Efficient Inverted Solar Cells Using Benzotriazole-Based Small Molecule and Polymers

• Published in: Polymers Vol. 13; no. 3; p. 393
• Main Authors: Lee, Ja Eun, Kim, Yoon, Na, Yang Ho, Baek, Nam Seob, Jung, Jae Woong, Choi, Yura, Cho, Namchul, Kim, Tae-Dong
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27.01.2021; MDPI
• Subjects: Benzotriazole; Carbazoles; Chemical synthesis; Energy conversion efficiency; Energy transfer; Molecular structure; Molybdenum oxides; Molybdenum trioxide; Morphology; Optical properties; Photovoltaic cells; Polymers; Sensors; Solar cells; Spectrum analysis; Zinc oxide; small-molecule solar cells; polymer solar cells; morphology; molecular aggregation; benzotriazole
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym13030393

We synthesized medium-band-gap donor-acceptor (D-A) -type conjugated polymers (PBTZCZ-L and PBTZCZ-H) consisting of a benzotriazole building block as an acceptor and a carbazole unit as a donor. In comparison with the polymers, a small conjugated molecule (BTZCZ-2) was developed, and its structural, thermal, optical, and photovoltaic properties were investigated. The power conversion efficiency (PCE) of the BTZCZ-2-based solar cell devices was less than 0.5%, considerably lower than those of polymer-based devices with conventional device structures. However, inverted solar cell devices configured with glass/ITO/ZnO:PEIE/BTZCZ-2:PC BM/MoO /Ag showed a tremendously improved efficiency (PCE: 5.05%, : 9.95 mA/cm , : 0.89 V, and FF: 57.0%). We believe that this is attributed to high energy transfer and excellent film morphologies.