Quantum chemical design of nonlinear optical materials by sp 2 -hybridized carbon nanomaterials: issues and opportunities Shabbir Muhammad, * ab Hong-Liang Xu, * a Rong-Lin Zhong, a Zhong-Min Su, * a Abdullah G. Al-Sehemi c and Ahmad Irfan c Nonlinear optical (NLO) materials are the smartest materials of the era, and have the ability to generate new electromagnetic fields with changed frequencies, phases, and other physical properties. Recently, many cutting edge research reports have been focused on NLO materials especially on those which are composed of sp 2 hybridized carbon nanostructures. As the carbon nanostructures are composed of abundant p-electrons and have significant delocalization, these are potential candidates for modern NLO materials. Generally, sp 2 hybridized carbon nanostructures can be divided into zero-dimensional fullerenes, one-dimensional nanotubes and two-dimensional graphene nanoribbons and quantum dots etc. These dimensionally different carbon nanomaterials are promising candidates for a wide range of applications in next-generation nanotechnologies. In present feature article, we first briefly explain a theoretical structure–NLO property relationship based on perturbation theory and then elucidate the crucial factors to control the NLO responses. We put together the different random investigations of sp 2 hybridized carbon nanostructures for NLO application by highlighting the importance of their several structural designs to tune NLO amplitudes. Furthermore, we make a comparative and updated analysis of the NLO properties of dimensionally different sp 2 hybridized carbon nanomaterials i.e. fullerenes, Dr. Shabbir Muhammad received his MSc in Chemistry from Pakistan. Later, he accom- plished his PhD in Physical Chemistry (2010) with distinc- tion (Nomination for National Excellent Doctoral Dissertation of China) under the supervision of Prof. Zhong-Min Su from Northeast Normal University, China. Dr Shabbir is currently a JSPS Postdoctorate Fellow at the Graduate School of Engineering Science, Osaka University, Japan. He has several academic awards including Global COE (Center of excellence) Fellowship, Young Researcher Award from ISTCP-VII and IBM-Lowdin 2013 Post- doctoral Award from USA. His research interests include the computational study of linear and nonlinear optical properties of nano and organic–inorganic hybrid materials. Prof. Zhong-Min Su received his BS (1983) and then his PhD in inorganic chemistry under the supervision of Prof. Rong-Shun Wang and Prof. Chi-Ming Che from Northeast Normal Univer- sity (1997). He has been a full professor at NENU since 1994. Later, he worked as a visiting scholar in the group of Prof. Chi- Ming Che and Prof. Guan-Hua Chen (The University of Hong Kong), in Prof. Koji Ohta's group (National Industrial Technology Research Institute, Japan), and in Prof. N. Roesch's group (Technical University of Munich, Ger- many). His research interests focus on functional materials chemistry and quantum chemistry. Cite this: DOI: 10.1039/c3tc31183j Received 19th June 2013 Accepted 6th July 2013 DOI: 10.1039/c3tc31183j www.rsc.org/MaterialsC a Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, People's Republic of China. E-mail: shabbir193rb@gmail.com; zmsu@nenu.edu.cn b Department of Materials Engineering Science, Graduate School of Engineering Science Osaka University, Toyonaka, Osaka 560-8531, Japan c Department of Chemistry, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia This journal is ª The Royal Society of Chemistry 2013 J. Mater. Chem. C Journal of Materials Chemistry C FEATURE ARTICLE Published on 06 August 2013. Downloaded by Osaka University on 06/08/2013 14:14:07. View Article Online View Journal