Nanocellulose and Nanochitin Cryogels Improve the Efficiency of Dye Solar Cells

Abstract

Biobased cryogel membranes were applied as electrolyte holders in dye solar cells (DSC) while facilitating carrier transport during operation. They also improved device performance and stability. For this purpose, cellulose nanofibers (CNF), TEMPO-oxidized CNF (TOCNF), bacterial cellulose (BC), and chitin nanofibers (ChNF) were investigated. The proposed materials and protocols for incorporating the electrolyte, via simple casting, avoided the typical problems associated with injection of the electrolyte through filling holes, a major difficulty especially in manufacturing large area cells. Owing to the fact that cryogel membranes did not require any orifice for injection, they were effective in minimizing leakage and in retaining liquid electrolyte. The results indicated the reduction of performance losses compared to conventional electrolyte filling, likely due to the better spatial distribution of electrolyte. DSCs based on BC cryogels had an initially higher performance and similar stability compared to those of the reference cells. When compared to reference cells, CNF and ChNF cryogels produced higher initial performance, but they underwent a faster degradation. The difference in stability was attributed to the effect of residual components, including lignin in CNF and proteins in ChNF, as demonstrated in bleaching experiments. TOCNF indicated a relatively poor performance, most likely because of residual aldehydes. Overall, we offer a comprehensive evaluation based on current−voltage (IV) profiles under simulated sunlight, incident photon-to-charge carrier efficiency (IPCE), electrochemical impedance spectroscopy (EIS), and color image processing, together with accelerated DSC stability tests, to unveil the effects of new membrane-based assembly. Our results give guidelines for future developments related in particular to the effects of the tested biomaterials on device stability.

Advances of RRAM Devices: Resistive Switching Mechanisms, Materials and Bionic Synaptic Application

“…In general, organic materials and inorganic materials are two main categories of RS medium, as illustrated in Figure 6. Research of RS medium based on organic materials mainly focuses on biological materials (silk protein/fibroin, nanocellulose and albumen) [65][66][67], polymer materials (PVK (polyvinyl carbazole), PVA (polyvinyl alcohol), PDA (Polydiacetylene), PTH (polythiophene)) [68][69][70][71], and other materials. Chen et al presented an RRAM device fabricated with spin-coated chicken egg albumen layer [67].…”

Extreme sensitivity of dye solar cells to UV‐induced degradation

“…Previous studies prove that a UV filter is necessary to extend the device lifetime since without any filter the cells last only some days (50‐100 hours), 5,28 and here, the devices with the filter lasted ten times longer. But these results raise the question what kind of filter would be sufficient to stabilize the cells.…”

“…Although the amount of transmitted light below 395 nm was below the detection threshold of our spectrometer, it is possible that small amounts of light passed the filter and triggered UV degradation of the cells. Our previous studies with full UV light without any filter indicated that similar DSCs degraded to 20% of their initial efficiency in 200 hours 28 . Since DSCs are extremely sensitive to UV illumination, here even minor UV light might also be the cause of the observed accelerated degradation.…”

Extraction of Nanochitin from Marine Resources and Fabrication of Polymer Nanocomposites: Recent Advances

“…Yet another field that nanochitin finds application includes electrical and electronic devices. For example, biobased cryogel membranes were implemented as electrolyte holders in dye solar cells (DSC) [128], thus facilitating carrier transport during service. It was also observed that the system performance and stability were also improved with the help of chitin nano fibers.…”