Abstracts Book - IMRC 2018

• SC4-P078
EFFECT OF THE SOLUTION pH ON THE PROPERTIES OF ZnS THIN
FILMS SYNTHESIZED BY A NON-TOXIC CHEMICAL BATH DEPOSIT
Carlos Rodríguez 1 , Claudia Carrasco 2 , Marcos Flores 3
1 Universidad de La Serena, Multidisciplinary Research Institute for Science and Technology,
Chile. 2 Universidad de Concepción, Departamento de Ingeniería de Materiales, Chile.
3 Universidad de Chile, Departamento de Física, Chile.
ZnS films have shown great potential to be used as a buffer layer in thin film
solar cells (TFSC). Even though, ZnS films have been grown using various
techniques, the Chemical Bath Deposition (DBQ) method achieves greater
energy conversion efficiency in TFSC devices. However, the synthesis of this
compound normally includes toxic and highly volatile elements, such as
ammonia and hydrazine. Accordingly, synthesis of ZnS thin films free of toxic
precursors has been under intense investigation. In this work ZnS films were
synthesized free of toxic precursors by means of chemical bath deposition
method. The solution pH was varied 9 to 11.5 by adding appropriate amount of
KOH. The influence of the solution pH on the optical and morphological
properties of the ZnS thin films were analyzed by means of UV-Vis
spectrophotometry and scanning electron microscopy (SEM). The films
exhibited a higher percentage of optical transmission in the visible range (higher
than 80 %). From the morphological studies, compact samples were observed
with well-defined particles for pH values between 9.5 and 10.5. It was also
observed that samples grown at pH 9 did not cover homogenously the substrate
surface, and samples grown at pH values higher than 11 exhibited a high density
of cracks. From the results mentioned above, it is clear that the samples grown
at pH between 9.5 and 10.5 are the most suitable for thin films solar cells
applications.
Acknowledgment:
This work was supported by CONICYT through the project FONDECYT Iniciación
11160368.
Keywords: ZnS thin films, chemical bath deposition, optical properties
Presenting authors email: arodriguez@userena.cl