Large-area nanopatterning is introduced on a flexible gold substrate by block copolymer (BCP) lithography. We fabricate ultrahigh power energy harvesting nanogenerators based on contact-electrification principle exploiting the effective contact area enhancement by block copolymer lithography. Owing to the facile and effective surface area enhancement by BCP nanopatterning, significant enhancement of triboelectric charge induction is attained. Output currents from TENG increased at least 16 times after BCP nanopatterning. This nanogenerator can generate remarkably high output voltage and current, which can directly light up 504 serially connected LEDs. The resultant nanogenerator attains the maximum instantaneous current of 1.6 mA and output power of 93.2 W/m(2). Electrical energy generated by single cycle of impact force is 0.54 mJ, and the average electrical energy is 114.89 mW. Those values indicate one of the highest device performance ever reported for the TENGs based on contact-separation mode thus far. (C) 2015 Elsevier Ltd. All rights reserved.