The design and synthesis of three-dimensional covalent organic frameworks (3D COFs) have still been considered as a big challenge. Here we report the design and synthesis of an AIEgen-based 3D COF (3D-TPE-COF), with a high surface area (1084 m² g⁻¹). According to powder X-ray diffraction and continuous rotation electron diffraction analyses, 3D-TPE-COF is identified to adopt a seven-fold interpenetrated pts topology. Interestingly, 3D-TPE-COF emits yellow fluorescence upon excitation, with a photoluminescence quantum yield of 20%. Moreover, by simply coating 3D-TPE-COF onto a commercial blue light-emitting diode (LED), a prototype white LED (WLED) under continuously driving without degradation for 1200 h was demonstrated. The present work suggests the possibility of using COF materials for stable WLEDs, which will greatly inspire us to design and synthesize fluorescent 3D COFs and facilitate the development of COF-based WLEDs in future.

Tungsten oxide $\left({\text{WO}}_3\right)$ was inserted as an anode interfacial layer between the photoactive layer and top electrode in inverted polymer solar cells (PSCs) with nanocrystalline titanium dioxide as an electron selective layer. The device with ${\text{WO}}_3$ exhibited a remarkable improvement in power conversion efficiency compared with that without ${\text{WO}}_3$ , which indicated that ${\text{WO}}_3$ efficiently prevented the recombination of charge carriers at the organic/top electrode interface. The dependence of the device performances on ${\text{WO}}_3$ film thickness and different top metal electrodes was investigated. Transparent inverted PSCs with thermally evaporable $\text{Ag}/{\text{WO}}_3$ as a transparent anode were also investigated when introducing a ${\text{WO}}_3$ buffer layer.

Although numerous thermally activated delayed fluorescence (TADF) organic light‐emitting diodes (OLEDs) have been demonstrated, efficient blue or even sky‐blue TADF‐based nondoped solution‐processed devices are still very rare. Herein, through‐space charge transfer (TSCT) and through‐bond charge transfer (TBCT) effects are skillfully incorporated, as well as the multi‐(donor/acceptor) characteristic, into one molecule. The former allows this material to show small singlet–triplet energy splitting (ΔE_ST) and a high transition dipole moment. The latter, on the one hand, further lights up multichannel reverse intersystem crossing (RISC) to increase triplet exciton utilization via degenerating molecular orbitals. On the other hand, the nature of the molecular twisted structure effectively suppresses intermolecular packing to obtain high photoluminescence quantum yield (PLQY) in neat flims. Consequently, using this design strategy, T‐CNDF‐T‐tCz containing three donor and three acceptor units, successfully realizes a small ΔE_ST (≈0.03 eV) and a high PLQY (≈0.76) at the same time; hence the nondoped solution‐processed sky‐blue TADF‐OLED displays record‐breaking efficiency among the solution process‐based nondoped sky‐blue OLEDs, with high brightness over 5200 cd m⁻² and external quantum efficiency up to 21.0%.

Molybdenum trioxide (MoO3) was inserted between the active layer and top electrode in inverted polymer solar cells (PSCs) with nanocrystalline titanium dioxide as an electron selective layer. The performances of structurally identical PSCs with different top electrodes (Au, Ag, and Al) were investigated and compared. The interface between MoO3 and different metals was studied by x-ray photoelectron spectroscopy. The results showed that the performances of devices with different metals are greatly improved due to the incorporation of MoO3 and the open-circuit voltage of devices is relatively insensitive to the choice of the anode metal when MoO3 is introduced.

We have developed two new carbazole-dendronized emitters based on a green emissive thermally activated delayed fluorescence (TADF) core. Both dendrimers possess excellent thermal stability, good solution processability, and an obvious TADF feature. Non-doped OLEDs based on the emitters formed by a solution process exhibit a maximum external quantum efficiency (EQE) of 13.8%. Remarkably, the EQE remains as high as 13.3% at the high luminance of 1000 cd m⁻². To the best of our knowledge, this is one of the highest EQE values for dendrimer-based fluorescent OLEDs, which nearly harvest all of the generated excitons and exhibit a considerably low loss of EQE estimated from 1000 to 5000 cd m⁻². Furthermore, we reveal a new emissive approach to utilize the excitons by a combination of both TADF and exciplex emission.