Advances in Flexible Organic Photodetectors: Materials and Applications

Abstract

Future electronics will need to be mechanically flexible and stretchable in order to enable the development of lightweight and conformal applications. In contrast, photodetectors, an integral component of electronic devices, remain rigid, which prevents their integration into everyday life applications. In recent years, significant efforts have been made to overcome the limitations of conventional rigid photodetectors, particularly their low mechanical deformability. One of the most promising routes toward facilitating the fabrication of flexible photodetectors is to replace conventional optoelectronic materials with nanomaterials or organic materials that are intrinsically flexible. Compared with other functional materials, organic polymers and molecules have attracted more attention for photodetection applications due to their excellent photodetection performance, cost-effective solution-fabrication capability, flexible design, and adaptable manufacturing processes. This article comprehensively discusses recent advances in flexible organic photodetectors in terms of optoelectronic, mechanical properties, and hybridization with other material classes. Furthermore, flexible organic photodetector applications in health-monitoring sensors, X-ray detection, and imager devices have been surveyed.

Remarkable Isomer Effect on the Performance of Fully Non‐Fused Non‐Fullerene Acceptors in Near‐Infrared Organic Photodetectors

“…Photodetectors (PDs) convert incoming optical signals into electrical signals and are widely used in applications such as biomedical imaging, environmental monitoring, optical communication, machine vision, etc. [1][2][3][4] The current commercial DOI: 10.1002/adom.202302210 photodetector market is dominated by devices based on inorganic semiconductors like silicon (Si) and indium gallium arsenide (InGaAs) due to their excellent charge-carrier mobility, small exciton binding energy and high stability. [5,6] Applying optoelectronic functions onto flexible and soft surfaces, especially human skin, is at the forefront of multidisciplinary research.…”

“…In particular, with the rapid development of wearable electronics, the demand for highly flexible and stretchable PDs, which can be adhered onto curved surfaces or interfaced with the human body, is continuously increasing. [6,7] However, the intrinsic features of inorganic semiconductors, such as the high brittleness and the complicated manufacturing process, make it expensive or very complex to meet this demand. [1,8] To circumvent these limitations, great effort has been put into developing novel solutionprocessable semiconductor materials, including colloidal quantum dots (QDs), [7,9,10] perovskites [11,12] and 2D materials.…”

“…[6,7] However, the intrinsic features of inorganic semiconductors, such as the high brittleness and the complicated manufacturing process, make it expensive or very complex to meet this demand. [1,8] To circumvent these limitations, great effort has been put into developing novel solutionprocessable semiconductor materials, including colloidal quantum dots (QDs), [7,9,10] perovskites [11,12] and 2D materials. [13,14] These materials have demonstrated excellent mechanical flexibility, solution processability, chemical versatility and promising optoelectronic properties.…”

Interface-Engineered Organic Near-Infrared Photodetector for Imaging Applications

“…The two key performance parameters of fast photo detectors are the optical response time (typically measured in terms of rise and fall times) and responsivity ( R ). The response time of organic photodetectors is usually slow because of the low carrier mobility of organic semiconductors (both in the organic absorber and in transport layers) in the OPD stack. , One way to improve the response time is by using inorganic semiconductors with higher mobility (>1 cm 2 /Vs) for the transport layers (both for electrons and holes). − Recent reports on high-speed photodetectors suggest that combining organic bulk heterojunction (BHJ) and organic–inorganic hybrid perovskite (OIHP) can be another way to improve the optical response time, however with an increased dark current compared to pure OPDs. , Therefore, devices with both low dark current (<1 nA/cm 2 ) and fast response time (<1 μs) are yet to be achieved.…”

Flexible and Self-Powered Solar-Blind UV Photodetector Based on the Ti/α-Ga2O3/Electrolyte Heterojunction with High Stability

“…At the same time, flexible electronics is an emerging field that can be applied to the development and production of electronic devices such as medical electronics, wearable photodetectors, storage devices, smart screens, and sensors. Flexible detectors can adapt to different substrates and have the advantages of low manufacturing cost, flexibility, lightness, portability, integration, and versatility, which can bring a lot of new functions to some practical applications. − However, the crystallization temperature required to form high-quality α-phase Ga 2 O 3 films exceeds the heat resistance of most flexible materials, or a more complex method is needed to grow Ga 2 O 3 films on flexible substrates. For example, Ding et al prepared flexible gallium oxide thin films with a responsivity of about 1.3 A/W by using a more complex inkjet printing process .…”