Pentacene Thin Film Growth On Alkane Modified Single Crystal Substrates

Organic thin film electronic devices with the advantages of lost cost,large scale production,light,flexible,green resources,no pollution and so on,take on many market share.Compared with inorganic electronic devices,organic thin film electronic devices are not good at life time,steady work,manufacture.So many researchers work on influence factors which are related to organic thin film electronic device performances.Surely,organic thin film is key component of organic thin film electronic devices,more and more scientist pay important attention on it.Various researches show that large scale,continuous,highly ordered organic thin film with free defects has directly improved performances of organic thin film device.It is not hard to get high quality organic thin film through proper situations.However,it is necessary to find mechanism of growth behavior,chemical and physical properties.The researches about ordered distribution of molecules in coalesced domains of organic thin film and ordered distribution of molecules in domains organic thin films not only are good at development and expansion of organic thin films theory,but also it lays good foundation of low cost,high quality organic thin film device.For common thin film in device,the plane of molecule stand on substrate and adapt spectrum analysis to get the molecular structure which represents structure information of amount of molecules.But using spectrum analysis method is hard to realize the precise measure of molecular distribution of molecules in domains and domain boundary.However,scanning tunneling microscope(STM),which is popular in scientific area since 1982,can help realize the precise measure of molecular distribution.Importantly,it must work on conductive sample which planes of molecules are parallel to substrate,but common organic thin film grows on insulation substrate.In order to solve this differences between STM measure and organic thin film,it is necessary to acquire organic films on inorganic single crystal substrate.Here,we modulated the growth of uniform organic semiconductor thin films on highly oriented pyrolytic graphite(HOPG)and Au(111)by modifying its surface with solution deposited n-dotriacontane(C32H66)self-assembled monolayer.So this research play important role on growth mechanism of organic semiconductor.1.Pentacene on single crystal substratesPentacene growing on HOPG and Au(111)surfaces appear different growth behaviors.Pentacene have thin film structure on HOPG at initial stage,which molecular plane is parallel to substrate,and process needle structure which molecular plane is vertical to substrate in later period.Pentacene growing on Au(111)have dot-like structure.Pentacene on both substrates never appear thin film structure like pentacene films in devices.2.n-Alkane self-assembled thin film on single crystal substratesNormal alkanes form the self-assembled thin film on HOPG surfaces and Au(111)surfaces by solution and depositon.Alkane self-assembled thin films have the same structure on HOPG.Differently,normal alkanes form the self-assembled thin film structure on Au(111)which have important relation to carbon number.It mainly shows that the structure of dotriacontane self-assembled thin film is different from tritriacontane self-assembled thin film.All above have been said,alkane self-assembled thin film structure have more and more important relation to substrate and carbon even-odd numbers.Besides,we also find that dotriacontane self-assembled thin film have different quality by solution and deposition.We find the film adopt island-like structure.On the contrary,alkane made by solution also form high quality and large scale self-assembled thin film.These uniform films can easily induce the high quality growth of the other molecule and bring convenience to research growth theory of thin films in devices.3.Organic semiconductor thin films on(HOPG)and Au(111)by modifying n-dotriacontane(C32H66)self-assembled monolayersIn this study,we adopted multiple measure methods,which are STM,AFM and modulated the growth of uniform organic semiconductor thin films on highly oriented pyrolytic graphite(HOPG)and Au(111)by modifying its surface with solution deposited n-dotriacontane(C32H66)self-assembled monolayers.Compared with organic thin films on SiO2,these organic thin films with large scale are uniform,highly ordered,large domains and their lattice parameters are the same as organic thin films on SiO2 Besides,we required high resolution images of pentacene thin film on modified Au(111)surface by STM.These images show that molecules in pentacene thin film have highly ordered herring-bone structure.So we realized the important precise measurement of organic thin film in devices.Importantly,people can get more and more structure information and electronic properties about all kinds of organic molecules by above method.The way makes a convenience for researching the growth theory of organic thin film in devices.