The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P.R. China.
Nanoscale. 2018 Nov 15;10(44):20611-20617. doi: 10.1039/c8nr04986f.
Formamidinium lead bromide perovskite nanocrystals (FAPbBr3 PNCs) are extremely promising for applications in green light emitting diodes (LEDs) since their photoluminescence maxima locate in the range of 530-535 nm with a narrow full width at half-maximum (<25 nm). However, the low exciton binding energy (EB) of FAPbBr3 (∼25 meV) hinders its development in LEDs. In this study, we have developed a 2-methyl-1-pentanol assisted hot injection method for the synthesis of 2D FAPbBr3 nanoplates with high stability. Due to strong quantum confinement in two dimensions of the nanoplates, the obtained FAPbBr3 nanoplates exhibited a high EB of 168.4 meV. The high EB dramatically enhances the photoluminescence (PL) properties with a high fluorescence quantum yield of 92%, which realizes a long photoluminescence lifetime of 2 ns with negligible trapping processes. Benefiting from the high EB and outstanding PL properties, the FAPbBr3 nanoplate LED device showed a current efficiency of 17.32 cd A-1 at a low voltage of 4 V, and a corresponding external quantum efficiency (EQE) up to 4.5% with the Commission Internationale de L'Eclairage (CIE) 1931 color coordinates of (0.24, 0.73), providing a new pathway for the fabrication of efficient perovskite based LED devices.
甲脒碘化铅钙钛矿纳米晶体（FAPbBr3 PNCs）因其光致发光最大值位于 530-535nm 范围内，半峰全宽较窄（<25nm），在绿光发光二极管（LED）中具有广阔的应用前景。然而，FAPbBr3 的低激子束缚能（EB）（∼25meV）阻碍了其在 LED 中的发展。在这项研究中，我们开发了一种 2-甲基-1-戊醇辅助的热注射方法，用于合成具有高稳定性的二维 FAPbBr3 纳米板。由于纳米板的二维量子限制较强，所得的 FAPbBr3 纳米板表现出 168.4meV 的高 EB。高 EB 极大地增强了光致发光（PL）性能，荧光量子产率高达 92%，实现了无显著俘获过程的 2ns 长的光致发光寿命。得益于高 EB 和出色的 PL 性能，FAPbBr3 纳米板 LED 器件在 4V 的低电压下表现出 17.32cdA-1 的电流效率，以及高达 4.5%的相应外量子效率（EQE），色坐标为（0.24,0.73），为高效钙钛矿基 LED 器件的制备提供了新途径。
