Affiliation

Organometal halide perovskites are promising semiconducting materials for photodetectors because of their favorable optoelectrical properties. Although nanoscale perovskite materials such as quantum dots (QDs) show novel behavior, they have intrinsic stability issues. In this study, an effectively silane barrier-capped quantum dot (QD@APDEMS) is thinly applied onto a bulk perovskite photosensitive layer for use in photodetectors. QD@APDEMS is synthesized with a silane ligand with hydrophobic CH₃-terminal groups, resulting in excellent dispersibility and durability to enable effective coating. The introduction of the QD@APDEMS layer results in the formation of a low-defect perovskite film with enlarged grains. This is attributed to the grain boundary interconnection effect via interaction between the functional groups of QD@APDEMS and uncoordinated Pb²⁺ in grain boundaries. By passivating the grain boundaries, where various trap sites are distributed, hole charge-carrier injection and shunt leakage can be suppressed. Also, from the energy point of view, the deep highest occupied molecular orbital (HOMO) level of QD@APDEMS can work as a hole charge injection barrier. Improved charge dynamics (generation, transfer, and recombination properties) and reduced trap density of QD@APDEMS are demonstrated. When this perovskite film is used in a photodetector, the device performance (especially the detectivity) stands out among existing perovskites evaluated for energy sensing device applications.

中文翻译：

通过二氧化硅封装量子点进行钝化工程，实现高灵敏度光电检测

有机金属卤化物钙钛矿由于其良好的光电特性而成为光电探测器有前途的半导体材料。尽管量子点（QD）等纳米级钙钛矿材料表现出新颖的行为，但它们存在固有的稳定性问题。在这项研究中，有效的硅烷势垒封端量子点（QD@APDEMS）被薄薄地涂在块状钙钛矿感光层上，用于光电探测器。_{QD@APDEMS 由具有疏水性 CH 3}的硅烷配体合成-端基，具有优异的分散性和耐久性，可实现有效的涂层。QD@APDEMS层的引入导致形成晶粒增大的低缺陷钙钛矿薄膜。这归因于 QD@APDEMS 的官能团与不配位的 Pb ^{2+之间相互作用产生的晶界互连效应}在晶界。通过钝化分布有各种陷阱位点的晶界，可以抑制空穴载流子注入和分流泄漏。此外，从能量的角度来看，QD@APDEMS的深层最高占据分子轨道（HOMO）能级可以作为空穴电荷注入势垒。证明了 QD@APDEMS 改善了电荷动力学（生成、转移和复合特性）并降低了陷阱密度。当这种钙钛矿薄膜用于光电探测器时，其器件性能（尤其是探测率）在能量传感器件应用评估的现有钙钛矿中脱颖而出。

更新日期：2023-02-27

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