Layer‐by‐Layer Deposition of Rhenium‐Containing Hyperbranched Polymers and Fabrication of Photovoltaic Cells

Abstract

Multilayer thin films were prepared by the layer‐by‐layer (LBL) deposition method using a rhenium‐containing hyperbranched polymer and poly[2‐(3‐thienyl)ethoxy‐4‐butylsulfonate] (PTEBS). The radii of gyration of the hyperbranched polymer in solutions with different salt concentrations were measured by laser light scattering. A significant decrease in molecular size was observed when sodium trifluoromethanesulfonate was used as the electrolyte. The conditions of preparing the multilayer thin films by LBL deposition were studied. The growth of the multilayer films was monitored by absorption spectroscopy and spectroscopic ellipsometry, and the surface morphologies of the resulting films were studied by atomic force microscopy. When the pH of a PTEBS solution was kept at 6 and in the presence of salt, polymer films with maximum thickness were obtained. The multilayer films were also fabricated into photovoltaic cells and their photocurrent responses were measured upon irradiation with simulated air mass (AM) 1.5 solar light. The open‐circuit voltage, short‐circuit current, fill factor, and power conversion efficiency of the devices were 1.2 V, 27.1 μ A cm−2, 0.19, and 6.1×10−3 %, respectively. The high open‐circuit voltage was attributed to the difference in the HOMO level of the PTEBS donor and the LUMO level of the hyperbranched polymer acceptor. A plot of incident photon‐to‐electron conversion efficiency versus wavelength also suggests that the PTEBS/hyperbranched polymer junction is involved in the photosensitization process, in which a maximum was observed at approximately 420 nm. The relatively high capacitance, determined from the measured photocurrent rise and decay profiles, can be attributed to the presence of large counter anions in the polymer film.

The use of sublimable chlorotricarbonyl bis(phenylimino)acenaphthene rhenium(I) complexes as photosensitizers in bulk-heterojunction photovoltaic devices

“…The applications of metal complexes and metal containing polymers for photovoltaic cells are also known [5][6][7][8][9][10][11]. Our group previously reported the use of different rhenium containing polymers for organic photovoltaic cell applications [12,13].…”

Harvesting solar energy using conjugated metallopolyyne donors containing electron-rich phenothiazine–oligothiophene moieties

“…Recently, conjugated organic polymers containing metal centers in the main chain have evolved as a new class of active materials to capture energy from the Sun [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] and this interest derives from the fact that incorporation of heavy metals into an organic conjugated framework can elicit huge effects on the electronic and optical properties of the polymers [38][39][40][41][42][43][44][45][46][47]. Among these, metallpolyynes stand out to be particularly interesting candidates in this area [23][24][25][26][27][28][29][30][31][32][33][34][35][36].…”

Main-chain metallopolymers at the static–dynamic boundary based on nickelocene

“…4,5 This diversity in structure and dynamics has facilitated a myriad of applications that include self-healing, 6,7 light emission, 8,9 photovoltaics, 10,11 stimuli-responsive behaviour, 12,13 catalysis, 14 information storage, 15 antibacterial activity, 16 and nanopatterning. [17][18][19] Main-chain polymetallocenes based on ferrocene, such as polyferrocenylsilanes (PFSs) ( Fig.…”