Large‐area, ultrathin light‐emitting devices currently inspire architects and interior and automotive designers all over the world. Light‐emitting electrochemical cells (LECs) and quantum dot light‐emitting diodes (QD‐LEDs) belong to the most promising next‐generation device concepts for future flexible and large‐area lighting technologies. Both concepts incorporate solution‐based fabrication techniques, which makes them attractive for low cost applications based on, for example, roll‐to‐roll fabrication or inkjet printing. However, both concepts have unique benefits that justify their appeal. LECs comprise ionic species in the active layer, which leads to the omission of additional organic charge injection and transport layers and reactive cathode materials, thus LECs impress with their simple device architecture. QD‐LEDs impress with purity and opulence of available colors: colloidal quantum dots (QDs) are semiconducting nanocrystals that show high yield light emission, which can be easily tuned over the whole visible spectrum by material composition and size. Emerging technologies that unite the potential of both concepts (LEC and QD‐LED) are covered, either by extending a typical LEC architecture with additional QDs, or by replacing the entire organic LEC emitter with QDs or perovskite nanocrystals, still keeping the easy LEC setup featured by the incorporation of mobile ions.

Light‐emitting electrochemical cells (LECs) are solution processable solid‐state light sources comprising in their simplest architecture an ionic emissive layer in between of two electrodes. Although LECs possess several advantages that make them promising candidates for future large‐area low‐cost lighting technologies, their device wall‐plug efficacies remain so far moderate on the order of a few lumens per watt. One of the reasons therefore is considered to be the charge imbalance within the device. Here, a hybrid LEC device concept is introduced, whereby an additional layer of zinc oxide (ZnO) nanoparticles at the cathode side supports electron injection into the active light‐emitting layer and boosts the performance of the Ir‐based ionic transition metal complex LEC (iTMC‐LEC). The brightness and efficacy of the devices can be increased in average by more than 70% by the implementation of the additional inorganic layer. The time to reach the maximum brightness can be reduced in average by a factor of 7, which is attributed to an improved electron/hole balance in the device due to enhanced electron injection into the active iTMC layer.

The simple device architecture as well as the solution-based processing makes light-emitting electrochemical cells (LECs) a promising device concept for large-area flexible lighting solutions. The lack of deep-blue emitters, which are, at the same time, efficient, bright, and long-term stable, complementary to the wide variety of yellow-orangeemitting LECs, hampers the creation of white LECs. We present a hybrid device concept for the realization of white light emission by combining blue colloidal quantum dots (QDs) and an Ir-based ionic transition-metal complex (iTMC) LEC in a new type of white QD−LEC hybrid device (QLEC). By careful arrangement of the active layers, we yield light emission from both the blue QDs and the yellow iTMC emitter already at voltages below 3 V. The QLEC devices show homogeneous white light emission with high color rendering index (up to 80), luminance levels above 850 cd m −2 , and a maximum external quantum efficiency greater than 0.2%.

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The need for more efficient health services and the trend of a healthy lifestyle pushes the development of smart textiles. Since textiles have always been an object of everyday life, smart textiles promise, and extensive user acceptance. Thereby, the manufacture of electrical components based on textile materials is of great interest for applications as biosensors. Organic electrochemical transistors (OECTs) are often used as biosensors for the detection of saline content, adrenaline, glucose, etc., in diverse body fluids. Textile-based OECTs are mostly prepared by combining a liquid electrolyte solution with two separate electro-active yarns that must be precisely arranged in a textile structure. Herein, on the other hand, a biosensor based on a textile single-component organic electrochemical transistor with a hardened electrolyte was developed by common textile technologies such as impregnation and laminating. Its working principle was demonstrated by showing that the herein-produced transistor functions similarly to a switch or an amplifier and that it is able to detect ionic analytes of a saline solution. These findings support the idea of using this new device layout of textile-based OECTs as biosensors in near-body applications, though future work must be carried out to ensure reproducibility and selectivity, and to achieve an increased level of textile integration.