Recent advances in the molecular designs of near ultraviolet emitters for efficient organic light emitting diodes

Abstract

The exploration of pure organic violet emitters (λ_em < 420 nm) has garnered significant attention within the scientific community due to their widespread applications in various research domains, including organic light-emitting diodes (OLEDs), biomedical applications, and photolithography, etc. Despite the availability of several near-ultraviolet (NUV) sources, organic emitters have stood out due to their cost-effectiveness, flexibility, and extensive potential for functional tunability. However, the development of highly efficient NUV emitters for OLEDs faces substantial challenges and lags behind their red, green and blue counterparts, primarily due to stringent molecular requirements. Over the past decade, substantial efforts have been dedicated to devising new molecular designs aimed at striking a balance between conjugation length, donor-acceptor interactions, photoluminescence quantum yield, charge transporting properties, and color purity of violet emitters. However, a limited number of reviews were reported on different design strategies for producing violet (< 420 nm) emitters to date. Addressing this gap, this review provides an overview of recent design advances in constructing violet emitters. It delves into their structure-function relationship focusing on photophysical properties and OLED performance. Further, the current status and future prospectus of violet organic emitters are presented.