Much attention has been recently focused on realizing, by chemical treatment, an artificial superhydrophobic surface with elevated roughness in order to achieve both self cleaning and antireflective effects because superhydrophobic surface with surface functionalization is believed to be effective for the self cleaning effect, mimicking a lotus leaf. Various hydrophobic, hydrophilic, superhydrophobic, and superhydrophilic glasses are evaluated by monitoring the variation of water contact angle (CA), optical transmittance, and photovoltaic performance under outdoor conditions for 12 weeks. Our results show a nanopatterned superhydrophilic glass without surface chemical treatment exhibits more efficient self cleaning and antireflective effects, leading to only 1.39% of drop of solar cell efficiency during an outdoor test for 12 weeks, while the solar cells with bare glass packaging and fluorinated superhydrophobic packaging show 7.79% and 2.62% of efficiency drop, respectively. (C) 2011 Elsevier B.V. All rights reserved.