A comparative investigation of electron transport properties in Li2CO3 doped and undoped organic semiconductors by admittance spectroscopy

Abstract

Abstract The electron transport characteristics in organic small-molecule semiconductors BmPyPB and TmPyPB doped and undoped by Lithium carbonate (Li2CO3) have been investigated by admittance spectroscopy measurements. It is found that the electron mobilities of doped films greatly improved that of undoped films. The electron mobilities of Li2CO3-doped films reach the orders of 10−4∼10−3 cm2V−1s−1, which is one or two orders of magnitude higher than that of undoped films (∼10−5 cm2V−1s−1). The electron mobility variation with electric field in TmPyPB: Li2CO3 is the same as that in BmPyPB: Li2CO3. It can be seen that the electron mobilities slightly decrease as the electric field increases. The electron transport mechanisms in the doped and undoped films have been further studied through atomic force microscopy. The performances of electroluminescent devices with correlating electron transport layers has also been investigated.