Metal halide perovskite quantum dots (PQDs) are considered as promising candidate for the next generation optoelectronic applications. However, their development is severely restricted by their poor stability. Here, we demonstrate the in situ growth of PQDs in the ordered channels of functionalized covalent-organic frameworks (COFs). The strong S-Pb chemical binding firmly anchors the PQDs in COF matrix, which prevent the aggregation of PQDs and eliminate the nonradiative trap centers of PQDs, leading to the high photoluminescence quantum yield (81.5 %) and remarkable stability. Femtosecond transient absorption spectroscopy reveal the elimination of nonradiative trap centers in PQD@COFs. Theoretical simulation results demonstrate the strong waveguide effect in PQD@COFs, which reduces the reabsorption loss. Further, the obtained white light-emitting diode exhibits ultrahigh luminous efficiency of 89.6 lm/W and excellent operating stability, which paves the way for the commercial application of PQDs.
Jiejun Ren,Andries Meijerink,Xiaopeng Zhou,Jiapeng Wu,Gangyi Zhang,Yuhua Wang
All-inorganic perovskite quantum dots (PQDs), which possess outstanding photophysical properties, are regarded as promising materials for optoelectronic applications. However, the poor light conversion efficiency and severe stability problem hinder their widespread applications. In this work, a novel encapsulation strategy is developed through the in situ growth of CsPbX3 PQDs in presynthesized mesoporous cerium-based metal organic frameworks (Ce-MOFs) and further silane hydrolysis–encapsulation, generating stable CsPbX3@Ce-MOF@SiO2 composites with greatly enhanced light conversion efficiency. Moreover, the simulation results suggest that the pore boundary of Ce-MOFs has a strong waveguide effect on the incident PQD light, constraining PQD light inside the bodies of Ce-MOFs and suppressing reabsorption losses, thus increasing the overall light conversion efficiency of PQDs. Meanwhile, the Ce-MOF@SiO2 protective shell effectively improves the stability by blocking internally embedded PQDs from the harmful external environment. Further, the obtained white-light-emitting diode shows an ultrahigh luminous efficiency of 87.8 lm/W, which demonstrates their great potential in optoelectronic applications.
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