Multi-junction Tandem Cells Research Articles

Research progress of perovskite-based triple-junction tandem solar cells

The energy conversion efficiency of single-junction solar cells is limited by the Shockley-Queisser theory and the most effective strategy to break through this limit is to fabricate multi-junction tandem solar cells. Perovskite materials offer a continuously tunable energy band structure, which provides a new option for light-absorbing materials in multi-junction tandem cells. In the field of perovskite-based multi-junction tandem solar cells, triple-junction tandem solar cells demonstrating immense potential. The present paper introduces the configuration of triple-junction solar cells and addresses three scientific challenges. 1）Ensuring energy level alignment among sub-cells is a critical concern for three-junction batteries. Specifically, the top wide-band gap sub-cell must possess a band gap ranging from 1.8eV to 2.2eV; however, current perovskite material systems with wide-band gaps exhibit certain defects. 2） attaining current matching in multi-junction tandem solar cells while optimizing the absorption layer and minimizing parasitic absorption is essential to maximize solar cell current output. 3） The functional layers of multi-junction tandem solar cells are sequentially stacked using different deposition methods, thereby imposing higher compatibility requirements on the intermediate interconnect layer. Subsequently, the research progress of perovskite-based triple-junction tandem solar cells is then presented, encompassing perovskite/perovskite/silicon tandem solar cells, perovskite/perovskite/organic tandem solar cells, and all-perovskite tandem solar cells. Their respective highest efficiencies are 19.4%, 23.87%, and 27.1%. Finally, this paper examines the research direction for further enhancing the performance of triple-junction solar cells. In addition to augmenting energy conversion efficiency, perovskite-based solar cells must address stability issues in order to achieve future commercialization, thereby offering guidance for the development of efficient triple-junction cells.

Recent progress and future prospects of perovskite tandem solar cells

Organic–inorganic metal halide perovskite solar cells represent the fastest advancing solar cell technology in terms of energy conversion efficiency improvement, as seen in the last decade. This has become a promising technology for next-generation, low-cost, high-efficiency photovoltaics including multi-junction tandem cell concepts. Double-junction tandem cells have much higher efficiency limits of 45%, beyond the Shockley–Queisser limits for a single-junction solar cell. In this review, recent progress with the perovskite tandem solar cells is highlighted, in particular, with 2-terminal perovskite–Si, perovskite–CIGS [where CIGS = Cu(In,Ga)(S,Se)2], perovskite–organic photovoltaic, perovskite–perovskite, and 3-junction-perovskite tandems. The opportunity and challenges of two-terminal monolithic perovskite tandems are discussed including a roadmap of strategies for further improving their efficiencies.

Photovoltaic Power Generation: The Impact of Nano-Materials

Solar power is seen by many as a solution to the world’s energy problems. The earth receives 1.7x1017W from the sun compared to a total electricity generation capacity of 4.6x1012W (OECD prediction for 2010). However the average power density is low with a daytime average over the earth of 680Wm-2. This makes centralised generation problematic but distributed photoelectric generation by domestic and commercial users is a rapidly developing market. However typical commercially available modules have an energy conversion efficiency of less than 12%. Silicon cells with 24% efficiency have been produced in the lab while multi-junction tandem cells using different semiconductor materials (GaInAs, GaInP and Ge) to absorb different parts of the sun’s spectrum have reached 40%. This chapter describes some of the materials and device achievements so far and looks at possible ways in which higher efficiencies might be achieved with particular emphasis on nano-materials to use more of the solar spectrum efficiently. The possibility of using quantum slicing and multiple exciton generation to make more efficient use of high energy photons is considered and impurity band generation as a possible route to use low energy photons. One of the greatest challenges is to do this cheaply using semiconductors made from non-toxic abundant elements.