聚合物钝化钙钛矿量子点的红光放大自发辐射性能

Red amplified spontaneous emission of polymer passivated perovskite quantum dots

全无机CsPbX_(3)(X=Cl、Br、I)钙钛矿量子点具有优异的发光性能,是一种极具应用潜力的新型显示材料及激光增益介质。本文制备了发光峰位于640 nm的CsPbBr_(1.2)I_(1.8)红光量子点,在该量子点薄膜表面分别涂覆聚甲基丙烯酸甲酯(PMMA)、聚甲基丙烯酸异丁酯(PIBMA)、聚苯乙烯(PS)3种带不同功能基团的聚合物,制备了CsPbBr_(1.2)I_(1.8)/PMMA、CsPbBr_(1.2)I_(1.8)/PIBMA、CsPbBr_(1.2)I_(1.8)/PS复合薄膜,研究它们的放大自发辐射性能。结果表明,聚合物钝化一方面提升了量子点的水稳定性,另一方面,PMMA和PIBMA中的C=O钝化了量子点表面未配位的Pb^(2+),增强了量子点薄膜的光致发光强度。进一步的,在532 nm的纳秒激光泵浦下,CsPbBr_(1.2)I_(1.8)/PIBMA薄膜放大自发辐射阈值可低至81μJ·cm^(-2),稳定性也得到提升,展现了作为新型增益介质的潜力。

All-inorganic CsPbX_(3)(X=Cl,Br,I)perovskite quantum dots have excellent luminescence properties and are a new kind of display material and laser gain medium with great application potential.In this paper,CsPbBr_(1.2)I_(1.8) red quantum dots with luminescence peak at 640 nm were prepared and the CsPbBr_(1.2)I_(1.8) quantum dot films were coated with three kinds of polymers with different functional groups:polymethyl methacrylate(PMMA),polyiso-butyl methacrylate(PIBMA)and polystyrene(PS).The amplified spontaneous emission performance of CsPbBr_(1.2)I_(1.8)/PMMA,CsPbBr_(1.2)I_(1.8)/PIBMA and CsPbBr_(1.2)I_(1.8)/PS composite films were studied.The results show that the polymer passivation improves the water stability of quantum dot films.Moreover,the C=O in PMMA and PIBMA passivates the unco⁃ordinated Pb^(2+)on the surface of quantum dots,enhancing the photoluminescence intensity of QD films.Furthermore,the amplified spontaneous emission threshold of CsPbBr_(1.2)I_(1.8)/PIBMA film is as low as 81μJ·cm^(-2) under nanosecond laser pumping at 532 nm.The stability is improved,demonstrating its poten⁃tial as a novel gain medium.