We compare the performance of luminescent solar concentrators ͑LSCs͒ fabricated with polymers and quantum dots to the behavior of laser dye LSCs. Previous research, centered around the use of small molecule laser dyes, was hindered by the lack of materials with small absorption/emission band overlap and longer lifetime. Materials such as semiconducting polymers and quantum dots present qualities that are desirable in LSCs, for example, smaller absorption/emission band overlap, tunable absorption, and longer lifetimes. In this study, the efficiency of LSCs consisting of liquid solutions of semiconducting polymers encased in glass was measured and compared to the efficiency of LSCs based on small molecule dyes and on quantum dots. Factors affecting the optical efficiency of the system such as the luminescing properties of the organic materials were examined. The experimental results were compared to Monte Carlo simulations. Our results suggest that commercially available quantum dots cannot serve as viable LSC dyes because of their large absorption/emission band overlaps and relatively low quantum yields. Materials such as Red F demonstrate that semiconducting polymers with high quantum yield and small absorption/emission band overlap are good candidates for LSCs.

Studies of materials for source-drain electrodes in ink-jet printed polymer-based thin film transistors (TFTs) are reported. Two systems are studied: a blend of Ag nanoparticles with poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and an ethylene glycol-doped PEDOT:PSS solution (modified-PEDOT). The semiconductor used is the polythiophene derivative poly [5,5′-bis(3-dodecyl-2-thienyl)-2,2,2′-bithiophene]. PEDOT:Ag blends and modified-PEDOT yield TFTs with mobilities around 10−2 and 10−3cm2∕Vs, respectively, subthreshold slopes around 1.6V/decade and on-to-off current ratios of 106–107. Both systems show considerable improvement over printed TFTs with Ag nanoparticle source-drain electrodes. Results on film resistivity and morphology are discussed along with device characteristic analysis.