Evolution of a facile and novel general strategy for fabricating single and mixed 3d-block transition metal hydroxide/oxide films for innumerable applications

Abstract

A single-step, unique, less arduous, and economical strategy has been employed to fabricate floating Co0.33Ni0.67(OH)2 (~536 nm thick) film of predominantly uniform thickness on the surface of a precursor solution via homogeneous nucleation by purging NH3 vapors over it. Subsequently, transferring 1 sq. inch part of as-fabricated films onto the glass substrate, they were transformed into the films of CoNi2O4 by calcining them at a temperature of 300 °C. The transferability of as-formed films on the glass substrate and the robust mechanism to control their thickness assign splendid features to this synthesis technique. A comprehensive study based on the firm footing of experimental observations and findings, pertaining to unfold the inherent mysteries of primary film formation mechanism associated with the employed strategy, has been pursued in this work. In addition to this, due to multitudinous innovative and potential applications in different fields, the promising single and mixed 3d-block transition metal hydroxide/oxide (TMH/TMO) films have triggered an immense enthusiasm amongst the researchers globally for investigating them for the benefit of humanity. Thus, due to this exigency, a trivial novel synthesis strategy is also required for fabricating them. Conceiving an idea from the film formation strategy employed in our previous as well as the current study, this employed strategy has also been generalized for the fabrication of single/mixed 3d-block TMH/TMO films. Uniformity of film thickness, transferability on a desired substrate and reliable mechanism to control the film thickness assign advantageous features to this strategy over the prevailing solution processable film deposition methods and make it more suitable for depositing TMH/TMO films for their versatile applications in the fields of electronics, energy storage and optoelectronics etc.