Perovskite quantum dots (PeQDs) have been regarded as an alternative to traditional phosphor color converters in the backlit display to improve the color gamut and rendition of LCD. However, the pending barriers of aggregation quenching and structure instability are hindering their practical applications. Herein, high-quality CsPbX3 (X = Br, Br/I) PeQDs were in situ precipitated inside glass to produce nanocomposites with superior optical performance and stability. The highest photoluminescence quantum yield (PLQY) of ∼100% for CsPbBr3@glass is ascribed to the elimination of the inner filter effect via a physical dilution approach to restore its apparent value to an intrinsic one, and the exceptional photostability and water/heat resistance are benefited from their effective isolation from the external environment by the surrounding glass network units. Employing the PeQDs@glass@PDMS monolithic film, a high-performance backlit LCD was designed, and its color gamut reached 152% of commercial LCD and 103% of NTSC, demonstrating a great potential in the optoelectronic industry.

Impurity doping is an effective approach to tuning the optoelectronic performance of host materials by imparting extrinsic electronic channels. Herein, a family of lanthanide (Ln3+) ions was successfully incorporated into a Bi:Cs2AgInCl6 lead-free double-perovskite (DP) semiconductor, expanding the spectral range from visible (Vis) to near-infrared (NIR) and improving the photoluminescence quantum yield (PLQY). After multidoping with Nd, Yb, Er and Tm, Bi/Ln:Cs2AgInCl6 yielded an ultrabroadband continuous emission spectrum with a full width at half-maximum of ~365 nm originating from intrinsic self-trapped exciton recombination and abundant 4f–4f transitions of the Ln3+ dopants. Steady-state and transient-state spectra were used to ascertain the energy transfer and emissive processes. To avoid adverse energy interactions between the various Ln3+ ions in a single DP host, a heterogeneous architecture was designed to spatially confine different Ln3+ dopants via a “DP-in-glass composite” (DiG) structure. This bottom-up strategy endowed the prepared Ln3+-doped DIG with a high PLQY of 40% (nearly three times as high as that of the multidoped DP) and superior long-term stability. Finally, a compact Vis–NIR ultrabroadband (400~2000 nm) light source was easily fabricated by coupling the DiG with a commercial UV LED chip, and this light source has promising applications in nondestructive spectroscopic analyses and multifunctional lighting.

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lasers. [1][2][3][4][5][6][7][8][9][10][11] However, the toxicity of PQDs limit their practical applications. Bivalent manganese (Mn 2+ ) doping was widely studied in semiconductor materials like CdS, ZnS, [12][13][14][15] and as identical valance with Pb 2+ in lead halide perovskite, Mn 2+ can be introduced into CsPbX 3 host by substituting Pb 2+ to reduce the usage of Pb 2+ heavy metal ions. Additionally, energy transfer (ET) from perovskite host to Mn 2+ dopants can result in extra Mn 2+ red luminescence assigned to d-d transition. [16] Compared to II-VI group semiconductors, PQDs are regarded as appropriate hosts to efficiently sensitize Mn 2+ emission benefited from their high absorption coefficient, narrow emission width, and long excited-state lifetime. [17] The primary parameter to influence energy transfer and Mn emission intensity is energy difference (ΔE g ) between bandto-band emission of PQD and 4 T 1 → 6 A 1 transition of Mn 2+ . [18] When ΔE g value (0.7-0.9 eV) is appropriate, an intense Mn emission can be obtained; however, decreasing ΔE g intensifies back transfer (BT) from doped Mn 2+ centers to the perovskite host, leading to the weakening or even disappearing of Mn 2+ luminescence. [18][19][20] CsPbCl 3 PQDs have been reported to be the ideal host for efficiently transferring excitonic energy to Mn 2+ because of their appropriate bandgap of 3.0 eV. [18] When Cl was gradually replaced by Br, the bandgap of CsPb(Cl/Br) 3 PQDs becomes smaller and ET from PQDs to Mn 2+ is inefficient, leading to weak Mn 2+ luminescence. As tabulated in Table S1 (Supporting Information), for a classic Cs-hot-injection method using PbBr 2 and MnCl 2 as the precursors, the as-prepared Mn:CsPb(Cl/Br) 3 with excitonic emission at blue region (430-480 nm) has a low PLQY (31%) and Mn 2+ emission can be barely observed; [17] for a room-temperature supersaturated crystallization method, a high-content MnCl 2 precursor is required, causing low PLQY of excitonic emission and concentration quenching of Mn 2+ luminescence. [21,22] Furthermore, Mn:CsPb(Cl/Br) 3 PQDs can also be fabricated by a postsynthetic cation exchange and the bandgap of exciton can be tuned over a wide range, but the maximal PLQY is only 28%. [23] More recently, strong Mn 2+ emission Recently, Mn 2+ -doped CsPb(Cl/Br) 3 perovskite nanocrystals (NCs), showing the advantages of dual-color emissions via exciton-to-dopant energy transfer and reduced usage of toxic Pb 2+ heavy metal ions by nontoxic Mn 2+ substitution, are widely explored. However, photoluminescence quantum yields (PLQYs) for Mn 2+ -doped CsPb(Cl/Br) 3 NCs still need to be further improved. Here, a halogen-hot-injection strategy is developed to prepare Mn:CsPb(Cl 0.6 Br 0.4 ) 3 NCs with the maximal PLQY of 65%. With this method, intense blue narrowband emission from excitonic recombination and orange broadband emission from Mn 2+ 4 T 1 → 6 A 1 transition can be simultaneously achieved. The competitive luminescence between perovskite NCs and Mn 2+ dopants is systematically investigated by contr...