| 초록 |
Simple small molecular electrolytes (C4-OH and C6-OH) were designed to modify cathode interface, which enhanced an efficiency of the inverted polymer solar cells (iPSCs). Short circuit current density (JSC) and power conversion efficiency (PCE) of the devices based on new electrolytes were increased. This improvement is caused by the quaternary ammonium bromide and hydroxyl groups in C4-OH and C6-OH. These materials can form favorable interfacial dipole at the cathode interface. Thus, the work function of ITO/C4-OH (or C6-OH) is reduced from -5.0 eV to -4.58 (or -4.62) eV and ZnO/C4-OH (or C6-OH) is also decreased from -4.5 eV to -4.27 (or -4.37) eV. Higher PCEs of 9.35 % and 9.21 % than those of pristine ZnO (8.74 %) were obtained with the device based on ZnO/C4-OH (or C6-OH). Furthermore, the PCEs of devices based on electrolytes without ZnO are almost same as the PCE of the device with pristine ZnO. As a result, OSCs with two small molecules showed improved photovoltaic properties. |
