Tetraethyl orthosilicate (TEOS), ammonia solution (NH3, 25%),
hexane and anhydrous ethanol (Beijing Chemical Plant) were used
without any further treatment. The glass slides were cleaned in ethanol
by ultrasonic cleaner for 10 min and rinsed with deionized water
for several times, and finally dried with nitrogen gas. The full-sized
solar modules used were products of CEEG (Shanghai) Solar Science
& Technology Co., Ltd. The cover glass for the solar module was the
product of Tianjin Taiyue Glass Co., Ltd.