卒業生（SイノベGr.・夫研）の 引地達也君 (Mr. Tatsuya Hikichi) の二次元ニオブ酸カルシウムペロブスカイトナノシート電子注入層を用いた有機EL素子に関する「Two-Dimensional Ca2Nb3O10 Perovskite Nanosheets for Electron Injection Layers in Organic Light-Emitting Devices」と題する研究論文が アメリカ化学会 の ACS Applied Materials & Interfaces (IF: 8.097) に受理されました。近年、極薄電子デバイスを実現可能なグラフェンやMoS2などのナノシート材料が注目を集めています。本研究では強誘電体である Ca2Nb3O10 ナノシートを有機 EL 素子の電子注入層として応用したところ、低電圧駆動を実現できました。次世代の極薄電子デバイスのビルディングブロックの一つとして期待できます。論文中では、ナノシートの電子注入機能発現機構も含めて議論しました。
By Satoru Ohisa, Tatsuya Hikichi, Yong-Jin Pu*, Takayuki Chiba, Junji Kido,*
ACS Applied Materials & Interfaces, in press.
Abstract: We report in this article the application of calcium niobate (CNO)perovskitenanosheets for electron injection layers (EILs) in organic light-emitting devices (OLEDs).Four kinds of tetraalkylammonium hydroxides havingdifferent alkyl lengths were utilized as the exfoliation agents of a layered compound precursor HCa2Nb3O10to synthesize CNO nanosheets, including tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPAOH), and tetrabutylammonium hydroxide (TBAOH). CNO nanosheet EILs were applied in fluorescent poly(9,9-dioctylfluorene-alt-benzothiadiazole), poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT) organic light-emitting polymer-based devices. The effects of dispersion concentrations and alkyl chain length on the devices’ performances were investigated. The results demonstrated that OLEDs’ performances were related to the coverage ratio of the CNO nanosheets, their thicknesses, and their workfunction values. Among the four exfoliation agents, the device with CNOnanosheetsexfoliated by TPAOH showed the lowest driving voltage. The OLEDs with the CNO nanosheet EILs showed lower driving voltages compared with the devices with conventional EIL material lithium 8-quinolate.
