Study Of The Performance Of Inverted Solar Cell Based On ZnO Films

Organic Solar cell (OSC) has demonstrated its broad commercial applications in the future due to its thin, flexible, easy-to-low temperature and large area of non-vacuum environment devices. In recent years, an inverted structure of solar cells has become a hot research point. This type of devices usually used the ITO as the cathode, metals with high work function as the anode and the oxide semiconductor materials as the electron collecting layer, and demonstrated its dominant of stability in the air. In the choice of the electronic collection layer, Zinc oxide has always been the focus of attention. We prepared the ZnO nanostructures, and then study the performance of inverted solar cell based on ZnO flims.1. We fabricated ZnO nanoparticle film through the sol-gel method in the air, analyzed the advantages and disadvantages of the performance of nanoparticle films by SEM, XRD, and analyzed the optical character of ZnO material by Ultraviolet-Visible (UV-Vis) spectroscopy and fluorescence spectrum. Then, we used the ZnO nanoparticle film as the electron collection layer and fabricated the organic solar cell device. The structure of the device is ITO/ZnO/P3HT: PCBM/Ag. The best PCE of the device is 0.348%. We compared the devices with different anode (Ag and PH500), and drew a conclusion that the major factors to the bad electronic transmission performance were those large number of defects on the surface of ZnO nanoparticle and the interface between the particle. After the analysis of results, we find two paths to improve the performance of the ZnO hybrid solar cell. The first one is improving the electronic transmission path through the growth of ZnO nanorods; the other one is improving the performance of device by blocking layer.2. We study the preparation method and the control of the morphologies of the ZnO nanorods. We initially grasped the morphology control of ZnO nanorods by controlling the dense of seed layer and the reaction time. The length of ZnO nanorods is 100nm to 200nm, the gap is about 50nm. Then it is applied to the inverted organic solar cells. We fabricated the devices with a structure of ITO/ZnO/P3HT:PCBM/Ag, and the best performance of devices was 0.137%. Then we propose the possible ways to improve the performance of the device.3. We have successfully prepared inverted organic solar cells using ZnO nanoparticle films as the electron collecting layer. The structure of the device is ITO/ZnO/P3HT: PCBM/MoO₃/Ag. We got the best performance of device when the thickness of the MoO₃ was 2nm. The best PCE of device was 1.27%, almost 3 times than the devices without MoO₃ layer. The lifetime of the device has been markedly improved 6 times than conventional solar cells duo to the inverted structure. The result we got has building a solid foundation to improve the high performance and the air stability of device by solution process.