The Fabrication And Research For Organic Solar Cells Of Single And Tandem Structure

Organic solar cells with low cost, light weight, roll to roll fabrication features, have significant application in the photoelectric conversion field. To date, the power conversion efficiency (PCE) and the stability of organic solar cells are the key factors and have been focused by people. The topics of the research are about the development of new donor/acceptor materials and the fabrication of devices, which explore the relationship based on molecules structure design, devices parameters, carrier mobility and morphology. We also study the conventional and inverted construction tandem solar cells that connected by interlayer recombination. In this paper, the performances of the devices are discussed from three aspects:(1) We design, synthesize, and characterize a series of non-fullerene acceptor materials of small molecules based on bis (perylene diimide, PDIs) units and DACH bridge. The theoretical simulation shows that the introduction of the DACH bridge is facility to form the U-shape frame of PPDIs and the interaction between PDIs units. We fabricate the solar cells with inverted structure, and investigate the performance of the devices which comprise racemic and enantiomerically pure DACH-PPDIs and PTB7-Th. The morphology, carrier mobility, absorption and electric transport properties are also studied by characterizing the films and the solution. As a consequence, the highest PCE of 4.68% is achieved and different construction of the non-fullerene and various length of the carbon chains display different performance in the thesis, which provide guidance for PDI-based of non-fullerene materials.(2) We design and develop two novel copolymers, IDT-T1 and IDTT-T1, which can be used to manufacture conventional bulk hetero-junction solar cells with PC70BM. The PCEs of them are over 6% under the optimal conditions. Compare with IDT-T1, IDTT-T1 extends molecular framework, which increases its hole mobility, thus attaining higher Jsc. The conjugate polymers possess a deep highest occupied molecular orbit (HOMO) energy level, which prompt high open-circuit voltage over 0.9 V and provide conditions for tandem solar cells.(3) The nanoparticle zinc oxide (Nano-ZnO) has been synthesized and used as electron transport layer of interlayer for tandem solar cells. Using P3HT:ICBA as a bottom cell and IDTT-T1:PC7OBM as a top cell, we fabricate the tandem solar cells that connected by intermediate recombination layer (ICL). In this part, we explore different manufacturing methods of ICL for the series tandem solar cells. The results show that the composing of Nano-ZnO、PEI and PEDOT:PSS(4083) for ICL are good for hole-electron recombination of the devices. The PCEs of the tandem solar cells are better than that of single solar cells. The best PCEs of inverted tandem structure are over 7%.