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采用插入较厚(40,80和120nm)的BCP空穴阻挡层,制备了结构为ITO/CuPc/NPB/Alq3/BCP(xnm)/Al的有机发光二极管,并在不同温度下测量了器件电流随外加磁场的变化(即magneto-conductance,MC).发现不同厚度BCP插层器件在低场(0B50mT)下均表现为正磁电导效应,且这一特性与器件工作温度无关.但高场部分(B>50mT)的MC却表现出对温度及厚度有较强的依赖关系,即随着温度的降低,120nmBCP插层器件表现出明显的正负磁电导转变;而80和40nm的BCP器件则不存在这种转变现象,在低温下只存在负磁电导成分.其原因可能是:MC低场正磁电导部分由超精细相互作用引起;而高场MC的正负转变则主要是由于较厚BCP插层引起大量没有复合的剩余空穴,与低温下长寿命的三重态激子相互作用(即TQA作用)引起的.
Organic light-emitting diodes of the structure ITO / CuPc / NPB / Alq3 / BCP (xnm) / Al were fabricated by inserting thicker BCP hole blocking layers (40, 80 and 120 nm) and device currents were measured at different temperatures With the change of the applied magnetic field (ie, magneto-conductance, MC), it is found that the BCP intercalation devices with different thicknesses exhibit positive magneto-conductance effect in the low field (0B50mT), and this feature has nothing to do with the device operating temperature. (B> 50mT), MC showed a strong dependence on temperature and thickness, that is, as the temperature decreased, 120nmBCP intercalation devices showed significant positive and negative magnetic conductivity changes; and 80 and 40nm BCP device There is no such phenomenon and there is only negative magnetic conductance component at low temperature, which may be due to the fact that the MC low-field positive magnetic conductance is caused by hyperfine interaction, while the positive and negative transition of high-field MC is mainly due to the thicker The BCP intercalation causes a large number of unoccupied remaining holes to interact with long-lived triplet excitons (ie, TQA action) at low temperatures.