Understanding the phase formation kinetics of nano-crystalline kesterite deposited on mesoscopic scaffolds via in situ multi-wavelength Raman-monitored annealing

作者：Wang Zhuoran; Elouatik Samir; Demopoulos George P^*

来源：Physical Chemistry Chemical Physics, 2016, 18(42): 29435-29446.

DOI：10.1039/c6cp05759d

Kesterite, a highly promising photo-absorbing crystalline form of Cu2ZnSnS4 (CZTS), has been prepared via various routes. However, the lack of in-depth understanding of the dynamic phase formation process of kesterite leads to difficulties in optimizing its annealing conditions, hence its light harvesting performance. In this paper, in situ Raman monitored-annealing is applied to study the phase formation kinetics of nano-crystalline kesterite from a precursor deposited on a TiO2 mesoscopic scaffold. By performing in situ Raman annealing under different experimental conditions and wavelengths, several facts have been discovered: kesterite crystallization starts at as low as 170 degrees C, but after short time annealing at 300 degrees C followed by cooling, the initially formed kesterite is found to decompose. Annealing at 400 degrees C or higher is proven to be sufficient for stabilizing the kesterite phase. Annealing at the higher temperature of 500 degrees C is necessary though to promote a complete reaction and thus eliminate the parasitic copper tin sulfide (CTS) impurity intermediates identified at lower annealing temperatures. More importantly, the real-time temperature dependence of Raman peak intensity enhancement, shift and broadening for CZTS is established experimentally at 500 degrees C for 1 h, providing a valuable reference in future CZTS research. This work demonstrates the significance of using in situ Raman spectroscopy in elucidating the kesterite phase formation kinetics, a critical step towards full crystal phase control - a prerequisite for developing fully functional CZTS-based optoelectronic devices.

• 出版日期2016-11-14
• 单位McGill