Meeting the Clean Energy Demand:  Nanostructure Architectures for Solar Energy Conversion

Abstract

The increasing energy demand in the near future will force us to seek environmentally clean alternative energy resources. The emergence of nanomaterials as the new building blocks to construct light energy harvesting assemblies has opened up new ways to utilize renewable energy sources. This article discusses three major ways to utilize nanostructures for the design of solar energy conversion devices: (i) Mimicking photosynthesis with donor−acceptor molecular assemblies or clusters, (ii) semiconductor assisted photocatalysis to produce fuels such as hydrogen, and (iii) nanostructure semiconductor based solar cells. This account further highlights some of the recent developments in these areas and points out the factors that limit the efficiency optimization. Strategies to employ ordered assemblies of semiconductor and metal nanoparticles, inorganic-organic hybrid assemblies, and carbon nanostructures in the energy conversion schemes are also discussed. Directing the future research efforts toward utilization of such tailored nanostructures or ordered hybrid assemblies will play an important task in achieving the desired goal of cheap and efficient fuel production (e.g., solar hydrogen production) or electricity (photochemical solar cells).

Nanocompósitos semicondutores ZnO/TiO2: testes fotocatalíticos

“…Algumas aplicações de grande relevância envolvendo o semicondutor TiO 2 são: fotocatálises assistidas por semicondutor para produzir combustíveis, tais como hidrogênio e, células solares baseadas em nanoestruturas de semicondutor. 3 O princípio de funcionamento do TiO 2 como fotocatalisador baseia-se na geração do par elétron-lacuna positiva, através da absorção de energia. 4 A luz UV é a fonte de energia mais comumente empregada.…”

“…26 Uma estratégia que vem sendo utilizada para melhorar a eficiência do processo fotocatalítico devido a melhor separação de cargas é a obtenção de nanocompósitos do tipo metal/ TiO 2 e semicondutor/TiO 2 . 3 Um filme compósito nano-ZnO/TiO 2 para ser aplicado como fotocatalisador foi fabricado pelos métodos de vaporização a vácuo e sol-gel. O nanofilme ZnO/TiO 2 melhorou a eficiência de separação de carga e estendeu o intervalo do espectro, o qual mostrou uma alta eficiência no processo fotocatalítico, melhor que os filmes de nano-TiO 2 puro e nano-ZnO puro.…”

Nanoscale Effects in Water Splitting Photocatalysis

“…The third strategy is to exploit scaling laws and specific effects at the nanoscale [53][54][55][56] to overcome the limiting problems of metal oxide absorbers, such as their short electron-hole lifetimes and low mobility. This nanostructuring strategy has gained significant interest in the last 20 years [57][58][59][60][61][62][63][64][65][66][67] and is the focus of this chapter.…”

“…Because of the problems above, the number of known nanoscale photocatalysts for overall water splitting is limited [57][58][59][60][61][62][63][64][65][66]. Only five nanoscale photocatalysts have been reported in the literature.…”

A review on applications of Cu2ZnSnS4 as alternative counter electrodes in dye-sensitized solar cells

“…Among the various solar cells, dye-sensitized solar cells (DSSCs) have attracted much attention because of its low cost, facile fabrication, faster energy payback time and diverse modification. [6][7][8][9] The basic aim of DSSCs lies on higher solar to electricity conversion efficiencies with lower production costs, flexibility and eco-friendliness. The key idea of the technology being photoelectrochemical in nature closely resembles with natural photosynthesis process.…”