TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The device comprises a silicon substrate.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The method further comprises purifying the conjugated polymer having the functionalized end group by a process consisting essentially of precipitation and filtration. The method comprises adding a second end capping compound to the reaction mixture, where the second end capping compound comprises a second functional group selected for its ability to modulate an optical or electrical property of the conjugated polymer; and a reactive group selected for its ability to react with A or B1, so that the second functional group is coupled to an end of the conjugated polymer. Preferred Components: The functional group is selected for an ability to modulate: a charge transport property of the conjugated polymer; or a light absorption property of the conjugated polymer. The end capping compound is selected so that the functional group exhibits an electron or hole mobility of greater than 10-5 cm2/Vs. The end capping compound is selected so that the functional group exhibits light absorption coefficients larger than 104 cm-1 in visible/near infrared ray wavelength range in the solid state. The end capping compound comprises a polymer or a small molecule. The AA monomers are di-stannyl-aryl or diborane-aryl monomers, and the B1B1 monomers are di-halide, di-triflate or di-tosylate substituted monomers. The functional group is polythiophene containing end group, or a mono-brominated perylene diimide (PDI). The conjugated polymers are all-conjugated block copolymers. The monomer compound AA, the monomer compound B1B1 and the end capping compound are selected to form an all-conjugated polymer that self assembles into a phase-separated microstructure comprising donor and acceptor domains. The donor and acceptor domain exhibit a characteristic length scale of 10-20 nm. The polymerization system further comprises: a solvent in which the monomer compound AA, the monomer compound B1B1 and the end capping compound can be combined in the reaction mixture; or a reaction vessel in which the monomer compound AA, the monomer compound BB and the end capping compound can be combined. The monomer compound AA, the monomer compound B1B1 and the end capping compound are disposed together within a kit comprising many containers. EXAMPLE - No suitable example given.