鈣鈦礦奈米片：聚(N-乙烯基咔唑)奈米複合物與氧化鋅奈米柱陣列製作混成式發光元件

Abstract

本研究提出以氧化鋅奈米柱陣列(ZnO NAs)作為電子傳輸層與搭配鈣鈦礦奈米片(MAPbBr3 NPLs)發光層之新穎反結構發光元件並提升其效率。採用水熱法在ITO基板上製備垂直成長的氧化鋅奈米柱陣列以提供電子傳導路徑，且在可見光範圍400-800 nm的光穿透率高達90%以上。將乙氧基化聚乙烯亞胺（PEIE）引入到ZnO NAs和MAPbBr3 NPLs層之間以降低能障並提高電子注入效率。此外，將不同重量比的聚（N-乙烯基咔唑）（PVK）與MAPbBr3 NPLs摻混以製備均勻分散的奈米複合膜，從而提高元件的性能。同時，MAPbBr3 NPLs摻混PVK後之光致發光由於減少載子淬滅和延長載子壽命而增加。使用poly(9,9-dioctylfluorene- co-N-(4-butylphenyl)diphenylamine)(TFB)作為電洞傳輸層，製作結構為ITO/PEIE-modified ZnO NAs/MAPbBr3 NPLs:PVK/TFB/Au 之反結構發光元件。與沒有摻混PVK之元件相比，含有PVK之元件的電流密度被顯著抑制。最佳元件效果為MAPbBr3 NPLs:PVK摻混比列64:36 wt%，其最大亮度及電流效率各為495 cd/m2及0.078 cd/A，並具有3.1 V的低導通電壓，以上結果說明氧化鋅奈米柱陣列搭配鈣鈦礦奈米片具有應用於光電元件之潛力。

In this study, we propose a novel inverted perovskite light-emitting devices (PeLEDs) with zinc oxide nanorod arrays (ZnO NAs) as the electron transport layer and the luminescent layer of the methylammonium lead bromide nanoplatelets (MAPbBr3 NPLs) and enhance its efficiency. ZnO nanorods were vertically grown on the ITO substrates via the hydrothermal method to provide electron transporting paths and the transmittion in the visible light range of 400-800 nm is up to 90%. The polyethyleneimine ethoxylated (PEIE) was inserted between the ZnO NAs and the MAPbBr3 NPLs layer to reduce the energy barrier and improve the electron injection efficiency. In addition, poly(N-vinylcarbazole) (PVK) in different weight ratios were mixed with MAPbBr3 NPLs to prepare uniformly dispersed nanocomposite films, thereby improving the performance of devices. At the same time, the photoluminescence of MAPbBr3 NPLs:PVK nanocomposite film was increased due to reduced self-quenching and prolonged carrier lifetime. Inverted PeLEDs with the configuration of ITO/PEIE-modified ZnO NAs/MAPbBr3 NPLs:PVK/TFB/Au were fabricated and evaluated, using TFB as the hole transport layer. The current density of the devices containing PVK matrix was significantly suppressed compared to those without PVK. The best device effect was MAPbBr3 NPLs: PVK mixing ratio of 64:36 wt%, the max brightness of 495 cd/m2 and current efficiency of 0.078 cd / A, and a low turn-on voltage of 3.1 V that shows potential use in light-emitting applications.