With the inherent organic–metal system property, phosphorescent organic light‐emitting diodes (PhOLEDs) are capable of exhibiting high performance. However, the existence of unintended triplet–triplet annihilation (TTA), which is mainly originated from high triplet exciton density leading to inferior device performance, is a current predicament. For mitigating the TTA in devices, reported herein is an effective host system with the role of precisely controlling the triplet excitons via the multichannel processes, in which a bipolar host material, a hole‐transporting material, and an electron‐transporting material are mixed to manage the triplet exciton transfer. The mixed‐host with so‐called “triplet excitons harvesting” strategy exhibits two concomitant reverse intersystem crossing (RISC) processes that simultaneously occur in the bipolar host material:electron‐transporting material and the host‐transporting material:electron‐transporting material exciplexes, respectively. Highly efficient green and red PhOLEDs are demonstrated by these multichannel processes, in which phosphorescent emitters bis(2‐phenylpyridine) (acetylacetonate) iridium(III) (Ir(ppy)2(acac)) and bis(2‐methyldibenzo[f,h]‐quinoxaline) (acetylacetonate) iridium(III) (Ir(MDQ)2(acac)) are doped into the mixed‐host, respectively. The green and red PhOLEDs realize nearly 30% of maximum external quantum efficiencies of 29.4% and 29.2%, respectively, and also maintain 29.1% and 28.3% at 1000 cd m−2. These excellent efficiencies and low roll‐offs confirm that the concomitant RISC processes effectively manage and utilize triplet excitons.

Metal halide perovskites are ideal candidates for indoor photovoltaics (IPVs) because of their easy‐to‐adjust bandgaps, which can be designed to cover the spectrum of any artificial light source. However, the serious non‐radiative carrier recombination under low light illumination restrains the application of perovskite‐based IPVs (PIPVs). Herein, polar molecules of amino naphthalene sulfonates are employed to functionalize the TiO2 substrate, anchoring the CsPbI3 perovskite crystal grains with a strong ion–dipole interaction between the molecule‐level polar interlayer and the ionic perovskite film. The resulting high‐quality CsPbI3 films with the merit of defect‐immunity and large shunt resistance under low light conditions enable the corresponding PIPVs with an indoor power conversion efficiency of up to 41.2% (Pin: 334.11 µW cm−2, Pout: 137.66 µW cm−2) under illumination from a commonly used indoor light‐emitting diode light source (2956 K, 1062 lux). Furthermore, the device also achieves efficiencies of 29.45% (Pout: 9.80 µW cm−2) and 32.54% (Pout: 54.34 µW cm−2) at 106 (Pin: 33.84 µW cm−2) and 522 lux (Pin: 168.21 µW cm−2), respectively.

Multi-layer p-stacked emitters based on spatially confined donor/acceptor/donor (D/A/D) patterns have been developed to achieve high-efficiency thermally activated delayed fluorescence (TADF). In this case, dual donor moieties and a single acceptor moiety are introduced to form two threedimensional (3D) emitters, DM-BD1 and DM-BD2, which rely on spatial charge transfer (CT). Owing to the enforced face-to-face D/A/D pattern, effective CT interactions are realized, which lead to high photoluminescence quantum yields (PLQYs) of 94.2 % and 92.8 % for the two molecules, respectively. The resulting emitters exhibit small singlet-triplet energy splitting (DE ST) and fast reverse intersystem crossing (RISC) processes. Maximum external quantum efficiencies (EQEs) of 28.0 % and 26.6 % were realized for devices based on DM-BD1 and DM-BD2, respectively, which are higher than those of their D/A-type analogues.

Remote functionalization reactions have the power to transform a C−H (or C−C) bond at a distant position from a functional group. In the past few years, this strategy started to be practiced for the construction of versatile organofluorine compounds, such as remote fluorination, trifluoromethylation, difluoromethylation, trifluoromethylthiolation, and fluoroalkenation reactions. In this context, this Review aims to highlight key representative advances and breakthroughs in remote fluorination and fluoroalkyl(thiol)ation reactions with a particular emphasis on the control of reactivity and selectivity. For more details see the Review by I. Marek, F.‐G. Zhang, et al. on page 15378 ff.