Rational construction of porous amorphous WO3 nanostructures with high electrochromic energy storage performance: Effect of temperature

Compared to conventional direct current (DC) and radio frequency (RF) magnetron sputtering, the pulsed radio frequency (PRF) magnetron sputtering circumvents the obstacle of a self-annealing temperature effect during the deposition, which may induce irregular crystallization or uneven chemical composition. The porous homogeneous amorphous WO3 film prepared by the PRF magnetron sputtering shows large dual-band optical modulation in the visible and near infrared regions(93.6% in 633 nm and 90.6% in 1500 nm), short response time (3.2s for coloring and 5.6s for bleaching), decent coloration efficiency(56.8 cm( )(2)C(-1)) and superior cycling stability(the optical modulation is dropped by 4.3% after 2000 cycles). In addition, the PRF WO3 film also presents good energy-storage properties (44.0 mF/cm(2) areal capacitance), good capacitive cyclic stability without apparent capacitance loss after 2000 cycles and superior rate capability. The obtained bi-functional porous amorphous WO3 film may find great potential in constructing high efficiency electrochromic energy storage and other intelligent nanodevices.