Fabrication And Interface Optimization Of Organic Light-emitting Devices Based On Organic Semiconductor Crystals

Organic semiconductor crystals have the properties like availability in the low cost fabricating process,flexibility, high fluorescence efficiency and so on. In addition, their advantages such as highly ordered molecular arrangement,low mpurity content and carrier mobility compare with aorphous materials make them be attractive candidates for argannic light-emitting diodes(OLED),organic field-effect transistor(OFET) and optically pumped lasers.Organic semiconductor crystal using for electroluminescent devices are in 1963,however,up to now,the reports on OLEDs based on organic crystal is scarce, even though it is easy to growth organic crystal. There is a big issue in the devices fabrication.In past reports,most of them are adhere the crystal to bottom electrode by van der Waals’ force.It can lead to terrible devices performance,especially working on high current density.Here we use a simple method to improve this problem,we can evaporate a lot of layers on two side of the crystal respectively like the organic small molecule material devices.The two organic crystals are difficult to fit tightly together,so we doped he crystal material to another by Physical vapor transport method.The tetracene and pentacene doped into BSB-me together, It can detect a plurality of wide fluorescent peaks in the visible region. The white light –emitting devices may prepare by this method.Template stripping technique can solve the electrode contact problems with crystals. By this method we prepared a number of different crystal device, However, the device driving voltage is too high and performance is poor. Fluorescence emitted can detect below 5V by using Mo O3 to modified anode to reduce the hole injection barrier. To further improve the performance of the device,we use TPBi as a hole blocking layer material to balance the electron and hole mobility.