Colorful semitransparent polymer solar cells employing a bottom periodic one-dimensional photonic crystal and a top conductive PEDOT:PSS layer

In this article we report on a semitransparent polymer solar cell (STPSC) with polymer: fullerene blends sandwiched between a bottom one-dimensional photonic crystal (1DPC) and a top solution-processed highly conductive PEDOT:PSS electrode for light harvesting. The photoelectric parameters of STPSCs are characterized by the measurements of double-face optical transmittance, reflectance, absorption, J-V, EQE, IQE, average visible transmittance, and CIE in conjunction with those of the theoretical calculations based on transfer matrix simulation. The results reveal that the theoretical short-circuit current density (JSC) of 1DPC-STPSC is not sensitive to the active layer thickness due to the relatively weaker microcavity effect compared to that of the conventional opaque PSCs, making the large-area manufacturing process easier. However, it shows a stronger microcavity effect compared to the non-microcavity STPSCs, which is advantageous to light absorption in active blends in the strong absorption band while maintaining visible light transmission in the weak absorption band. The power conversion efficiency of 5.20% and JSC of 12.25 mA cm-2 increased by 37% and 38% respectively when compared with those of the STPSCs without using 1DPC, which is the highest value ever reported for an inverted STPSC with a low-cost highly conductive PEDOT:PSS layer as the light-incident side.