High current gain organic upconversion device using sublimated chloroaluminum phthalocyanine as a charge generation layer

In this work, an efficient organic upconversion device (OUD) employing the bilayer charge generation layer (CGL) of chloroaluminum phthalocyanine (ClAlPc) and C70 was demonstrated. As a result, the current gain ratio of OUD with the sublimated ClAlPc was improved from 1 000 to 40 000 as compared the non-sublimated ones. This is because the mechanism of impurity-induced at the interface of CGL/ITO was mainly dominated the total amount of dark current density in our proposed OUD. Thus, the CGL with poor blocking efficiency might result in an increase in the hole carriers into the device.