Synthesis of metallophthalocyanines and perylene bisimide derivatives for utilization in organic solar cells

Metallophthalocyanines (MPc) such as CuPc, ZnPc and NiPc have been studied as donor materials for organic solar cells, because they have good hole mobilities and strong absorption (∼10⁵ cm^-1) in the visible range. The change of centered metals in Pc ring will affect the electrical and optical properties of metal Pcs which may improve the performance of MPc based solar cells. Due to their strong electron affinity, electrochemical stability, and relative ease of modifying their molecular properties and purification, perylene bisimide derivatives (PTCBI) are potential candidates as acceptors for solar cells instead of C₆₀. In this presentation, different type of metallophthalocyanines and PTCBI were synthesized and characterized (Fig 1). To improve the device performance, it is important to increase the exciton diffusion length and tune the absorption range by modifying the chemical structure of PTCBIs. The hole mobility and optical properties of each material extracted from the space charge limited current model and its relationship with the molecular crystal structure and the solid state thin film will be presented as well. Different synthetic and purification methods will affect the purities of the materials, and in turn the devices performance. Using MPc's of CuPc, ZnPc, PdPc and PtPc as donor materials, and PTCBIs as an acceptor, organic solar cells are fabricated and compared. In this regard, devices using PdPc gave conversion efficiency of 2.0 % under AM1.5 illumination at 100 mW/cm².