Hybrid systems have attracted significant attention within the scientific community due to their multifunctionality, which has resulted in increasing demands for wearable electronics, green energy, and miniaturization. Furthermore, MXenes are promising two‐dimensional materials that have been applied in various areas due to their unique properties. Herein, a flexible, transparent, and conductive electrode (FTCE) based on a multilayer hybrid MXene/Ag/MXene structure that can be applied to realize an inverted organic solar cell (OSC) with memory and learning functionalities is reported. This optimized FTCE exhibits high transmittance (84%), low sheet resistance (9.7 Ω sq−1), and reliable operation (even after 2000 bending cycles). Moreover, the OSC using this FTCE achieves a power conversion efficiency of 13.86% and sustained photovoltaic performance, even after hundreds of switching cycles. The fabricated memristive OSC (MemOSC) device also exhibits reliable resistive switching behavior at low operating voltages of 0.60 and −0.33 V (similar to biological synapses), an excellent ON/OFF ratio (103), stable endurance performance (4 × 103), and memory retention properties (104 s). Moreover, the MemOSC device can mimic synaptic functionalities on a biological time scale. Thus, MXene can potentially be used as an electrode for highly efficient OSCs with memristive functions for future intelligent solar cell modules.

The broad luminescence spectrum of a thermally activated delayed fluorescence (TADF) organic light-emitting diode (OLED) is a critical issue to overcome for its application in high-color-purity displays. Herein, a novel device structure that utilizes the first-order microcavity optical mode with a high radiance intensity is demonstrated to solve this problem by considering the charge transport properties through the analysis of hole-only and electron-only devices. In addition, by tuning the optical interference near the semitransparent top cathode layers consisting of thin silver and organic capping layers, light extraction is increased by nearly 2 times compared to the device without a capping layer. Consequently, the optimized blue TADF top-emission OLED exhibits much lower full width at half-maximum, higher maximum current efficiency, and external quantum efficiency compared to the device before optimization. This approach is expected to provide a simple but effective way to further enhance the spectral purity of the conventional TADF-based OLEDs.

A highly stretchable and transparent electrode is a key element for realizing stretchable organic light-emitting diodes (SOLEDs). To date, several reports have been made on this issue; however, a sufficiently high mechanical stability (i.e., 100% stretchability) has not yet been demonstrated. Herein, we propose a titanium particle-embedded indium zinc oxide (Ti/IZO) mesh electrode fabricated on a Norland optical adhesive (NOA) substrate for the realization of mechanically robust and efficient SOLEDs. Initially, the geometry of the Ti/IZO mesh electrode is optimized based on the simulation and experimental results, which provides a high transmittance (92.5% at 480 nm), low sheet resistance (22.1 Ω/sq), and excellent mechanical stability (no substantial loss under 100% strain; only a 20% resistance change after 1000 stretching cycles), along with a work function of approximately 5.0 eV. Next, Ti/IZO mesh-based thermally activated delayed-fluorescence blue SOLEDs fabricated on NOA substrate are transferred onto prestretched 3 M VHB tape for mechanical testing. Interestingly, the devices stably operate under 100% tensile strain and exhibit an external quantum efficiency of 13.2%, which is 30 and 29% higher than those of devices with IZO and indium tin oxide planar electrodes, respectively. The reduced waveguide mode at the interface and increased outcoupling via corrugated metal islands are attributed to the observed improvement in performance.

Flexible Memristive Organic Solar Cells In article number 2300433, Tae Geun Kim and co‐workers report a flexible organic solar cell (OSC) with memory and learning functionalities (memristive OSC) using a highly flexible, transparent, and conductive electrode based on multilayer MXene/Ag/MXene structures. The approach provides critical clues to the production of compact and intelligent future solar cell modules.

A novel device structure for thermally activated delayed fluorescence (TADF) top emission organic light-emitting diodes (TEOLEDs) that improves the viewing angle characteristics and reduces the efficiency roll-off is presented. Furthermore, we describe the design and fabrication of a cavity-suppressing electrode (CSE), Ag (12 nm)/WO3 (65 nm)/Ag (12 nm) that can be used as a transparent cathode. While the TADF-TEOLED fabricated using the CSE exhibits higher external quantum efficiency (EQE) and improved angular dependency than the device fabricated using the microcavity-based Ag electrode, it suffers from low color purity and severe efficiency roll-off. These drawbacks can be reduced by using an optimized multi-quantum well emissive layer (MQW EML). The CSE-based TADF-TEOLED with an MQW EML fabricated herein exhibits a high EQE (18.05%), high color purity (full width at half maximum ~ 59 nm), reduced efficiency roll-off (~ 46% at 1000 cd m−2), and low angular dependence. These improvements can be attributed to the synergistic effect of the CSE and MQW EML. An optimized transparent CSE improves charge injection and light outcoupling with low angular dependence, and the MQW EML effectively confines charges and excitons, thereby improving the color purity and EQE significantly. The proposed approach facilitates the optimization of multiple output characteristics of TEOLEDs for future display applications.