近年來鈣鈦礦應用於LED領域，以低成本、容易製作、高色純度、高效率而聞名，但由於3D鈣鈦礦LED因為晶體尺寸大而導致激子結合能低容易產生解離，此外表面粗糙度高容易產生缺陷造成不必要的非輻射複合，為了解決上述問題因此加入二維材料PEA作為抑制三維材料結晶的功用，可以使晶體尺寸縮小，使上述問題得到改善。
由此我們知道加入二維材料可以縮小鈣鈦礦晶體的尺寸，進而提升效率，然而為了進一步縮小鈣鈦礦結晶的尺寸，加入更多的二維材料反而導致二維材料自發性的結晶導致薄膜的相分離與表面粗糙度提高，使得電性一落千丈，為了縮小晶體尺寸又可以避免二維材料結晶，為此我們加入一種可以抑制PEA結晶的有機物冠醚，因為冠醚的加入，我們可以在加入額外的PEA情況下抑制了PEA的結晶，使得鈣鈦礦的晶體尺寸縮小而不會產生相分離，冠醚也可以使PEA更均勻的散佈在薄膜上，使得能量轉移更為順利，使效率得以提升。
最終此篇論文透過製程手法的優化，以及在10%過量PEABr的前驅液中加入1mg/ml劑量的冠醚，使PEABr與冠醚的協同作用達到最適的程度，最後鈣鈦礦LED的最大亮度達到21114 cd m−2，電流效率達到7.49 cd A-1。

In recent years, perovskite has been used in the field of LEDs and is known for its low cost, easy fabrication, high color purity, and high efficiency. However, due to the large crystal size of 3D perovskites, the exciton binding energy is low and it is easy to dissociate. In addition, the surface’s High roughness is easy to generate defects and cause non-radiative recombination. To solve the above problems, the two-dimensional perovskite material －phenethylammonium (PEA) is added to suppress the crystallization of three-dimensional perovskites, which can reduce the crystal size and improve the above problems.

From this, we know that adding two-dimensional perovskite materials(PEA) can reduce the size of perovskite crystals, thereby improving their efficiency. However, to further reduce the size of perovskite crystals, adding more two-dimensional perovskites(PEA) will lead to the spontaneous crystallization of two-dimensional perovskites(PEA), so that The phase separation of perovskite and the increase of surface roughness make the electrical properties plummet. To reduce the crystal size and avoid the crystallization of two-dimensional perovskites(PEA), we add an organic compound called crown ether that can inhibit the crystallization of PEA. Because of the addition of the crown ether, we can suppress the crystallization of PEA by adding additional PEA, so that the crystal size of the perovskite is reduced without phase separation, and the crown ether can also make the PEA spread more uniformly on the film, it makes the energy transfer more smoothly and improves the efficiency.
Finally, through the optimization of the process method and the addition of 1mg/ml crown ether to the precursor solution of 10% excess PEABr, which makes the synergistic effect of PEABr and crown ether reach the optimum level. The perovskite light-emitting diode in this work exhibits a brightness of 21444 cd m−2 and current efficiency of 7.8cd A-1.

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