Towards the commercialization of colloidal quantum dot solar cells: perspectives on device structures and manufacturing
Over the past decade, colloidal quantum dot solar cells (CQD-SCs) have been developed rapidly, with their performances reaching over 16% power conversion efficiency. Accompanied by the development in materials engineering (CQD surface chemistry) and device physics (structures and defect engineering), CQD-SCs are moving towards commercialization. A broad overview of the requirements for commercialization is thus timely and imperative. Broad comprehension of structure engineering, upscaling techniques, stability and the manufacturing cost of CQD-SCs is necessary and should be established. In this review, the development of device structures is presented with their corresponding charge transfer mechanisms. Then, we overview the upscaling methods for the mass production of CQD-SCs. Comparisons between each of the upscaling techniques suggest the most advanced process close to industrialization. In addition, we have investigated the origin of the photovoltaic (PV) performance degradation. The possible degradation sources are categorized according to external environmental factors. Moreover, strategies for improving the stability of CQD-SCs are presented. In the conclusion, we have reviewed the cost-effectiveness of CQD-SCs in terms of the niche PV market. Step-wise manufacturing cost analysis for the commercial CQD-SCs is presented. In the conclusion, the future direction for environment-friendly CQD-SCs is discussed.