Highly Efficient Non-doped Blue Light-Emitting Diodes Based on Boron-Containing Carbazoles Derivatives

• Main Authors: Ming-Yu Yen, 顏銘佑
• Other Authors: 鄭如忠
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/90201898189223275942

碩士 === 國立中興大學 === 化學工程學系所 === 96 === Four dimesitylboranes-containing carbazoles (CzB, CzPhB, CzThB, CzSB) with different π-conjugated bridges were synthesized. The intermediates with different π-conjugated bridges were prepared by Stille and Horner-Emmons reaction. Finally, the target compounds were synthesized with high yields by treating compounds (CzBr, CzPhBr, CzThBr, CzSBr) with n-butyllithium (n-BuLi) and subsequently with dimesitylboron fluoride. The characteristics of four derivateives were investigated. Glass transition temperatures of four blue emitters were observed around 81~102℃. Thermal degradation temperatures were observed around 295~360℃. Photoluminescence of four emitters appeared around 403~503 nm in the thin film state. Moreover, the solid state quantum yields (Φfs) of CzThB (51 %) and CzPhB (54 %) are relatively high when compared with many blue fluorophores reported in literature. In addition, CzThB device exhibits much better electroluminescence (EL) as compared with CzPhB devices. Blue EL of Device C (ITO/NPB/CzThB/TPBI/Al) reaches a maximum EL of 28300 cd m−2 with a narrow FWHM (full-width-at-half-maximum) of 56 nm at 14 V, maximum current efficiency of 10.1 cd A−1, maximum external quantum efficiency of 6.9%, and blue CIE coordinate of (0.13, 0.21).