Since municipal solid waste (MSW) is a negatively priced, abundant, and essentially renewable feedstock, energy recovered from MSW is a useful technology to reduce the consumption of fossil fuels, and also reduces the expenses needed to dispose of MSW. Three configurations of MSW-based IGCC power system (Design 1), MSW-based IGCC polygeneration system (Design 2), and CaO-based IGCC polygeneration system (Design 3) are proposed. Design 1 uses a combination of an identified MSW gasifier, an integrated intermittent chemical-loop air separation (IICLAS), and Rankine and Brayton cycles to generate electricity and achieve the high concentration of CO₂ emissions around 93.3%~94.7%. The process for co-production of DME and MeOH in Design 2, which replaces the Rankine cycle in Design 1, could increase the net energy efficiency of Design 1 by 71.6%, but the total CO₂ emissions from Design 2 are merely 7.97% of Design 1. The calcium looping gasification (CaLG) process in Design 3, which replaces the MSW gasifier in Design 2, could increase the production rate of DME of Design 2 by 12.5%. The CO₂ concentration from the calcinator in Design 3 is higher than CO₂ concentration in flue gas from Designs 1 and 2 by 2.0%~3.5%. Through exergy analysis, the overall exergy efficiency of Design 3 is lower than Designs 1 and 2 by 3.2%~10.1% due to the exergy destruction rate and ratio in the gasification zone of Design 3 higher than other designs. The GaLG process could increase the DME yield as well as the outlet CO₂ concentration, but this approach design induces a higher exergy loss.

Perovskite/silicon tandem solar cells have reached certified efficiencies of 28% (on 1 cm² by Oxford PV) in just about 4 years, mostly driven by the optimized design in the perovskite top cell and crystalline silicon (c-Si) bottom cell. In this review, we focus on the structural adjustment of the bottom cell based on the structural evolution of monolithic perovskite/silicon tandem solar cells to improve their performance. To begin with, c-Si solar cells are classified into silicon homojunction and silicon heterojunction (SHJ) devices according to temperature tolerance, and the corresponding structural features are presented. Then, the evolution of monolithic perovskite/silicon tandem cells based on c-Si homojunction and heterojunction bottom devices is summarized. An appropriate candidate of the c-Si bottom cell for monolithic perovskite/silicon tandem cells is proposed, mainly including passivated emitter and rear cell devices, the tunnel oxide passivated contact cell, and SHJ devices. In brief, our review will emphasize the important role of the c-Si bottom cell with different passivation structures for perovskite/silicon tandem cells, which provides a guidance to enhance the performance of tandem cells.