Acronym: EECSC-23

Project code: PN-III-P1-1.1-PD-2021-0240

Project Director: Dr. Mohamed Yassine Zaki

Project advice: National

Framework program of the project: P1 - Development of the national CD system - Human resources - Postdoctoral research projects (PD)

Funded by: Executive Unit for the Financing of Higher Education, Research, Development and Innovation, UEFISCDI

Contractor: National Institute og Materials Physics

Status: Ongoing

Start date: 01.04.2022

Closing date: 31.03.2024

Abstract:

Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) based solar cells have attracted a lot of interest lately due to their promising potential and similar properties to the better known Cu(In,Ga)Se2 (CIGS) and CdTe photovoltaic devices. However, these materials suffer from the omnipresence of several secondary phases that influence their performances. The champion device has a 12.6% power conversion efficiency, which is still much lower than its counterpart CIGS. The objective of this project is the enhancement of the efficiency of CZTSSe thin films solar cells via PN junction layers engineering. The CZTSSe p-type absorber layers will be deposited using a two-steps magnetron sputtering deposition followed by a sulfurization/selenization in order to avoid the secondary phases and obtain stoichiometric films. Cadmium sulfide (CdS) is commonly used as a n-type layer for kesterite solar cells, but owing to Cd toxicity, ZnS or ZnSe materials are proposed here. Tuning the band alignment at the interface between the p-type and n-type layers will be done by varying the thickness and band gap of the buffer layer in order to achieve high efficiency CZTSSe solar cells. The findings of this project will be useful to understand the relation between the synthesis conditions, composition and the formation of secondary phases. This will guide the design of new ecological solar cells with an improved efficiency that can reach the commercial panels requirements.

Objective:

- Synthesis of pure and highly crystalline CZTSSe thin films with the adequate stoichiometry and no secondary phases.
- Substitute the usual toxic buffer layer material (CdS) with a eco-friendly compound (ZnS/ZnSe).
- Fabrication of high efficiency solar cells using the elaborated CZTSSe absorber and ZnS/ZnSe buffer layers.

Estimated result:

- Recipe development of CZTSSe thin films without secondary phases.
- Investigating the use of ZnS and ZnSe buffer layers in kesterite solar devices.
- Finding solutions for PCE enhancement of the CZTSSe-based solar cells;
- Publication of two ISI articles.