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

Abstract

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.

Inverted semitransparent perovskite nanocrystal light-emitting diodes with a conjugated polymer as an electron transport layer

“…7,8 In fact, apart from the application of the opaque PNC-LEDs in life, transparent light-emitting diodes (LEDs) are also necessary in many cases, such as wearable devices, vehicles and future displays. [9][10][11][12][13] Currently, most transparent display products are based on organic LEDs or special integrated LEDs, and their performances are signifi-cantly limited by their color purity and narrow color gamut. 14,15 Therefore, it is still challenging to achieve highquality and vivid pictures from them.…”

High-Efficiency Semitransparent Light-Emitting Diodes with Perovskite Nanocrystals

“…The development of artificial intelligence enables us to put forward new visions of future life, one of which is the application of transparent display products in our lives such as augmented reality/virtual reality head-mounted displays, window displays, wearable and medical devices, instrument displays, and wallpaper technologies. − Outstanding performance is essential for translucent displays such as high brightness, good transparency, and high external quantum efficiency (EQE). In addition, high color purity (narrow emission spectrum) and wide color gamut are also the pursuits for vividness both in opaque and transparent displays. − Thus, although transparent organic light-emitting diodes (OLEDs) have achieved great processes, translucent LEDs with higher color purity and wider color gamut are still worth researching to achieve a more vivid display performance. , As photoelectric materials, perovskite nanocrystals (PNCs) have attracted extensive research in recent years due to narrow tunable emission wavelength, high photoluminescence (PL) efficiency, and easy and low-cost synthesis methods and could meet the requirements of wide color gamut and high color purity .…”

P‐13.9: Simultaneously Determination of Emitting Dipole Orientation and Distribution in OLEDs by a Two‐Step Inversion Method

“…Organic light-emitting diodes (OLEDs) are devices that convert electricity into light directly, and have been successfully used in display and lighting applications [1,2] . Under the applied voltage, the electrons and holes in OLEDs overcome the surface energy barrier and pass through the functional layers, such as the electron transport layer (ETL), the hole transport layer (HTL), etc., and then recombine into dipoles in the emissive layer (EML), where photons are radiated.…”