Narrow Bandwidth Top-Emitting OLEDs Designed for Rhodamine 6G Excitation in Biological Sensing Applications

Abstract

Organic light emitting diodes (OLED) are promising candidates offering in optical sensor applications to detect different gas compositions and excitable optical marker groups in chemical and biological processes. They enable attractive solutions for monitoring the gas phase composition of e.g., dissolved molecular oxygen (O2) species in bio reactors or excitation of fluorescent markers. In this work, we investigate different OLED devices for biomedical applications to excite the fluorescent dye rhodamine 6G (R6G). The OLED devices are built in top emission geometry comprising a distributed Bragg reflector (DBR) acting as optical mirror. The OLED is optimized to provide a very narrow emission characteristic to excite the R6G at 530 nm wavelength and enabling the possibility to minimize the optical crosstalk between the OLED electroluminescence and the fluorescence of R6G. The DBR includes a thin film encapsulation and enables the narrowing of the spectral emission band depending on the number of DBR pairs. The comparison between optical simulation data and experimental results exhibits good agreement and proves process stability. OPEN ACCESSElectronics 2015, 4 983

77‐1: Invited Paper: Ultra‐low Power OLED Microdisplay for Extended Battery Life in NTE Displays

“…In addition to display applications, OLED microdisplays may also be attractive in the field of bio-sensing, where the OLED light can be used to excite luminescent chromophores such as the renown marker molecule rhodamine 6G at 530 nm. [1] Therefore, we present our recent results on our efforts to design a highly efficient green OLED stack with narrow band width, i.e. with the main emission between 510 -550 nm.…”

“…Whereas the former is able to emit narrowly, it is less efficient than the latter, which in contrast emits in a much broader spectrum. Although such spectra can be made narrower by proper distributed Bragg reflection (DBR) filter design on top of the OLED, [1] it requires additional deposition steps. Therefore, we alternatively developed the following OLED stack architecture by varying several parameters such as layer materials, layer composition and thickness within the stack.…”

“…The key parameters can be found in the following table. (1) 25 fps 50 fps Brightness (2) 500 cd/m² I/O voltage 1.6V … 5.5V Core voltage 1.8V ±10% Temperature range -20°C … + 65°C Additional OLED voltage (2) -5V…”

Narrowband Organic Light‐Emitting Diodes for Fluorescence Microscopy and Calcium Imaging

“…Due to the small Stokes shift of eGFP, this spectral de-coupling is particularly challenging. [27] Several strategies have been suggested to make inorganic LEDs [39] and OLEDs [30][31][32]40,41] compatible with the requirements for fluorescence imaging, including the use of microcavities, DBRs, polarizers, and layers of absorbing molecules. We decided to use DBRs for our work because they offer steep spectral cut-off, high rejection in their stop band and high transmission in their pass band.…”

Exploiting the Potential of OLED-Based Photo-Organic Sensors for Biotechnological Applications

“…A ring-shaped OPD setup for filterless distinction between excitation light and the PL-response signal has been subsequently developed in a system where OLED emission is used to excite integrated sensor spots that are sensitive to ammonia, carbon dioxide, oxygen, and temperature [41]. In an alternative, recently described strategy from our groups for controlling the light emission of OLEDs used in a R6G PL-sensor, dielectric layers, so-called distributed Bragg reflectors (DBRs), are used in narrow-bandwidth top-emitting OLEDs [42]. These DBRs are placed in front of the semi-transparent cathode.…”