Role of hexamine in ZnO morphologies at different growth temperature with potential application in dye sensitized solar cell

Zinc oxide (ZnO) is a potential semiconductor being investigated for a variety of applications as many are dependent upon its typical shape. Using hydrothermal method, ZnO nanorods are grown using equimolar solutions of Zinc nitrate and Hexamethylenetetramine (HMTA). This study aims to investigate the effects of temperature on morphology of the zinc oxide structures. HMTA beyond acting as a pH buffer, creates a steric interference at lower temperature which gives space for nanorod growth. At higher temperature, this effect is dominated by the excess of ammonia involvement cancelling the non-polar chelation thereby resulting in rice shaped structures. These structures were characterized by SEM, XRD, RAMAN spectroscopy, UV-Vis spectroscopy and photoluminescence. The dye-sensitized solar cell (DSSC) performance is also studied. It is stipulated that though the nanorods show better efficiency, microrice has potential space for improvement.