PVK三线态激基复合物的发光及其受紫外光辐照的影响

用不同溶剂中的前驱物旋涂成PVK层,制备了ITO/PEDOT:PSS/PVK/Ca:Al器件,以及相同结构不同PVK分子量的器件。通过测试分析认为:器件的电致发光谱中590nm波长处的发光峰来自于PVK三线态的激基复合物,并且发现其强度依赖于PVK的分子构型,即在PVK分子中相邻咔唑基团重叠程度。通过比较不同紫外辐照剂量后的PVK器件的发光,发现适度的UV辐照后的PVK分子构型中相邻咔唑基团处于全重叠的状态增加,在电致发光时会形成更多的三线态激子,因而提高了PLED器件的发光效率。

Emission of Electroplex in PVK and Its Properties under UV Irradiation

Polymer light-emitting devices(PLED) with the structure as ITO/PEDOT ∶ PSS/PVK/Ca ∶ Al were fabricated by spincoating PVK precursor dissolved in different solvent as emitting layer. Meanwhile, those with same structure and varied PVK molecular weight were prepared. In experiment, the peak at 590 nm was found in EL spectra and was assigned to triplet excimer in PVK layer. The intensity of the peak is depend on molecular configuration of PVK, that is on what extent the adjacent carbazole groups overlap in PVK molecule. It was found that the number of the state, that adjacent carbazole groups are completely overlapped increases in PVK molecula after proper UV irradiating. Under this condition, more triplet excitons could are generated and luminance efficiency is improved.