Organic Bulk Heterojunction Solar Cells

The bulk heterojunction (BHJ) organic solar cells have the potential for harnessing low-cost solar energy because of their many advantages when compared with their inorganic counterparts, such as simple device structure, low cost, abundant materials, light weight, and easy large area fabrication on flexible substrates. This chapter describes the bulk heterojunction solar cell in five parts: the basics, device structure, materials design, morphology, and interface engineering. It highlights and discusses some of the important classes of materials that have shown promise as alternative electron acceptor materials in organic solar cells. The chapter describes the basics of organic bulk heterojunction solar cells, including conventional structures, basic characterization methods, the materials of the photoactive layers, preparation techniques, etc. The BHJ solar cells possess a sandwich structure with a blend active layer containing two components, a conjugated polymer or a small molecule as the electron donor and a fullerene derivative as the electron acceptor between two electrodes.