Synthesis And The Photovoltaic Application Of Performance Engineered Two Dimensional Thin Films

The third key transformation of world energy from petroleum to green energy was set out by the discovery of graphene and the need to reduce pollution caused by traditional energy sources.Despite the great characteristics displayed by graphene,it has a zero bandgap thus limiting application to electronics.Further research to improve and find alternatives have thus far led to other alternatives for performance improvement.The performance improvement strategies dealt with in this thesis include formation of heterostructures and plasma surface enhancement techniques which have proven their importance in material performance enhancement.Graphene heterostructures offers possibilities of synergy in individual material characteristics to form hybrids that exhibit multiple characteristics depending on the building block components.On the other hand,doping of two dimensional materials is also an important parameter for correcting and enhancing electrical performance of devices by introduction of defective sites which act as electro catalytic active sites.These strategies have been utilised in the project as an attempt to replace the more expensive platinum?Pt?as counter electrode material.The counter electrodes?CE?prominence in dye sensitized solar cells is undisputed with research geared towards replacement of Pt with viable substitutes with exceptional conductivity and catalytic activity.This thesis reports attempts to obtain replaceable CE with better performance than of Pt based on performance improvement.This is achieved through heterostructures and doping strategies.The chemistry between the graphene oxide and ice templates leads to cellular formation of reduced graphene oxide that achieves greater conductivity to the CE in the heterostructures between graphene oxide and molybdenum disulphide?MoS₂?.The simultaneous growth of active edge oriented MoS₂ on the CE through CVD possesses high reflectivity.High reflective MoS₂ trends to increase the electro activity by absorbing more photon from the source to the dye molecules.Thus,the synergistic effect of two materials found to showcase better photovoltaic performance of 7.6%against 7.3%for traditional platinum CE.On the other hand doping strategies have proven successful in improving electro catalytic activity and conductivity of MoS₂ through nitrogen plasma implantation.Therefore,this work have provided an effective way to improve the electro catalytic activity in DSSCs.