A Bilayer LiF/C 60 Interfacial Strategy for High Efficiency Inverted PbS QD Photodetectors

This study proposes a bilayer interface engineering strategy that significantly enhances device performance in inverted PbS quantum dot photodetectors through the incorporation of an ultrathin LiF layer and a conventional C₆₀ layer. The LiF/C₆₀ bilayer structure effectively passivates surface traps, improves film flatness, and ensures favorable energy level alignment and efficient electron extraction. Experimental results demonstrate that devices employing this strategy exhibit nearly an order of magnitude reduction in dark current, an increase in external quantum efficiency from 15.45% to 28.90%, and a specific detectivity exceeding 8.47×10¹¹ Jones—representing a more than sixfold improvement compared to unmodified devices.