Highly luminescent red emissive perovskite quantum dots-embedded composite films: ligands capping and caesium doping-controlled crystallization processElectronic supplementary information (ESI) available: Additional absorption spectrum of composite and time-resolved measurements, photoluminescence spectrum of Cs0.2FA0.8PbI3·DPPA/PVDF films. See DOI: 10.1039/c8nr10036e

• Main Authors: Wu, Xian-gang, Tang, Jialun, Jiang, Feng, Zhu, Xiaoxiu, Zhang, Yanliang, Han, Dengbao, Wang, Lingxue, Zhong, Haizheng
• Format: Article
• Language: English
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c8nr10036e

Perovskite quantum dots (PQDs) are emerging as functional luminescence down-shifting materials for light conversion applications. The incorporation of PQDs into a polymeric matrix is a key step to improving their stability, thus facilitating device integration. Compared to the conventional way of mixing the pre-synthesized PQDs into a polymer, the in situ fabrication of perovskite quantum dots-embedded composite films (PQDCFs) is an efficient and cost-effective method, which yields enhanced photoluminescence properties. This method has been successfully developed for green emissive CH 3 NH 3 PbBr 3 PQDCFs, whereas the red CH 3 NH 3 PbI 3 PQDCFs only show the photoluminescence quantum yields (PLQYs) less than 15%. By means of combining transmittance electron microscopy (TEM) and absorption spectrum analysis, we showed that the "perovskite red wall" in PQDCFs was mainly related to the phase separation, formation of large-sized particles and incomplete chemical conversion of precursors. These problems are caused by the solubility variance of perovskite precursors in the solvent as well as the solvation compatibility between perovskite precursors and the polymer during the crystallization process. Based on these findings, we introduced Cs + as a dopant and 3,3-diphenylpropyamine (DPPA) as capping ligands, respectively, to decrease the solubility variance of the precursors and improve the compatibility between PQDs and the polymer. Consequently, highly luminescent red emissive PQDCFs with a PLQY of 91% were achieved with this strategy. A ligand and Cs + were introduced to reduce the solubility between precursors and polymers, resulting in highly luminescent composite films.