04/2009ChemSusChem is an international journal of chemistry andsustainability, energy and materials. It is co-owned by the Chemistry Publishing Society Europe(ChemPubSoc Europe), supported by the Asian Chemical Editorial Society (ACES), and publishedby Wiley-VCH. Contributions in ChemSusChem cover research at the interface of chemistry andsustainability with energy research, materials science, chemical engineering, biotechnology, andenvironmental research. ChemSusChem publishes Communications and Full Papers, Reviewsand Minireviews, Highlights, Concepts, and Essays, Book Reviews, and Conference Reports.Authors can submit articles to ChemSusChem online. Just go to our homepage(http://www.chemsuschem.org), click on “Online Submission of Manuscripts”, and follow thesimple instructions.

All of the articles in this issue have already appeared online in Wiley InterScience.See http://www.chemsuschem.org under EarlyView�

Full text :

http://www.interscience.wiley.com

DOI: 10.1002/cssc.200900074

The XXI Challenge: Cheap and RenewableEnergy SourcesEmilio Palomares*[a, b]

As the world comes to terms with the unprecedented eco-nomic crisis it currently faces, the issue of global warming is indanger of being put in the background. However, not to con-tinue our efforts of dealing with this issue and not keeping itin the consciousness of our governments as well as society as

a whole would be monumentalerrors. Indeed, the need to find analternative source of energy to thefinite and greenhouse-gas-produc-ing fossil fuels is perhaps just as im- Dr. Emilio Palomares

ChemSusChem 2009, 2, 267 – 271 � 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 267

portant to the current world economic model as the threatsposed by the ‘credit crunch’.

The need to establish a sustainable globalized economybased on optimized clean chemical processes and cheap re-newable energy sources is generally recognized. The formerissue has been previously discussed in ChemSusChem, and forthe latter we give in this issue a flavor of the basic researchthat is currently being developed for using the most abundantenergy source present on our planet: sunlight.

Much effort has been devoted to the use of sunlight as anenergy source, either through the production of fuels (hydro-gen) or by direct conversion into electrical power. However,despite many advances photovoltaic technologies require fur-ther development to be economically viable. In this issue ofChemSusChem we can already foresee the directions that sev-eral important research groups are taking to achieve this aim.Contributions to this Special Issue come form Prof. Torres(near-infrared dyes for efficient capture of low-energy pho-tons), Prof. Domen (water splitting for hydrogen generation),Dr. Nazeeruddin and Prof. Gr�tzel (low-cost molecular photo-voltaic devices), and many other authors whose contributionsclearly show the importance of basic and fundamental re-

search that still is needed to succeed in this challenge: A chal-lenge for 21st century scientists.

I would personally also like to acknowledge those groups that,despite working on the same topics covered by this SpecialIssue, are not directly represented. However, their outstandingwork is cited in the References sections of the manuscriptsthat make up the ChemSusChem Special Issue on Chemistryand Energy in the 21st Century.

On behalf of the editorial team, I hope that you enjoy thisissue and I look forward to reading your future achievements.

Emilio PalomaresTarragona, Spain, March 2009.

[a] Prof. E. PalomaresL1.1.6 LaboratoryInstitute of Chemical Research of Catalonia (ICIQ)Avda. Pa�sos Catalans 16, Tarragona 43007 (Spain)Fax: (+ 34) 977 920 200E-mail : e.palomares@iciq.es

[b] Prof. E. PalomaresInstituci� Catalana de Recerca i Estuids AvanÅats (ICREA)Avda. Llu�s Companys 28, Barcelona 08080 (Spain)

268 www.chemsuschem.org � 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim ChemSusChem 2009, 2, 267 – 271