Cyclopenta-embedded Arenes With Enhanced Stability:Preparation And Photoelectric Devices

In recent years,polyacenes have been widely used as promising candidates in organic light emitting diodes（OLEDs）,organic photovoltaics（OPVs）and lasers et al due to the large conjugated structure and uniqueπ-electron del^ocalization characteristics.However,the solubility,stability and antioxidation ability are relatively poor,and design and synthesis of novel arenes has become a hot topic in recent years.One method is to embed heteroatoms into the parent acene skeleton,and the other is to implant cyclopenta ring into the arene.The electron-withdrawing ability of cyclopenta ring could reduce the HOMO energy level,and the molecular stability is enhanced.In this thesis,a series ofπ-conjugated compounds modified by cyclopenta units have been synthesized and their phtophyscial proeprties were investigated in detail.Subsequently,we fabricated the photoelectronic converters and examined the device performance.The thesis is mainly divided into the following sections:（1）Compounds 8 and 13 have been achieved via Suzuki coupling and cyclization reaction between small twistacene and pyrene boric acid,where the latter includes cyclopenta rings.Molecule 13 exhibits obvious red-shift of absorption and emission spectra compared with 8.8 emits strong cyan light and 13 emits orange light.The OLEDs were constructed with8 and 13 as emitters.The maximum external quantum efficiency（EQE）of the device based on 8 is 2.0%and the maximum lightness is 5620 cd/m²;the maximum EQE of the device based on 13 is 0.8%and the maximum lightness is 2647 cd/m².（2）In accordance with the previous synthetic strategy,the central molecule pyrene was replaced with naphthalene and anthracene.The twisted acenes were reacted with naphthalene boric acid pinacol ester and anthracene boric acid pinacol ester,respectively,followed by cyclization reaction to afford 20,21 and 24 with cyclopenta units,in which molecules 20 and24 possessed a mismatch structure.All of them emit strong red,orange,red light.Their absorption bands are wide,and they can be chosen as the donors of OPV devices.The maximum PCE reaches to 4.21%by using 20 as a donor and PC₇₁BM as an acceptor.In addition,under the oxidation of NOSbF₆,their absorption spectra are red shifted obviously and the ESR peaks appear,indicating that these molecules form free radical positive charge,and then generate the cations.This study shows that these arenes can be used as donor materials for OPV devices and as potential magnetic materials.