Intracavity metal contacts for organic microlasers
- PDF / 659,158 Bytes
- 8 Pages / 584.957 x 782.986 pts Page_size
- 30 Downloads / 183 Views
Intracavity metal contacts for organic microlasers Stefan Meister1,a), Robert Brückner1, Markas Sudzius1, Hartmut Fröb1, Karl Leo1,b) 1
Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Dresden 01187, Germany Address all correspondence to these authors. e-mail: [email protected] b) e-mail: [email protected] This paper has been selected as an Invited Feature Paper. a)
Received: 19 June 2018; accepted: 15 November 2018
The realization of an electrically driven organic solid-state laser is an ambitious but highly desirable goal. Many obstacles need to be solved before a working device can be realized. One of the most challenging tasks is an incorporation of intracavity metal contacts, which, on the one hand, would not substantially degrade optical properties of the whole device and, on the other hand, would ensure sufficient current density to reach lasing. In this paper, we present different contact compositions aiming to realize high-quality intracavity metal contacts. We build a top contact consisting of 0.5 nm of aluminum and 4 nm of silver which has a conductivity of 1.9 107 (X/m) and is not increasing the optical lasing threshold of an organic microcavity. To get a better understanding of charge carriers influencing the device performance, we have performed a set of measurements, where a hybrid OLED–MC device was excited both optically and electrically at the same time. These experiments suggest that the charge carriers do not degrade electrical performance, at least for current densities in the range of A/cm2. Moreover, our observations suggest that, in some cases, simultaneous optical excitation can contribute to more efficient electrical pumping of the OLED-MC device.
Introduction In the second half of the last century, devices based on organic materials were presented for the first time, which led to increased interest and intensified studies in this field. Such devices are organic light emitting diodes (OLED [1, 2]), solar cells [3, 4], detectors [5], transistors [6, 7], and lasers [8, 9, 10]. In particular, the first demonstration of an optically pumped polymer microcavity (MC) laser [11] caused the field of solidstate organic lasers to become a major research area. It is highly desirable to exchange optical pumping of organic solid-state MC lasers by electrical pumping to exploit all advantages offered by these systems. Nevertheless, despite intensive studies, it was not yet possible to realize an electrically driven organic solid-state laser [12] at room temperature. The main challenges for electrical pumping are related to the very high current densities [13] required to reach lasing threshold (LT). This is mostly due to strongly enhanced exciton–exciton annihilation, polaron absorption, and population of triplet states. The latter do not show fluorescence and, therefore, cannot directly contribute to the lasing process. This leads to an immense loss of pump intensity of at least 75%. Additionally,
ª Materials Research Society 2019
the relatively po
Data Loading...
