Toward a Stretchable Organic Light‐Emitting Diode on 3D Microstructured Elastomeric Substrate and Transparent Hybrid Anode

Abstract

expected to find applications in wearable displays, [3,4] electronic skin, [5] and wearable healthcare monitoring. [6] Stretchable OLEDs can be fabricated via structural engineering [7][8][9][10] or by developing intrinsically stretchable materials. [11] Several structural engineering methods have been developed to fabricate stretchable OLEDs. For example, stretchable active-matrix OLEDs were designed in an island-bridge architecture in which "island-like" rigid OLED units were transferred on elastomeric substrates with "bridge-like" stretchable conductive materials. [9] Another approach to develop stretchable OLEDs is transfer printing of OLEDs fabricated on an ultrathin substrate to a prestretched elastomeric substrate and releasing prestrain to create a stretchable OLED with a wrinkled or wavy configuration. [7,8] Attaching OLEDs on ultrathin substrates to prestrained elastomeric substrates with long-period gratings result in stretchable OLEDs with ordered buckling, high efficiency, and good mechanical robustness. [10] High performance stretchable OLEDs have been reported based on these approaches. However, transfer processes and multiple steps are used in these approaches making fabrication complex, costly, low-yielding, and difficult to control.There has been one report on stretchable OLEDs made using intrinsically stretchable materials. [11] Meanwhile, several stretchable light-emitting devices have been demonstrated in another structure, including stretchable polymer-based light-emitting devices, [4,12] and stretchable light-emitting electrochemical cells. [13] This approach has limited the selection of materials to maintain elasticity for all constituent layers of the devices. Moreover, the fabrication of intrinsically stretchable light-emitting devices is based on solution processing of multistacked layers, which faces several problems associated with dissolution, mixing, or cracking of the underlayer. Therefore, it is still a significant challenge to directly fabricate a stretchable OLED on an elastomeric substrate by using conventional materials and fabrication processes.An indium-tin oxide (ITO) film is commonly used as a transparent anode in traditional OLEDs, and this results in several challenges in the development of stretchable OLEDs. For example, the ITO film is brittle and tends to induce cracks under mechanical deformation. [14] ITO thin films are fabricated via sputtering processes and thermal annealing at high temperature, which are incompatible with the elastomeric substrates.Stretchable organic light-emitting diodes (OLEDs) are attractive for applications in wearable displays, conformal optical biomedical devices, and healthcare monitoring. Although many stretchable OLEDs have been demonstrated, their fabrication process still faces some limitations, including fabrication complexity, high cost and low yield, as well as difficulty controlling and obtaining materials for all constituent layers. Herein, a simple approach toward a stretchable OLED is proposed by directly depositing all consti...

A stretchable ultraviolet-to-NIR broad spectral photodetector using organic–inorganic vertical multiheterojunctions

“…The fundamental characteristics and fabrication process of the 3D-MPSS have been presented previously. 26,33,34 The 3D-MPSS with bumps and valleys was designed in a hexagonal close-packed structure (Fig. S1 †), which allows it to efficiently absorb stretching strain in the lateral direction with minimal stress concentration.…”

Flexible Hybrid Sensor Systems with Feedback Functions

“…[ 321,322 ] To achieve such skin‐mounted, smart, visualized sensor systems, various displays with high pixel resolution, high sensitivity, and superior deformability have been developed, such as inorganic/organic/polymer/quantum‐dot light‐emitting diodes (LEDs), or electroluminescent/electrochromic/thermochromic/mechanoluminescent displays. [ 323–329 ] A pioneering work regarding human‐readable flexible sensors was reported by Wang et al., who integrated a pressure‐sensitive rubber (PSR) on organic LED (OLED) arrays (Figure 10b–d). [ 310 ] Upon applying pressure, the conductivity change induced by the intensity of local stress respond to the brightness of the OLED by using an active‐matrix backplane as switches, due to their advantages in minimizing signal crosstalk.…”

Stretchable Broadband Plasmonic Photodetector Based on a Hybrid and Composite of Metal Nanoparticles and Organic Semiconductor

“…Therefore, SBPPDs efficiently absorb stretching strain in the lateral direction with minimal stress concentration. [7,[24][25][26][27] The fabrication process of the SBPPDs is presented in Figure 1b. The PEDOT:PSS was directly spincoated on a PDMS substrate with a mogul structure.…”