Efficient and Stable PbS Quantum Dot Solar Cells by Triple-Cation Perovskite Passivation

Abstract

Solution-processed quantum dots (QDs) have a high potential for fabricating low cost, flexible and large-scale solar energy harvesting devices. It has recently been demonstrated that hybrid devices employing a single monovalent cation perovskite solution for PbS QD surface passivation exhibit enhanced photovoltaic performance when compared to standard ligand passivation. Herein we demonstrate that the use of a triple cation Cs0.05(MA0.17FA0.83)0.95Pb(I0.9Br0.1)3 perovskite composition for surface passivation of the quantum dots results in highly efficient solar cells, which maintain 96 % of their initial performance after 1200h shelf storage. We confirm perovskite shell formation around the PbS nanocrystals by a range of spectroscopic techniques as well as high-resolution transmission electron microscopy. We find that the triple cation shell results in a favorable energetic alignment to the core of the dot, resulting in reduced recombination due to charge confinement without limiting transport in the active layer. Consequently, photovoltaic devices fabricated via a single-step film deposition reached a maximum AM1.5G power conversion efficiency of 11.3 % surpassing most previous reports of PbS solar cells employing perovskite passivation.

Stability of Quantum Dot Solar Cells: A Matter of (Life)Time

“…Since then, the use of EDT-PbS layer as an HTL has become an important component in many record-setting solar cell devices. [68][69][70][71] Apart from introducing the EDT, Chuang et al [2] laid the focus on another peculiarity of a PbS QD cell, namely that its performance first improves after oxygen exposure and only then starts to decline. This may only in part be attributed to the aforementioned surface oxidation, which initially reduces leakage and recombination.…”

PbS Colloidal Quantum Dot Inks for Infrared Solar Cells

“…The PCE of CQDSCs finally reached 10.5% and maintained high long-term light stability. Recently, Albaladejo-Siguan et al. (2020) used three cations Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.9 Br 0.1 ) 3 perovskite for the surface passivation of CQDs.…”

Recent Progress of Quantum Dot‐Based Photonic Devices and Systems: A Comprehensive Review of Materials, Devices, and Applications

“…[ 197,198 ] Further great efforts have been performed to improve the performance of PbS QD‐based solar cells by adapting materials optimization, surface ligand engineering, and structure modifications, resulting in over 11% of PCE in the past decade. [ 199,200 ] In particular, Zhang et al reported PbS QD solar cells using multiple organic bulk‐heterojunction interlayer of poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b;4,5‐b′]dithiophene‐2,6‐diyl‐alt‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene‐)‐2‐carboxylate‐2‐6‐diyl)]:[6,6]‐phenyl‐C 71 ‐butyric acid methyl ester as a hole‐transporting layer, which exhibit the highest PCE of 12.02%. [ 201 ] Ligand exchange with 1,2‐ethanedithiol and the introduction of fullerene improved interfacial morphology and modulated the charge carrier injection, resulting in enhanced photovoltaic performance and scalability of devices.…”