Langmuir–Blodgett Graphene-Based Films for Algal Biophotovoltaic Fuel Cells

Abstract

The prevalence of photosynthesis, as the major natural solar energy transduction mechanism or biophotovoltaics (BPV), has always intrigued mankind. Over the last decades, we have learned to extract this renewable energy through continuously improving solid-state semiconductive devices, such as the photovoltaic solar cell. Direct utilization of plant-based BPVs has, however, been almost impracticable so far. Nevertheless, the electrochemical platform of fuel cells (FCs) relying on redox potentials of algae suspensions or biofilms on functionalized anode materials has in recent years increasingly been demonstrated to produce clean or carbon-negative electrical power generators. Interestingly, these algal BPVs offer unparalleled advantages, including carbon sequestration, bioremediation and biomass harvesting, while producing electricity. The development of high performance and durable BPVs is dependent on upgraded anode materials with electrochemically dynamic nanostructures. However, the current challenges in the optimization of anode materials remain significant barriers towards the development of commercially viable technology. In this context, two-dimensional (2D) graphene-based carbonaceous material has widely been exploited in such FCs due to its flexible surface functionalization properties. Attempts to economically improve power outputs have, however, been futile owing to molecular scale disorders that limit efficient charge coupling for maximum power generation within the anodic films. Recently, Langmuir–Blodgett (LB) film has been substantiated as an efficacious film-forming technique to tackle the above limitations of algal BPVs; however, the aforesaid technology remains vastly untapped in BPVs. An in-depth electromechanistic view of the fabrication of LB films and their electron transference mechanisms is of huge significance for the scalability of BPVs. However, an inclusive review of LB films applicable to BPVs has yet to be undertaken, prohibiting futuristic applications. Consequently, we report an inclusive description of a contextual outline, functional principles, the LB film-formation mechanism, recent endeavors in developing LB films and acute encounters with prevailing BPV anode materials. Furthermore, the research and scale-up challenges relating to LB film-integrated BPVs are presented along with innovative perceptions of how to improve their practicability in scale-up processes.

Recent Advance in Electrochromic Materials and Devices for Display Applications

“…This solid monolayer can be transferred to a solid substrate via an impregnation process. [70] The hydrophilic end of the amphiphilic material is generally À COOH, À SO 4 Na, À COONa, À SO 3 Na, À N, À OH, and so on, and the hydrophobic group is generally À CH 2 À , À CH=CHÀ , À CH 2 =COÀ CH 2 À , À CF 2 À , À CF 3 , etc. The LÀ B technique excels in controlling film thickness, facilitating the fabrication of both single-layer and multilayer films.…”

Controllable-assembled functional monolayers by the Langmuir–Blodgett technique for optoelectronic applications

“…50,139,140 Graphene and its oxide nanosheets are typical 2D materials. Since its discovery in 2004, 141 graphene has been active as a promising material in various fields such as electrochemical storage, 142 sensitive response sensor devices, 143 and optoelectronic devices 144 due to its excellent characteristics such as low cost, high specific surface area, high electrical conductivity, and high transmittance. 141 The chemical vapor deposition (CVD) method is commonly used to produce graphene nanosheets or other 2D materials on specific substrates and arealimited regions, restricting the scope of applications of twodimensional materials.…”

The Efficiency Study of Graphene Synthesis on Copper Substrate via Chemical Vapor Deposition Method with Methanol Precursor

“…Graphene can be conducted as a kind of functional material for flexible and transparent devices due to its unique structures, excellent physical properties, and terrific mechanical and flexible characteristics, which result in lots of potential applications in the fields of biosensors [ 1 , 2 ], supercapacitors [ 3 ], liquid crystal devices [ 4 ], electronic devices [ 5 ], solar cell [ 6 , 7 ], catalysts [ 8 ], and even in energy storage and battery applications [ 9 ]. Owing to the sp 2 bonds and π bond with carbon atoms tightly and regularly arranged in a single layer of hexagonal honeycomb-like, two-dimensional structures [ 10 ], the electrons in graphene can move freely which result in an excellent electrical conductivity and very high mobility at room temperature [ 11 , 12 ].…”