Poly(3,4-ethylenedioxythiophene) Quantum Dot-Sensitized Solar Cells in the Solid-State Utilizing Polymer Electrolyte

As a new class of sensitizers, poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(hydroxymethyl-3,4-ethylenedioxythiophene) (PEDOT-OH) quantum dots (QDs) are successfully introduced for solid-state QD-sensitized solar cells utilizing polymer electrolyte with I-/I-3(-) redox couple for the first time. These two polymer QDs were prepared by facile top-down nanoprecipitation method from dodecyl sulfate-doped PEDOT and PEDOT-OH nanofibers. In particular, PEDOT-OH QDs containing -OH anchoring groups have a wider range of light absorption, and tighter adsorption onto the TiO2 surface, compared to PEDOT QDs, yielding higher photocurrent density and consequently higher energy conversion efficiency beyond 1% under 1 sun conditions, which is higher than that of most carbon nanodot sensitizers ever reported. Interestingly the range of the light absorption is further broadened by spontaneous re doping the polymer QDs by I-2 and/or I-3(-) dissolved in the polymer electrolyte. Moreover, QDSCs utilizing both polymer QDs show excellent long-term stability over 360 min. These results suggest a new avenue to utilize common polymer QDs as a new sensitizer for solar cells, and therefore much higher efficiency is expected to be achieved by optimizing the structure of polymer QDs and the configuration of corresponding devices.