The efficiency of OLEDs is fundamentally determined by the spin of excited state electrons. We have previously shown, using a new class of emissive molecules, carbene-metal-amides (CMA), an unusual emission pathway based on spin-state inter-conversion - intramolecular rotation induces a shift in the relative energies of the first excited singlet and triplet states, leading to extremely efficient singlet-triplet state interconversion and photoemission. In our recent work, we report solution-processed dual-dopant polymer LEDs, in which highly efficient electroluminescence occurs via an intermolecular energy transfer from CMAs to a fluorescent emitter. With electroluminescence from the simple fluorophore, we obtained record EQEs of >20% in these devices. Photophysical measurements indicate that ultrafast inter-fluorophore energy transfer occurs with near-unity efficiency. They preserve the relative colour purity of simple fluorophores, potential for energy-efficient printable electronics.
Quasi-two-dimensional (quasi-2D) metal halide perovskite materials possess excellent luminescent properties and suppressed trap-assisted recombination losses, having attracted much attention in the field of light-emitting diodes. Reducing the density of charge traps is essential for the further improvements of device performance. However, investigations in this direction have been limited. In this work, we study the role of some molecular additives on the suppression of trap density in quasi-2D perovskite light-emitting materials. We show that the molecular additives have a considerable effect on the reduction of hole trap density as evident in our space-charge limited current (SCLC) analysis for single-carrier devices, leading to enhanced luminescence properties. Our work contributes to the development of quasi-2D perovskite emitters for efficient LEDs.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.