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Yen-Ju Cheng, U-Ser Jeng, grazing incidence small- and wide-angle X-ray scattering, Advanced Energy Materials, organic solar cell
The Collaborative Research of NSRRC User Yen-Ju Cheng and Researcher U-Ser Jeng Highlighted as a Cover of Advanced Energy Materials
The collaborative research team led by NSRRC user Prof. Yen-Ju Cheng (Department of Applied Chemistry of National Yang Ming Chiao Tung University) and Dr. U-Ser Jeng (NSRRC) conducted research on highly efficient organic solar cell. The team explored that the use of a novel non-volatile additive in the highly efficient organic solar cell (OSC) could improve power conversion efficiency (PCE) and thermal stability. The research results were published in the high-profile journal, Advanced Energy Materials, and were selected as the inside cover of the No. 12 issue.
The fullerene-based OSCs have suffered from stagnant PCE around 10-11%, and the volatile additives often leave thermally vulnerable defected pore structures in the films. Recent studies tended to focus on non-fullerene acceptor because of their remarkable synergistic effects in pushing PCE to 16-17%, but the morphological stability of the active layers of the Y6-based acceptor device awaits further optimization. The team demonstrated that the non-volatile additive, fluorinated bis(perfluorophenyl)pimelate (BF7), could effectively improve both the efficiency and thermal stability of an OSC, comprising fluorinated Y6 as the small-molecule acceptor and PM6 as the polymer donor. The PM6:Y6:BF7 device achieves an elevated PCE of 17.01%, and moreover, the BF7-elevated PCE can sustain 95% of the best PCE over 100 °C annealing for 72 hours. The team used grazing incidence small- and wide-angle X-ray scattering and differential scanning calorimetry at TLS 23A1 to observe and analyze the structural evolution of the device film, without and with BF7. A structural model is proposed according to the nano and crystal structural features observed; from which, a general guideline is proposed for the development of similar materials in the green energy technology.