Nguyen Thang Phan, Ozturk Abdullah, Park Jongee, Sohn Woonbae, Lee Tae Hyung, Jang Ho Won, Kim Soo Young
School of Chemical Engineering and Materials Science, Chung-Ang University, Seoul, Republic of Korea.
Metallurgical and Materials Engineering Department, Middle East Technical University, Ankara, Turkey.
Sci Technol Adv Mater. 2017 Dec 18;19(1):10-17. doi: 10.1080/14686996.2017.1412231. eCollection 2018.
In this work, CsPbBr and PbSe nanocomposites were synthesized to protect perovskite material from self-enlargement during reaction. UV absorption and photoluminescence (PL) spectra indicate that the addition of Se into CsPbBr quantum dots modified the electronic structure of CsPbBr, increasing the band gap from 2.38 to 2.48 eV as the Cs:Se ratio increased to 1:3. Thus, the emission color of CsPbBr perovskite quantum dots was modified from green to blue by increasing the Se ratio in composites. According to X-ray diffraction patterns, the structure of CsPbBr quantum dots changed from cubic to orthorhombic due to the introduction of PbSe at the surface. Transmission electron microscopy and X-ray photoemission spectroscopy confirmed that the atomic distribution in CsPbBr/PbSe composite clusters is uniform and the composite materials were well formed. The PL intensity of a CsPbBr/PbSe sample with a 1:1 Cs:Se ratio maintained 50% of its initial intensity after keeping the sample for 81 h in air, while the PL intensity of CsPbBr reduced to 20% of its initial intensity. Therefore, it is considered that low amounts of Se could improve the stability of CsPbBr quantum dots.
在本工作中，合成了CsPbBr和PbSe纳米复合材料，以保护钙钛矿材料在反应过程中不发生自生长。紫外吸收光谱和光致发光（PL）光谱表明，向CsPbBr量子点中添加Se改变了CsPbBr的电子结构，随着Cs:Se比例增加到1:3，带隙从2.38 eV增加到2.48 eV。因此，通过增加复合材料中的Se比例，CsPbBr钙钛矿量子点的发射颜色从绿色变为蓝色。根据X射线衍射图谱，由于表面引入了PbSe，CsPbBr量子点的结构从立方晶系变为正交晶系。透射电子显微镜和X射线光电子能谱证实，CsPbBr/PbSe复合簇中的原子分布均匀，复合材料形成良好。在空气中将Cs:Se比例为1:1的CsPbBr/PbSe样品放置81 h后，其PL强度保持初始强度的50%，而CsPbBr的PL强度降至初始强度的20%。因此，认为少量的Se可以提高CsPbBr量子点的稳定性。
