Transparent Organic Light‐Emitting Diodes: Advances, Prospects, and Challenges

Transparent organic light‐emitting diodes (TOLEDs) are exciting next‐generation electronic devices that can be embedded and integrated into walls, windows, head‐up panels in commercial and domestic buildings, cars, planes, and other segments of the consumer goods sector. TOLEDs are also fundamental components for the realization of the stacked OLEDs for various industrial and research applications. Furthermore, futuristic smart wearables for clothing as well as medical purposes will also benefit remarkably from the development of TOLEDs. However, the efficiency of TOLEDs is significantly lower than that of their opaque counterparts. The achievement of high‐performance TOLEDs is directly dependent on the properties of the chosen electrode materials as well as the used light extraction techniques. In this review, the reported perspectives of TOLEDs are discussed along with their types, design, and architectures, applied TOLED materials and properties, and the application fields of these transparent devices. The performance of the electrode materials and the commonly used light extraction methods are reviewed in detail as well. The main purpose is to shed light on some of the effective TOLED approaches and the underlying reasons for the frequently encountered issues in these diodes. Auspicious novel fabrication techniques as well as device structures are also highlighted. In this review, the current state and perspectives of transparent organic light‐emitting diodes (TOLEDs) are discussed, including their types, design and architectures, materials and properties, as well as the applications of TOLEDs based on the reported progress in the field. The trade‐off between the high performance and stability of devices is also summarized.