High-efficiency blue fluorescent OLEDs enabled by a cost-effective blade-coated planar source evaporation strategy

Abstract

Nowadays, vacuum thermal evaporation (VTE) has been widely applied in industrial fabrication of organic light-emitting diodes (OLEDs), though suffering from low material utilization and prolonged deposition times, which increase production cost. To address these issues, we have developed an innovative, cost-effective manufacturing system that combines blade-coating and planar source evaporation (BCPSE). In this system, donor films are fabricated via blade-coating method, achieving over 90 % material utilization and precise control over film thickness and uniformity. The resulting blue fluorescent OLEDs fabricated using BCPSE that exhibit high performance (CE = 11.1 cd/A, T₇₅ = 68,660 h at 100 cd/m²), comparable to VTE-based devices (CE = 10.6 cd/A, T₇₅ = 57,690 h at 100 cd/m²). The underlying mechanism reveals that the close-space planar source evaporation (PSE) technique effectively reduces residual impurities in the thin film, improves interfacial compatibility and promotes balanced carrier recombination, thereby enhancing both the performance and operational stability of OLED devices. This study demonstrates the practical feasibility of BCPSE technology, offering a promising approach for reducing production costs and enhancing the optoelectronic performance and stability of OLEDs in industrial-scale manufacturing.