No abstract

Owing to the sensitivity of the perovskite thin film to solvent, preparation of metal top electrode by solution process is of great challenging. This is the key technology for the realization of fully solution processed perovskite solar cells. In this paper, we report the preparation of transparent silver nanowires (AgNW) top electrode for perovskite solar cells using inkjet printing process. Experiment results demonstrate that low device performance with low fill factor was obtained when the AgNW is directly printed onto the PC61BM layer. This is ascribed to the mismatched work functions of the AgNW electrode and PC61BM layer, and the solvent assisted chemical corrosion of the AgNW electrode by halogen anions. By inserting a thin layer of polyethylenimine (PEI), the charge injection barrier between PC61BM and AgNW electrode was minimized. More importantly, such a thin PEI layer suppresses the chemical corrosion of AgNW electrode during printing, yielding a condensed and uniform AgNW networks. The introduction of a thin PEI layer greatly improves the device performance and stability. A high power conversion efficiency of 14.17% with an averaged light transmittance of 21.2% was achieved for the PEI/AgNW cells. In addition, improved performance stability was measured for the PEI/AgNW cells.

In the aim to realize high performance semitransparent fully coated organic solar cells, printable electrode buffer layers and top electrodes are two important key technologies. An ideal ink for the preparation of the electrode buffer layer for printed top electrodes should have good wettability and negligible solvent corrosion to the underlying layer. This work reports a novel organic-inorganic composite of phosphomolybdic acid (PMA) and PEDOT:PSS that features excellent wettability with the active layer and printed top Ag nanowires and high resistibility to solvent corrosion. This composite buffer layer can be easily deposited on a polymer surface to form a smooth, homogeneous film via spin-coating or doctor-blade coating. Through the use of this composite anode buffer layer, fully coated semitransparent devices with doctor-blade-coated functional layers and spray-coated Ag nanowire top electrodes showed the highest power conversion efficiency (PCE) of 5.01% with an excellent average visible-light transmittance (AVT) of 50.3%, demonstrating superior overall characteristics with a comparable performance to and a much higher AVT than cells based on a thermally evaporated MoO/Ag/MoO thin film electrode (with a PCE of 5.77% and AVT of 19.5%). The current work reports the fabrication of fully coated inverted organic solar cells by combining doctor-blade coating and spray coating and, more importantly, demonstrates that a nanocomposite of a polyoxometalate and conjugated polymer could be an excellent anode buffer layer for the fully coated polymer solar cells with favorable interfacial contact, hole extraction efficiency, and high comparability with full printing.