Revolutionary organic phototransistors: light detection redefined!

Revolutionary organic phototransistors: light detection redefined!

Researchers at the Institute for Applied Physics at TU Dresden, in cooperation with the Center for Technology Development at the German Center for Astrophysics (DZA) in Görlitz and the TH Mittelhessen, have developed a groundbreaking technology. They presented a new organic phototransistor capable of efficiently detecting and storing weak light. These results were recently published in the renowned journal Nature Photonics, underlining the importance and relevance of the research. Jonas Schröder, the first author of the study, emphasizes that the new light sensors are particularly compact and do not require complex additional circuits.

The phototransistor's integrated storage mechanism opens up promising new applications, for example in multispectral imaging and cost-efficient sensor systems. Photodetectors are key components in modern technologies ranging from cameras to sensor-controlled driving systems to security systems. The research team has presented a new technology for photodetectors with the development of so-called Organic Permeable Base Transistors (OPBTs).

Innovative technology and high sensitivity

The OPBTs, which are vertical transistors made of organic semiconductors, are characterized by their energy efficiency and the ability to be thinly deposited. Dr. Johannes Benduhn, head of the OSENS group, explains that these transistors can amplify the signal through targeted charge storage. The sensitivity of the OPBTs is remarkable: they achieve responsivities of up to 10⁹A/W, which exceeds the values ​​of conventional organic photodetectors.

Another notable feature of this technology is its adaptability to different wavelengths, including UV and infrared light. In the current OPTICUS validation project, the technology is being further developed in order to increase the technological maturity and identify new fields of application. The OSENS group, which consists of experts in physics, materials science and engineering, is located at the Chair of Optoelectronics and plays a central role in this research.

Advantages over conventional technologies

The new organic photodetectors offer significant advantages over traditional silicon-based photodetectors. Thus, some of the challenges affecting conventional organic photodetectors, such as the lack of photomultiplication for the detection of ultrathin light, have been overcome in the OPBTs. Photogating in these phototransistors represents an effective method to achieve significant photo-gain.

The production of these OPBTs is done entirely by thermal evaporation, which improves their ability to be integrated into existing systems. They can also operate at low operating voltages of up to 2 V and achieve switching speeds of almost 100 MHz. These properties make them potential candidates for applications as low-light phototransistors and photo storage devices.

Organic photodetector research is a growing field in which new materials and device architectures receive ongoing attention. In addition, integration into a centimeter-sized near-infrared spectrometer has shown promising results. With continued progress in this area, the precise detection of light will play a central role in future technological developments.