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On the basis of thieno(3,2-<i>b</i>)thiophene and dithieno[3,2-<i>b</i>:2&#8242;,3&#8242;-<i>d</i>]thiophene (<b>T2</b> and <b>T3</b> moieties) as &#960;-linker, the <b>A</b>, <b>D</b> and <b>S</b> series dyes were designed to investigate the effect of the introducing N⁺ as an &#8220;electron trap&#8221; into <b>T2</b> and <b>T3</b> on the properties of the dyes. The optimized structures, electronic and optical properties were investigated by the density functional theory (DFT) and time-dependent DFT (TD-DFT). The results show that the properties of the dyes are sensitive to the N⁺ position in &#960;-linkers. <b>D</b> series dyes with electron-withdrawing units located near the donor have better properties than the corresponding <b>A</b> series with the electron-withdrawing units located near the acceptor. For <b>A</b> and <b>D</b> series, the N⁺ modified dye named <b>T2N+1-d</b> displays the largest red shift of the UV&#8722;vis absorption, the maximum integral values of the adsorption-wavelength curves over the visible light, the highest light harvesting efficiency (LHE, 0.996), and the strongest adsorption energy (&#8722;44.33 kcal/mol). <b>T2N+1-d</b> also has a large driving force of hole injection (&#916;<i>G</i>_inj, &#8722;0.74 eV), which results in a more efficient hole injection. Bearing a lengthier &#960;-linker than <b>T2N+1-d</b>, the properties of <b>T2N+1-s</b> are further improved. <b>T2N+1-d</b> moiety or its increased conjugated derivatives may be a promising &#960;-linker.