No abstract

The liquid electrolyte causes the corresponding leakage and sealing problems in the construction of dye-sensitized solar cells (DSSCs). Currently, quasi-solid-state polymer-based electrolytes have been reported to effectively improve the leakage and volatilization of traditional liquid electrolytes in DSSCs. In this work, reduced graphene oxide (rGO) and the intercalation of MXene/rGO were utilized in the copolymer polyethylene oxide/poly(vinylidene fluoride-co-hexafluoropropylene) as a printable gel electrolyte for the preparation of quasi-solid-state DSSCs (QS-DSSCs). The effects of different contents of rGO and different ratios of MXene/rGO intercalation on the photoelectric performance of DSSCs were well studied. When the rGO content was 0.5 wt %, the power conversion efficiency (PCE) of DSSC was about 7.781%. Specifically, when the ratio of MXene/rGO was 2/1, the photovoltaic performance of DSSCs was greatly enhanced. The corresponding short current density (J sc ), open-circuit voltage (V oc ), fill factor, and PCE were obtained to be 15.170 mA/cm 2 , 0.783 V, 0.695, and 8.255%, respectively. With the intercalation structure between MXene and rGO, the conductivity of electrolytes seemed to be improved through the possible shortening of transmission and diffusion distance of electrolyte ions. The printable electrolyte could achieve an energy conversion efficiency of 29.94% under 1000 lux illumination. A long-term stability (>95%) of QS-DSSCs was also achieved with the composite of MXene/rGO over 1000 h. Finally, this ready screen-printing technology with the electrolyte of the MXene/rGO composite in the copolymer would have great potential for the large-scale manufacture of flexible DSSCs in the future.

Currently, the high cost and the time-consuming preparation of electrolytes of quasi-solid-state dye-sensitized solar cells (QS-DSSCs) remain the key issue for the large-scale commercial fabrication of DSSCs. In this work, we propose a quasi-solid electrolyte based on a conductive melamine formaldehyde (MF) sponge scaffold for the fabrication of QS-DSSCs, which are MXene-MF, rGO-MF and PEDOT:PSS-MF. The three-dimensional porous structure in MF can quickly adsorb and store electrolytes, which shows high wettability, high organic solvent saturated adsorption capacity, and high electrical transmission performance. Specifically, the quasi-solid electrolyte prepared by this method can shorten the preparation method to less than 0.5 s, which also significantly reduces the preparation cost of the quasi-solid electrolyte. The QS-DSSC photoelectric conversion efficiency (PCE) of the melamine formaldehyde sponge can reach up to 7.822%. As compared with other conductive materials, MXene-MF is demonstrated to effectively improve the transmission performance of photogenerated electrons in the external circuit and the counter electrode interface. Meanwhile, the QS-DSSC based on MXene-MF has high catalytic activity, exchange current density, and IPCE. Specifically, the PCE reaches 26.92% under the indoor lighting condition of 1000 lux. Additionally, the QS-DSSC based on the composite sponge quasi-solid electrolyte exhibits excellent optoelectronic properties and long-term stability up to 90% in 1000 h. Finally, these QS-DSSCs based on the conductive MF sponge will have great promising potential in renewable energy applications such as flexible batteries and intelligent buildings.

No abstract

Double-response thermosensitive microcapsules based on hydrogel were prepared by environmental-friendly physical and chemical methods. It can induce reversible discoloration or expansion feedback at different temperatures.