Mohsen Sajadnia, Sajjad Dehghani, Zahra Noraeepoor and Mohammad Hossein Sheikhi
The purpose of this study is to design and optimize copper indium gallium selenide (CIGS) thin film solar cells.
Abstract
Purpose
The purpose of this study is to design and optimize copper indium gallium selenide (CIGS) thin film solar cells.
Design/methodology/approach
A novel bi-layer CIGS thin film solar cell based on SnS is designed. To improve the performance of the CIGS based thin film solar cell a tin sulfide (SnS) layer is added to the structure, as back surface field and second absorbing layer. Defect recombination centers have a significant effect on the performance of CIGS solar cells by changing recombination rate and charge density. Therefore, performance of the proposed structure is investigated in two stages successively, considering typical and maximum reported trap density for both CIGS and SnS. To achieve valid results, the authors use previously reported experimental parameters in the simulations.
Findings
First by considering the typical reported trap density for both SnS and CIGS, high efficiency of 36%, was obtained. Afterward maximum reported trap densities of 1 × 1019 and 5.6 × 1015 cm−3 were considered for SnS and CIGS, respectively. The efficiency of the optimized cell is 27.17% which is achieved in CIGS and SnS thicknesses of cell are 0.3 and 0.1 µm, respectively. Therefore, even in this case, the obtained efficiency is well greater than previous structures while the absorbing layer thickness is low.
Originality/value
Having results similar to practical CIGS solar cells, the impact of the defects of SnS and CIGS layers was investigated. It was found that affixing SnS between CIGS and Mo layers causes a significant improvement in the efficiency of CIGS thin-film solar cell.
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Mohammad Hossein Rahmati and Mohammad Reza Jalilvand
Current models of organizational excellence are appropriate for the private organizations. It is evident that if an appropriate model is not adopted, the process of excellence in…
Abstract
Purpose
Current models of organizational excellence are appropriate for the private organizations. It is evident that if an appropriate model is not adopted, the process of excellence in the organizations fails and some dimensions of the organization get affected by unpredictable damages. This research aims to identify an appropriate excellence model for public organizations.
Design/methodology/approach
First, a comprehensive literature review was conducted to identify the excellence criteria and models. Second, the models were through an expert-oriented questionnaire, analyzed by the analytical hierarchy process (AHP) technique. Participants were experts in the two domains of excellence models and public sector management. A sample of 15 experts was selected using purposive sampling. In order to emphasize on reliability, 10 questionnaires were adopted for analysis.
Findings
The findings showed that the European Foundation for Quality Management (EFQM) model is the most appropriate model for excellence measurement in the public organizations based on the five selected indices.
Originality/value
The identification of a model for measuring organizational excellence for public sector can significantly contribute to existing literature on excellence measurement.