In this study, we analyze the influence of the pore structure of an SBA-15 particle on the light emission from its inner adsorbed quantum dots (QDs) and outer light-emitting diode (LED) chips. It is found that the particle features of a high refractive index, comparable feature size of pore structure, and lower amount of QD adsorption help with QD light extraction, demonstrating a mechanism to suppress QD light propagating through pores and thus reducing the reabsorption loss. We consequently developed highly efficient QD white LEDs with wet-mixing QD/SBA-15 nanocomposite particles (NPs) by further optimizing the packaging methods and the introduced NP mass ratio. The LEDs demonstrated a record luminous efficacy (the ratio of luminous flux to electrical power) of 206.8 (entrusted test efficiency of 205.8 lm W–1 certificated by China National Accreditation Service) and 137.6 lm W–1 at 20 mA for white LEDs integrating only green QDs and green–red QD color convertors, respectively, with improved operating stability. These results are comparable to conventional phosphor-based white LEDs, which can be a starting point for white LEDs only using QDs as convertors toward commercialization in the near future.

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The color conversion efficiency of thin polymeric layers embedding quantum dots (QDs) is limited by their negligible light scattering ability and by the insufficient absorption of the excitation photons. In this study, a route is presented to tackle these optical shortcomings by introducing a tailored network of micropores inside these hybrid films. This is achieved by exploiting the microcellular foaming approach which is rapid, cost effective and only makes use of a green solvent (supercritical carbon dioxide). With an appropriate combination of the applied pressure and temperature during foaming, and by using a proper film thickness, the photoluminescence (PL) intensity is enhanced by a factor of up to 6.6 compared to an equivalent but unfoamed hybrid film made of CdSe/ZnS QDs in a polymethyl methacrylate matrix. Spectroscopic measurements and ray tracing simulations reveal how the porous network assists UV/blue light absorption by the QDs and the subsequent outcoupling of the converted light. The approach improves the PL for various QD concentrations and can be easily scaled up and extended to other polymeric matrices as well as light converting materials.

hence have drawn a lot of attention as down-conversion materials for white lightemitting diodes (WLEDs). [7][8][9][10] For practical applications, the cost-effectiveness, the optical performance, and the stability of PQDs should be further improved. [4] Particularly, PQDs suffer from low chemical and optical stabilities, resulting in their fast degradation under exposure to moisture, heat, and light irradiance. [11,12] Accordingly, PQDs exhibit much lower stability than conventional rare-earth-based phosphor materials. [13,14] Current research efforts therefore aim at enhancing the stability of PQDs by covering them in inorganic materials, including CdS, [15] zeolite, [16,17] glass, [18,19] CaF 2 , [20] Al 2 O 3 , [21][22][23] SiO 2 , [24][25][26][27][28][29] and TiO 2 . [30] Generally, the protective shells of PQDs are prepared using these inorganic materials by in situ synthesis. While protected PQDs with high chemical, thermal, and irradiation stabilities have been obtained, [28] the water stability of PQDs prepared with these inorganic shells still indicate a lot of room for improvement. For instance, the PL intensity of CaF 2 shell-integrated green PQDs reduces to <50% after a water-resistance test of ≈40 h. [20] Consequently, and until now, PQDs with high water stability are achieved by embedding them in enclosed organic polymer and glass matrices. [18,19,[31][32][33][34][35][36][37][38][39] The hydrophobic surface and dense polymer chains of the matrix can effectively protect the PQDs from the external environment, considerably enhancing their At present, most of lead halide perovskite quantum dots (PQDs) embedded in an enclosed organic polymer or glass matrix can achieve high water stability, yet this limits their subsequent integration with light-emitting diodes (LEDs) and other functional materials. Herein, a postadsorption process using superhydrophobic aerogel inorganic matrix (S-AIM) with open structures is presented to enhance water stability of PQDs and compose newfunctions to them such as magnetism. The CsPbBr 3 PQDs integrated with the S-AIM (AeroPQDs) exhibit a high relative photoluminescence quantum yield (PLQY, 75.6%) of 90.9% compared to pristine PQDs (PLQY, 83.2%). They preserve their initial PL intensity after 11 days of soaking in water and achieve a high relative PLQY stability (50.5%) after soaking for 3.5 months. The hydrophobic (rough) surface of the matrix, its pores with a well-matched mean diameter that promotes the homogeneous integration of PQDs and hinders the penetration of water as well as the oleophylic functional groups covering the surface of these pores are the three factors responsible for the high water stability. Finally, AeroPQDs are easily integrated with other functional nanomaterials, such as Fe 3 O 4 nanoparticles for magnetic manipulation, due to their open structure.