Synthesis of conjugated polymers bearing indacenodithiophene and cyclometalated platinum(II) units and their application in organic photovoltaics

• Published in: Solar energy materials and solar cells Vol. 109; pp. 111 - 119
• Main Authors: Liao, Chuang-Yi, Chen, Chih-Ping, Chang, Ching-Chih, Hwang, Gue-Wuu, Chou, Ho-Hsiu, Cheng, Chien-Hong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2013; Elsevier
• Subjects: Applied sciences; Current density; Cyclometalated polymers; Devices; Electric potential; Energy; Exact sciences and technology; Illumination; Natural energy; Organic photovoltaics; Photovoltaic cells; Photovoltaic conversion; Platinum; Polymer blends; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Thiophenes; Organic photovoltaics; Cyclometalated polymers; Platinum; Short circuit currents; Conversion rate; Organometallic polymer; Bearing(mechanics); Amplitude modulation; Organic polymers; Thiophene; Organic solar cells; Fill factor; Open circuit voltage; Butyric acid; Ester; Conjugated polymer; Electrochemical properties; Space charge limited conduction; Diversity combining; Energy conversion; Density functional method; Illumination; Comparative study
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2012.09.033

With the goal of applying them in organic photovoltaics (OPVs), in this study we synthesized two organometallic alternating conjugated polymers, TPT–TPyPt and TPT–TIqPt, consisting of indacenodithiophene (thiophene/phenylene/thiophene; TPT) and cyclometalated platinum(II) moieties and compared their optical, electrochemical, and photovoltaic properties, their space charge limited currents, and their structures (density functional theory) with those of related platinum-free organic polymers, TPT–TPy and TPT–TIq. The absorption bands of the metal-based polymers were significantly red-shifted relative to those of the metal-free polymers. We fabricated OPVs incorporating blends of these polymers and [6,6]-phenyl-C71-butyric acid methyl ester at various weight ratios. One of these devices exhibited a power conversion efficiency (PCE) of 2.9%, with a short-circuit current density of 7.7mA/cm2, an open-circuit voltage of 0.78V, and a fill factor of 0.48, under AM 1.5G (100mW/cm2) illumination. To the best of our knowledge, this PCE is the highest reported for a PSC based on a cyclometalated platinum-type polymer. From a study of a series of Pt-containing and Pt-free polymers, an organic photovoltaic device has been developed exhibiting a power conversion efficiency of 2.9%, with a short-circuit current density of 7.7mA/cm2, an open-circuit voltage of 0.78V, and a fill factor of 0.48, under AM 1.5G (100mW/cm2) illumination. [Display omitted] ► The organometallic alternating conjugated polymers have been synthesized. ► The optical, electrochemical, SCLC, and DFT calculation of these polymers are studied in detail. ► The absorption bands of Pt-based polymers show more redshifted than those of Pt-free polymers. ► A power conversion efficiency of 2.9% is obtained by using the blend of TPT–TPyPt/PCBM.