Review of recent progress in enhanced quantum dot solar cells via plasmonic nanostructures

One attractive method for enhancing photon harvesting capacities in quantum dot (QD) photovoltaics is through the integration of plasmon enhanced nanostructures. Quantum Dot Solar Cells (QDSCs) possess unique qualities including multiple electron-hole pair generation, photoluminescence and tunable energy gap that can make them suited for energy devices potentially leading to enhanced efficiency. QDSCs due to its potential can surpass the theoretical limit but the challenges in charge carrier separation and transport limit its efficiency. These limitations prevent QDSCs from fully overcoming the fundamental efficiency limit for single-junction solar cells. Surface plasmons are beneficial for enhance light absorption and their nonradiative decay process generate hot electrons. Plasmonic metals have recently been added to QDSCs for better efficiency. The plasmonic resonances in metallic nanostructures allow light absorption, scattering and generation of localized electromagnetic field enhancements within QDSCs to reduce recombination and transition losses. This review examines the recent progress in plasmonic nanostructures for QDSCs, with focus on quantum dot properties, common synthesis routes and the three principal architectures of QDSCs namely; sensitized, depleted heterojunction and Schottky-type configurations. The underlying enhancement mechanisms, including optical field enhancement, scattering-induced light trapping, hot-electron injection and plasmon-induced resonance energy transfer were also discussed. Depending on plasmonic design and device architecture, comparative efficiency summaries are discussed relative to the Shockley–Queisser limit to assess the extent and limitations of plasmonic gains. Key fabrication and stability challenges are discussed and finally future research directions toward achieving next-generation high-performance photovoltaic devices are outlined.