A detailed experimental and theoretical investigation of the role of cyano groups in the π-bridged acceptor of sensitizers for use in dye-sensitized solar cells (DSCs)

摘要: Three donor-π conjugated unit-acceptor (D-π-A) type zinc porphyrin sensitizers LX1, LX2 and LX3 bearing meso acrylic acid, α-cyanoacrylic α-cyanopentadienoic respectively, as the π-bridged acceptors were designed synthesized for use in dye-sensitized solar cells (DSCs). The interesting role of cyano group attached to α position pentadienoic acid acceptor was investigated. It shown that even though introduction elongation π-bridge can both increase light-harvesting indicated by UV-vis absorption spectra, relevant cell performance dropped significantly. photo power conversion efficiencies (PCEs) devices order LX1 > LX3, with highest PCE 6.04% achieved LX1-based cell, which bears acceptor. To further explore effect -CN -CH[double bond, length m-dash]CH- on interaction between absorbed dye TiO2 substrates, their density states (DOS) partial (PDOS), well electronic properties investigated detail using theoretical calculations. results suggest introducing into extending conjugation have decreased LUMO levels dyes, leading weak interfacial coupling, low electron injection driving force, Jsc, thus poor performance.