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The synthesis, characterization, and photophysics of a series of solution-processable and strongly visible-light absorbing platinum(II) polyynes containing bithiazole-oligo(thienyl) rings were presented. Tuning the polymer solar cell efficiency, as well as optical and charge transport properties, in soluble, low-band gap PtII-based conjugated poly(heteroaryleneethynylene)s using the number of oligothienyl rings is described. These materials are highly soluble in polar organic solvents due to the presence of solubilizing bithiazole moieties and show strong absorptions in the solar spectra, rendering them excellent candidates for bulk heterojunction polymer solar cells. Their photovoltaic responses and power conversion efficiencies (PCEs) depend to a large extent on the number of thienyl rings along the main chain, and some of them can be used to fabricate highly efficient solar cells with PCEs of up to 2.7% and a peak external quantum efficiency to 83% under AM1.5 simulated solar illumination, which is comparable to that of poly(3-hexylthiophene)-based devices fabricated without additional processing (annealing or TiO(x) layer). The influence of the number of thienyl rings and the metal group on the performance parameters and optimization of solar cell efficiency was evaluated and discussed in detail. At the same blend ratio of 1:4, the light-harvesting ability and PCE increase sharply as the thienyl chain length increases. The present work provides an attractive approach to developing conjugated metallopolymers offering broad solar absorptions and tunable solar cell efficiency and demonstrates the potential of metalated conjugated polymers for efficient power generation.

Fundamental factors governing the ion-desorption efficiency and extent of internal-energy transfer to a chemical thermometer, benzylpyridinium ion ([BP] + ), generated in the surface-assisted laser desorption/ionization (SALDI) process, were systematically investigated using noble metal nanoparticles (NPs), including AuNPs, AgNPs, PdNPs, and PtNPs, as substrates, with an average particle size of 1.7−3.1 nm in diameter. In the correlation of ion-desorption efficiency and internal-energy transfer with physicochemical properties of the NPs, laser-induced heating of the NPs, which are dependent on their photoabsorption efficiencies, was found to be a key factor in governing the ion-desorption efficiency and the extent of internal-energy transfer. This suggested that the thermal-driven desorption played a significant role in the ion-desorption process. In addition, a stronger binding affinity of [BP] + to the surface of the NPs could hinder its desorption from the NPs, and this could be another factor in determining the ion-desorption efficiency. Moreover, metal NPs with lower melting points could also facilitate the ion-desorption process via the phase-transition process, which could lower the activation barrier (ΔG # ) of the iondesorption process by increasing the entropic change (ΔS # ). The study reveals that high photoabsorption efficiency, weak binding interaction with analyte molecule, and low melting point could be critical for the design of SALDI substrates with efficient ion desorption. ■ INTRODUCTIONSurface-assisted laser desorption/ionization (SALDI), a major branch of laser desorption/ionization (LDI) techniques, has been widely applied to mass spectrometry (MS) analysis of small molecules, and has become increasingly popular for analysis of environmental samples, forensic samples, drugs, metabolomics, and proteomics, and for imaging mass spectrometric analysis. 1−7 A key to its success is the adoption of effective substrates for the efficient absorption and controllable transfer of laser energy, which enables the efficient desorption/ionization of analyte molecules, without inducing extensive fragmentation and without introducing serious interfering background ions. Although SALDI-MS using carbon particles as the substrate was first developed in 1995, 8 the technique became popular after the introduction of nanostructured porous silicon surface as the substrate to attain a high LDI efficiency at low laser fluence. 9−11 Since then, different types and forms of inorganic-based nanomaterials, including silicon-based, 12−15 carbon-based, 1,8,16−21 and metalbased nanomaterials, 22−31 have been developed as SALDI substrates, though their analytical performances are varied and are highly dependent on their sizes, shapes, and surface properties.Fundamental study of the LDI process remains a challenging issue. While matrix-assisted laser desorption/ionization (MALDI), using organic acids as a matrix, has been developed since the 1980s, it took about two decades for its mechanism to become better studied and unde...