Nanostructured morphology of P3HT:PCBM bulk heterojunction solar cells

• Published in: Solid-state electronics Vol. 54; no. 4; pp. 447 - 451
• Main Authors: Kalita, Golap, Masahiro, Matsushima, Koichi, Wakita, Umeno, Masayoshi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2010; Elsevier
• Subjects: Annealing; Applied sciences; Compound structure devices; Cross-disciplinary physics: materials science; rheology; Devices; Electronics; Energy; Exact sciences and technology; Fullerene derivative; Heterojunctions; Materials science; Morphology; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanostructured morphology; Natural energy; Optoelectronic devices; Organic solar cells; Other topics in nanoscale materials and structures; Percolation; Photovoltaic cells; Photovoltaic conversion; Physics; Poly(3-hexylthiophene); Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; 72.40.+w; 73.61.Ph; 72.80.Rj; Poly(3-hexylthiophene); Fullerene derivative; Organic solar cells; Nanostructured morphology; 73.63.Bd; Performance evaluation; Annealing; Fullerene compounds; Annealing temperature; Composite material; Solar cell; Transmission electron microscopy; Thiophene derivative polymer; Optoelectronic device; Percolation; Nanostructured materials; Nanocrystal; Heterojunction
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2009.11.010

Organic bulk heterojunction solar cells based on poly(3-hexylthiophene) (P3HT) and the fullerene derivative (PCBM) were fabricated and nanostructured morphology were investigated. Bulk heterojunction solar cells were fabricated with concentration ratio 1:0.5, 1:1 and 1:2 of P3HT and PCBM. Nanostructured morphology of P3HT:PCBM composite films were investigated with annealing temperature and variation of composition ratio, which were correlated with device performance. Fabricated solar cells annealed at 150°C show much better device performance than that of the cells without annealing. Transmission electron microscopy (TEM) study shows formation of PCBM nanocrystals in the P3HT composite film with annealing. The formations of elongated PCBM nanocrystals provide an efficient percolation path for the electron, thereby improving device performance. Better device performance was observed with 1:1 as compared to 1:0.5 and 1:2 concentration ratios of P3HT and PCBM. With decrease in PCBM content, there were no efficient percolation paths for electron; on the other hand there were poorer intermolecular packing with increased PCBM content leading to lower device performance.