Efficient Polymer Solar Cells With Fullerene Derivatives Based Interfacial Layer

Polymer solar cells (PSCs) have attracted great attentions in recent years due to their advantages of low cost fabrication, light weight and capability to be fabricated into flexible devices. At present, the research of the PSCs is focused on improvement of power conversion efficiency (PCE) and device stability for future application. The key points for increasing the PCE and stability are the design and synthesis of high efficiency photovoltaic materials and the construction of new device structures. Research is now focused on the primary between the active layer and the electrode layer, the interface modification layer and a fullerene derivative, consider the n-type semiconductor material characteristics can be used as a cathode buffer layer is desirable, and it has a high electron mobility rate, and the active layer fullerene receptors used in matching a good level, a good interface modifying material. In this paper, we design and synthesis new materials and optimize cell interface. Research and findings are summarized as follows:1-, We designed and synthesized two new derivatives of amino-modified PCBM, PCBDAN and PCBDANI as a new modification layer of the cathode, both of them synthesized from the laboratory, the processing is simple, and can be used for flexible solar batteries,also mass production is possible. Preparation of the device is simple, the modified layer is dissolved in an alcoholic solution, and without thermal annealing which facilitates the preparation of reproducibility and operability of the device. Using PCBDAN and PCBDANI as a modification layer of the cathode can be avoid oxidation and corrosion of moisture and oxygen,which greatly improve the stability of the device. From the experimental results, when used PCBDAN and PCBDANI as a modified layer of the cathode, conversion efficiency were4.16%and3.94%based on P3HT:PC60BM system, conversion efficiency were7.70%and7.69%based on PBDTTT-CT:PC70BM system,which significantly improved than that of no modified layer. This illustrates that the synthesis of fullerene derivative of PCBDANI and PCBDAN have a great value as electron transport layer material.2、We use Zracac as a new modification layer of the cathode to prepare high performance polymer solar cells.Zracac electron transport layer is a transparent layer of high performance electronic collection, which can effectively change the optical field distribution of the photovoltaic active layer and the visible light range is400-550nm.Also it can increase the absorption of visible light, can effectively increase the photocurrent, thereby increasing cell efficiency. Zracac is applicable to traditional P3HT structure and narrow-band-based material. In AMI.5G,100mW/cm2 simulated lighting conditions, the properties of the polymer solar cell that base on P3HT:PC60BM system is excellent, the photoelectric conversion efficiency is4.23%. Department of donor material narrowband PBDTBDD efficiency has reached8.77%, the highest efficiency is9.03%. Zracac is an ideal cathode modification layer which with good transparency, and soluble in alcohol solution, without thermal annealing, good stability, is an ideal alternative materials of Ca.