Recently, low-dimensional organic−inorganic lead halide perovskites have attracted a great deal of attention due to their outstanding tunable broadband emission, while the toxicity of lead hinders their further application in the photoelectric field.Here, we report a novel lead-free Cu(I)-based organic−inorganic perovskite-related material of a (MA) 4 Cu 2 Br 6 single crystal with zero-dimensional clusters, which is a unique Cu 2 Br 6 4− cornersharing tetrahedron dimer structure consisting of two connected tetrahedra. The single crystal displays a bright broadband green emission with a high photoluminescence with a quantum yield of ≤93%, a large Stokes shift, and a very long (microsecond) photoluminescence (PL) lifetime, resulting from self-trapped exciton emission. The direct band gap characteristic of (MA) 4 Cu 2 Br 6 was proven by density functional theory calculation, and its band gap was determined by experiments to be ∼3.87 eV. In the temperature range of 98−258 K, the PL intensity increases gradually with an increase in temperature due to the deep trapping out of strong electro-phonon coupling, while the PL decreases when the temperature increases over 258 K due to phonon scattering. It is worth mentioning that this new material has high chemical and light stability, in contrast to the lead perovskite.

Zero-dimensional lead-free organic–inorganic hybrid metal halides have drawn attention as a result of their local metal ion confinement structure and photoelectric properties. Herein, a lead-free compound of (Gua)3Cu2I5 (Gua = guanidine) with a different metal ion confinement has been discovered, which possesses a unique [Cu2I5]3– face-sharing tetrahedral dimer structure. First-principles calculation demonstrates the inherent nature of a direct band gap for (Gua)3Cu2I5, and its band gap of ∼2.98 eV was determined by experiments. Worthy of note is that (Gua)3Cu2I5 exhibits a highly efficient cool-white emission peaking at 481 nm, a full-width at half-maximum of 125 nm, a large Stokes shift, and a photoluminescence quantum efficiency of 96%, originating from self-trapped exciton emission. More importantly, (Gua)3Cu2I5 single crystals have a reversible thermoinduced luminescence characteristic due to a structural transition scaled by the electron–phonon coupling coefficients, which can be converted back and forth between cool-white and yellow color emission by heating or cooling treatment within a short time. In brief, as-synthesized (Gua)3Cu2I5 shows great potential for application both in single-component white solid-state lighting and sensitive temperature scaling.

All-inorganic metal halide materials are eye-catching because of their interesting and excellent optoelectronic properties. In this report, a series of Mn 2+ -doped CscdBr 3 perovskite materials were synthesized by grinding in a mortar. The strong photoluminescence (PL) emission band at 650 nm and its PLQY reaches 54.42% after doping with modest Mn 2+ . The enhanced PL emission is the result of a weak ferromagnetic coupling of Mn−Mn pair to form a magnetic polaron and self-trapped exciton (STE), and the energy transfer from the d−d transition of a single Mn to STE and Mn−Mn pair level is very effective. The doping also enhances the nonlinear optical response of the material by their laser excitations. The photophysical mechanism of Mn-doped CsCdBr 3 has been discussed, and the specific conversion process from the bandedge to each charge state has been analyzed in detail. This kind of material may have significant applications in spintronic or optoelectronic devices.

Zero-dimensional (0D) organic metal halides have captured extensive attention for their various structures and distinguished optical characteristics. However, achieving efficient emission through rational crystal structure design remains a great challenge, and how the crystal structure affects the photophysical properties of 0D metal halides is currently unclear. Herein, a rational crystal structure regulation strategy in 0D Sb­(III)-based metal halides is proposed to realize near-unity photoluminescence quantum yield (PLQY). Specifically, two 0D organic Sb­(III)-based compounds with different coordination configurations, namely, (C25H22P)2SbCl5 and (C25H22P)­SbCl4 (C25H22P+ = benzyltriphenylphosphonium), were successfully obtained by precisely controlling the ratio of the initial raw materials. (C25H22P)2SbCl5 adopts an octahedral coordination geometry and shows highly efficient broadband yellow emission with a PLQY of 98.6%, while (C25H22P)­SbCl4 exhibits a seesaw-shaped [SbCl4]− cluster and does not emit light under photoexcitation. Theoretical calculations reveal that, by rationally controlling the coordination structure, the indirect bandgap of (C25H22P)­SbCl4 can be converted to the direct bandgap of (C25H22P)2SbCl5, thus ultimately boosting the emission intensity. Together with efficient emission and outstanding stability of (C25H22P)2SbCl5, a high-performance white-light emitting diode (WLED) with a high luminous efficiency of 31.2 lm W–1 is demonstrated. Our findings provide a novel strategy to regulate the coordination structure of the crystals, so as to rationally optimize the luminescence properties of organic metal halides.

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One of the most appealing material systems for solar energy conversion is all‐polymer blend. Presently, the three key merits (power conversion efficiency, operation stability and mechanical robustness) exhibited a trade‐off in a particular all‐polymer blend system, which greatly limit its commercial application. Diverting the classic ternary tactic of organic solar cells based on polymer, nonfullerene small molecule and fullerene, herein we demonstrate that the three merits of a benchmark all‐polymer blend PM6:PY‐IT can be simultaneously maximized via the introduction of a polymerized fullerene derivative PPCBMB. Importantly, the addition of the guest component promoted the power conversion efficiency of PM6:PY‐IT blend from 16.59% to 18.04%. Meanwhile, the device stability and film ductility are also improved due to the addition of this polymerized fullerene material. Morphology and device physics analyses reveal that optimal ternary system contains well‐maintained molecular packing and crystallinity, being beneficial to keeping favorable charge transport and the reduced domain size contributed to charge generation and ductility improvement. Furthermore, the ternary photovoltaic blend was successfully used as photocatalysts, and an excellent heavy metal removal from water was demonstrated. This study showcases the multi‐functions of all‐polymer blends via the use of polymerized fullerenes.

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