TITLE:
Effects of PBr3 Addition to Polysilane Thin Films on Structures and Photovoltaic Properties
AUTHORS:
Junya Nakagawa, Takeo Oku, Atsushi Suzuki, Tsuyoshi Akiyama, Masahiro Yamada, Sakiko Fukunishi, Kazufumi Kohno
KEYWORDS:
Microstructure, Thin Film, Property, Polysilane, Solar Cell
JOURNAL NAME:
Green and Sustainable Chemistry,
Vol.7 No.1,
February
10,
2017
ABSTRACT: Organic
thin film solar cells are potential next generation solar cells. Many p-type
semiconductors have been used in organic solar cells, but there have been far
fewer reports involving n-type organic semiconductors. Developing new n-type
organic semiconductors is therefore desirable. Polysilane thin films were
spin-coated from solutions containing phosphorus (P), and the effects of P
addition on film microstructures and electronic properties as n-type semiconductors
were investigated. Microstructures of poly-methyl-phenyl-silane (PMPS),
dimethyl-polysilane (DMPS) and deca-phenyl-penta-silane (DPPS) thin films were
investigated by X-ray diffraction and transmission electron microscopy. PMPS
thin films doped with P (PMPS(P)) were amorphous upon annealing at 300°C, while DMPS(P) and DPPS(P) thin films
exhibited crystalline structures. PMPS(P) and DMPS(P) thin films exhibited
decreased electrical resistances upon P doping. The energy gaps of PMPS(P),
DMPS(P) and DPPS(P) were 3.5, 3.9 and 3.8 eV, respectively. Decreased
photoluminescence intensities of PMPS, DMPS and DPPS were observed upon P
doping. The desorption of phenyl and methyl groups from PMPS(P) thin films was
observed from Raman scattering measurements. Solar cells containing polysilane(P)/poly[3-hexylthiophene]
heterojunction structures were fabricated and exhibited photovoltaic behavior.