Study Of New-type Organic Solar Cells And Film Preparation Method

Polymer solar cells (PSC) are one of the promising photovoltaic technology, dueto its advantages of flexible, portable, cheap and less environmental pollution. PSCswere prepared using two conjugated polymers as electron donor and a conjugatedpolymer as electron acceptor. The best performance was achieved with thestoichiometry of1:1. It was found that thermal annealing has a pronounced effect ondevice performance. Annealing can alter the morphology of active layer, which resultsin the increase of distance for exciton diffusion and the decrease of interface area forexciton separation, leading to the decrease of device performance. It was alsoobserved that solvent has little effect on device performance, which was differentfrom fullerene-based polymer solar cells. Moreover, it demonstrated that crystallinityof donor polymer also has a significant effect on device performance, despite ofsimilar LUMO and HOMO energy bands.Inverted PSC is more stable than the traditional one. The power conversionefficiency (PCE) was improved from0.34%to1.28%by using ZnO as the electrontransport layer. The oxygen-plasma treatment of ZnO thin film can significantlyimprove the device performance. Finally, the PCE reached1.77%when the1nmmagnesium was evaporated on the ZnO film.Blading, spraying and slot die are new solution film preparation methods, withthe low cost, fast preparation and good film quality. Most importantly, they arecompatible to the roll to roll technology, playing a vital role in the popularization andapplication of PSCs. Several film preparation machines were fabricated, with theadvantages of high speed, material saving and suitable large-area fabrication, etc..They laid a solid foundation for further research.