Core/Shell Nanocrystal Tailored Carrier Dynamics in Hysteresisless Perovskite Solar Cells with ∼20% Efficiency and Long Operational Stability

Abstract

The ambient stability, hysteresis, and trap states in organo-halide perovskite solar cells (PSCs) are correlated to the influence of interlayer interfaces and grain boundaries. Astute incorporation of Cu2ZnSnS4 (CZTS) and Au/CZTS core/shell nanocrystals (NCs) can realize the goal of simultaneously achieving better performance and ambient stability of the PSCs. With optimized Au/CZTS NC size and concentration in the photoactive layer, power conversion efficiency can be increased up to 19.97 ± 0.6% with ambient air stability >800 h, as compared to 14.46 ± 1.02% for the unmodified devices. Through efficient carrier generation by CZTS and perovskite, accompanied by the plasmonic effect of Au, carrier density is sufficiently increased as validated by transient absorption spectroscopy. NCs facilitate the interfacial charge transfer by suitable band alignment and removal of recombination centers such as metallic Pb0, surface defects, or impurity sites. NC embedding also increases the perovskite grain size and assists in pinhole filling, reducing the trap state density.

Interfacial Embedding of Laser‐Manufactured Fluorinated Gold Clusters Enabling Stable Perovskite Solar Cells with Efficiency Over 24%

“…[ 39 ] Strategies of embedding metal‐based nanostructures with protective coatings into the perovskite layer have thus been developed to avoid the direct contact between metal and perovskite. [ 28,40–42 ] This work shows that the grafting of PFDT on gold enables the insulation of the contact between gold and perovskite, while differs apparently from the cases of utilizing the SPR effects of gold structures, which can be reflected from the truth that embedding of FGCs has little effect on the optical properties of the perovskite/FGCs films (Figure S25, Supporting Information). It would thus be of interests to explore the roles of FGCs on the interfacial modification of PSCs, considering that the FGCs present more molecular features due to the dramatically decreased sizes, evidenced by the disappeared SPR absorption and emerged photoluminescence.…”

Plasmonic–perovskite solar cells, light emitters, and sensors

“… 17.76–19.42 9.34 Hot electron transfer 207 Perovskite Au/Cu 2 ZnSnS 4 core/shell nanocrystals 10 N.A. 14.46–19.97 38.11 Reduction of recombination centers and increase of carrier lifetime 208 PCBM–Al electrode Al NP– 20–70 N.A. 10.54–11.74 11.39 Improvement in the active layer due to photon absorption by both scattering and plasmonic effect in addition to reduced series resistance 209 Perovskite Ag nanorods L = 200 D = 20 N.A.…”

Ambient-stable near Unity Photoluminescence Quantum Yield in Two-dimensional Tin Bromide Perovskites

“…Although the PLQY shown in Figure 2e,fwas recordedwith the 8N8-DJ powder, optoelectronic devices need large-area films where the non-radiative recombination due to the agglomerations and pin-holes are deleterious to thelight absorption and emission. 21 Three 1 cm 2 8N8-DJ films were prepared with polymethyl methacrylate (PMMA) binder where the perovskite concentrations are 250, 125 and 83 mg/mL, and these films are termed as DJ-1, DJ-2 and DJ-3, respectively. All the 8N8-DJ-PMMAfilms exhibit yellow luminescence under 365 nm UV light(Figure 3a).…”