Evolution of Organic Light Emitting Diode (OLED) Materials and their Impact on Display Technology

Organic light-emitting diodes (OLEDs) have revolutionized display and lighting technologies, offering unparalleled design, device flexibility, vibrant colors, and energy efficiency. In this comprehensive review we elucidate the evolution of OLED technology, summarizing its progression from the fundamental principles of fluorescence (1^st generation) and phosphorescence (2^nd generation) to the emergence of thermally activated delayed fluorescence (TADF) (3^rd generation), hyper fluorescence (4th generation), and exceptional future generation OLEDs. This review highlights the development and challenges of early-generation OLEDs, scrutinizing their mechanisms, emitters, and limitations. As TADF OLEDs mark a significant paradigm shift, we explore their enhanced efficiency and potential for cost-effective production without the involvement of toxic heavy metals. Building upon this foundation this review explores the burgeoning concepts of hyper-fluorescence and future-generation OLEDs, poised to push the boundaries of color purity, efficiency, and operational stability. This consolidated comprehensive exploration described herein may provide enormous information for designing future-generation OLED materials for sustainable development.