High open-circuit voltage bulk-heterojunction solar cells by using new dendritic acceptor material

T. Alshahrani, A EL-Betany, M. Mabrook, H. Tai, N.B. McKeown
Bangor University, UK

Keywords: solar cell

Summary:

Light harvesting solar cells and energy transfer are currently of great challenges for the 21st century in the field of solar cells energy. Academic and industrial scientists are searching for a detailed understanding of light harvesting and find tools to control the electron transfer between donor and acceptor molecules. Due to their electronic properties and the ability to tune their absorption ranges, conjugated dendrimers combined with polymers are used extensively in the formation of the active layer (donor- acceptor) in organic photovoltaic [1]. Dendrimers and hyperbranched polymers are considered to be the leading materials used in the application of organic solar cells. They are low viscosity with high molecular weights, good solubility and mutifunctionality. Dendrimers are perfect monodisperse macromelcular (tree-like structures) with high branched three-dimensional structures: core, branches, and end groups [1, 2]. Organic bulk-heterojunction structure (OBHJ) consist of donor and acceptor (active layer) blend together deposited between two electrodes in order to gain a large interface area between donor and acceptor [3]. However, charge mobility through the OBHJ active layer strongly depends on the morphology of surface of the active layer. thus, dendrimers materials with their small size and monodisperse nature leads to a high degree of ordering in organic solar cell devices and thus high carrier mobilities [2, 3]. Many reports indicate derivatives of 1,8-naphthalimide based on PAMAM dendron have highly efficient as an acceptor in light harvesting dendrimers [4, 5] while the Poly (3- hexylthiophene) (P3HT) possess brilliant efficiency as donor material due to its low band-gap in photovoltaic applications.