Enhanced Performance and Stability of Polymer BHJ Photovoltaic Devices from Dry Transfer of PEDOT:PSS

• Published in: ChemSusChem Vol. 7; no. 7; pp. 1957 - 1963
• Main Authors: Kim, Jung Kyu, Park, Insun, Kim, Wanjung, Wang, Dong Hwan, Choi, Dae-Geun, Choi, Yeong Suk, Park, Jong Hyeok
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.07.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Bridged Bicyclo Compounds, Heterocyclic - chemistry; Electric Power Supplies; electrochemistry; hole extraction layer; Photovoltaic cells; polymer solar cells; Polymers - chemistry; Polystyrenes - chemistry; power conversion efficiency; Silicon wafers; Solar Energy; stamping-transfer; Tin Compounds - chemistry; power conversion efficiency; polymer solar cells; stamping-transfer; electrochemistry; hole extraction layer
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201400022

Polymer solar cells with enhanced initial cell performances and long‐term stability were fabricated by performing a simple dry transfer of a hole extraction layer [poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)] onto an indium tin oxide (ITO) substrate. Due to the very flat surface of the polyurethane acrylate/polycarbonate (PUA/PC) film, which was used as a mold and resembled the surface of the original substrate (silicon wafer), the transferred layer had a very smooth surface morphology, resulting in enhancement of the interfacial characteristics. The work function of the PEDOT:PSS layer and the morphology of bulk hetero junction (BHJ) layer were tuned by controlling the position of PSS enrichment in the PEDOT:PSS layer using the dry transfer. The power conversion efficiency of PTB7:PC71BM BHJ device prepared by the dry transfer was 8.06 %, which was significantly higher than that of the spin‐cast device (7.32 %). By avoiding direct contact between the ITO substrate and the PEDOT:PSS solution in the dry transfer system, etching and diffusion of indium in the ITO substrate were greatly reduced, thereby improving the stability. Smoothing it over with a stamp: Bulk‐heterojunction polymer solar cells with enhanced device performances and a long‐term stability are fabricated using a simple dry transfer method. Due to the reverse poly(styrenesulfonate) (PSS)‐enriched region in the transferred poly(3,4‐ethylenedioxythiophene (PEDOT):PSS layer, its work function and morphology can be tuned. Furthermore, by avoiding direct contact between substrate and PEDOT:PSS solution, the stability is improved.