Surface Doping Boosts Triplet Generation Yield in Perovskite-Sensitized Upconversion
Surface Doping Boosts Triplet Generation Yield in Perovskite-Sensitized Upconversion
复制标题
表面掺杂提高钙钛矿敏化上转换中的三重态产率
DOI：
10.1002/adom.202201921
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发表时间：
2022-10-30
影响因子：
9
通讯作者：
Nienhaus, Lea
中科院分区：
文献类型：
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作者：
Sullivan, Colette M.;Bieber, Alexander S.;Nienhaus, Lea
基于三重态-三重态湮灭的光子上转换（TTA-UC）可以在低相对注量下有效地产生更高能量的光子。块体金属卤化物钙钛矿在有效敏化固态中的分子三线态方面提供了希望，这是将TTA-UC集成到基于器件的应用中所必需的。最近的工作集中在TTA-UC从红荧烯三重态湮灭剂敏化钙钛矿薄膜已经建立了相对有效的电荷提取钙钛矿，形成三重态激子红荧烯。然而，在钙钛矿/红荧烯界面处的电荷转移的具体细节尚未完全阐明。为了提高器件性能并研究界面电荷转移的性质，探索了各种有机溶剂来处理钙钛矿表面。扫描隧道显微镜和光谱显示电子能带结构的差异，其中根据所使用的溶剂观察到n型和p型终止的钙钛矿表面。在光谱学的支持下，监测了钙钛矿电子结构的影响，表明n型钙钛矿敏化剂具有更高的TTA-UC效率，这是由于有利的能带弯曲导致有效的空穴介导的三重态形成。总的来说，通过溶剂处理的钙钛矿敏化剂的电子结构的调谐被示出为在调谐有效的三重态生成的机制中的关键力量。
Triplet-triplet annihilation-based photon upconversion (TTA-UC) can efficiently generate higher energy photons at low relative fluences. Bulk metal halide perovskites have offered promise in efficiently sensitizing molecular triplet states in the solid state, necessary for the integration of TTA-UC into device-based applications. Recent work focused on TTA-UC from a rubrene triplet annihilator sensitized by perovskite thin films has established relatively efficient charge extraction from the perovskite, forming the triplet exciton in rubrene. Yet, the specifics underpinning charge transfer at the perovskite/rubrene interface are not fully elucidated. To improve device performance and study the properties governing charge transfer at the interface, various organic solvents are explored to treat the perovskite surface. Scanning tunneling microscopy and spectroscopy show a difference in the electronic band structure, where both n- and p-type terminated perovskite surfaces are observed depending on the solvent used. Supported by optical spectroscopy, the impact of the perovskite electronic structure is monitored, indicating that n-type perovskite sensitizers feature higher TTA-UC efficiencies due to favorable band bending resulting in efficient hole-mediated triplet formation. Overall, the tuning of the electronic structure of the perovskite sensitizer through solvent treatment is shown to be a key force in tuning the mechanism of efficient triplet generation.