As Metaverse technology (3-dimensional virtual reality world) has been rapidly developed, the importance of realizing ultrahigh-resolution microdisplays is emerging to provide users with realistic and immersive visual information. Researchers at Hanyang and Soongsil Universities reported a new material design of silicone (Si-O-Si) incorporated organic light-emitting semiconductors (SI-OLES) which can achieve over 4,000 ppi resolution by employing micro-patterning method of silicon. This study published in the journal of Nature Communications on December 12th. 

 Organic light-emitting diodes (OLEDs) have been regarded as the best candidates to implement microdisplays for Metaverse devices due to their excellent light-emitting performance, such as high color purity, instantaneous pixel response time, and low power consumption. However, since conventional OLES pattering technologies have suffered from restrictive resolution, low efficiency, or non-uniformity, a realization of well-defined high resolution OLEDs is still challenging. 

 The researchers were inspired by silicon (Si) materials capable of developing sub-micrometer pattern with reactive ion etching (RIE)-coupled photolithography (RCP) process. To impart the pattern capability of the silicon into the OLES, they developed the SI-OLES where a ladder-like silicone network is embedded into the OLES matrix. 

 The SI-OLES possessed high physico-chemical endurance like the Si materials, so that micro-pixelation of the SI-OLES could be realized by adapting the RCP process. Particularly, the researchers revealed that anisotropic etching behavior of the Si materials can be completely developed in the SI-OLES by forming silicone-based etch-blocking layer (EBL) which alleviates lateral-etch during the RIE. 

 On the basis of this, the researchers realized ultrahigh-density RGB OLES pixelation corresponding to 4,216 ppi through successive RCP processes, and finally, high-resolution full-color OLEDs was successfully demonstrated for practical usage. 

 Prof. Kim said that "This strategy presented a new material design and high-resolution pattering technique of the OLEDs by combining the high durability and anisotropic etching behavior of the Si materials with the OLES." "We expect that our approach will provide a facile route to realize hyper-realistic Metaverse devices based on ultrahigh resolution RGB OLEDoS (OLED on Silicon) microdisplay.", Prof. Kim said. 

[Reference] Kweon, H. et al. (2022) “Silicone engineered anisotropic lithography

for ultrahigh-density OLEDs” Nature Communications.

[Main Author] Prof. Do Hwan Kim (Hanyang University), Prof. Hojin Lee (Soongsil Univeristy), Mr. Hyukmin Kweon (Hanyang University), Mr. Keun-Yeong Choi (Soongsil University), Mr. Han Wool Park (Hanyang Univeristy)

* Contact :  dhkim76@hanyang.ac.kr (D.H. Kim)

   hojinl@ssu.ac.kr (H. Lee)