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–/I3– 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 I2 and/or I3– 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