@article { ISI:000361697400005, title = {Fractional photo-current dependence of graphene quantum dots prepared from carbon nanotubes}, journal = {Physical Chemistry Chemical Physics}, volume = {17}, number = {38}, year = {2015}, month = {AUG}, pages = {24566-24569}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We report on the photo-conductivity studies of chemically synthesized graphene quantum dots (GQDs) of average size 12 nm obtained by the oxidative acid treatment of MWCNTs. The dependence of photocurrent I-ph (I-ph = I-ill - I-dark) on the laser intensity P under a wide range of laser intensities (5 mW \<= P \<= 60 mW) shows a fractional power dependence of I-ph on light intensity. The temperature dependence (300 K \< T \< 50 K) of I-ph observed in thin films of these GQDs indicates that in the higher temperature region (T \> similar to 100 K), as the temperature increases, the number of thermally generated carriers increase resulting in increased I-ph. At sufficiently low temperatures (T \<= 100 K), a constant I-ph is observed, indicating a constant photocarrier density. Such a behavior is typically observed in many photoactive disordered semiconductors, which are often used in a variety of applications. We believe that the investigations presented here will enhance our understanding of the photocurrent generation phenomenon in chemically obtained GQDs.

}, issn = {1463-9076}, doi = {10.1039/c5cp03306c}, author = {Kundu, Sumana and Ghosh, Sujoy and Fralaide, Michael and Narayanan, T. N. and Pillai, Vijayamohanan K. and Talapatra, Saikat} }