Strategic Evolution of Quantum Dot-Sensitized Solar Cells From Materials to Devices

Quantum dot-sensitized solar cells (QDSSCs) have emerged as a promising next-generation photovoltaic technology, utilizing semiconductor quantum dots (QDs) for efficient light energy conversion. Their high absorption coefficients, tunable bandgaps, and multiple exciton generation (MEG) properties offer significant advantages. According to the National Renewable Energy Laboratory (NREL) report, early QDSSCs achieved an efficiency of only 1.35%, while recent advancements have pushed to their power conversion efficiency (PCE) to nearly 18.1%, driven by innovations in photoanode engineering, interface optimization, and novel QDs materials. Strategies to maximize photoinduced charge separation and electron transfer, as well as minimize recombination losses through interface engineering, are analyzed. The challenges of maintaining long-term stability, reducing recombination, and addressing environmental concerns are also discussed, with attention to protective coatings, encapsulation techniques, and lead-free QDs alternatives. Significant progress has been achieved using quaternary Cu₂ZnSnS₄ (CZTS) QDs in QDSSCs. The use of 1-dodecanethiol (DDT) as a capping ligand, followed by a successive ionic layer adsorption and reaction (SILAR) process to create a core/shell structure, has enhanced charge transport and reduced recombination. The integration of QDSSCs with tandem solar cells and improvements in charge carrier extraction could unlock higher efficiencies, advancing the role of QDSSCs in delivering sustainable and cost-effective solutions.