Grain‐Boundaries‐Engineering via Laser Manufactured La‐Doped BaSnO₃ Nanocrystals with Tailored Surface States Enabling Perovskite Solar Cells with Efficiency of 23.74%

Abstract

Grain boundaries (GBs) engineering of hybrid perovskite films is of significance for accessing high performance perovskite solar cells (PSCs), owing to the abundant defect states existed therein originating from the low temperature film processing. Nanocrystals embedding at GBs has shown profound advantages in carrier dynamics modulation, while the surface defects on nanocrystals in turn lead usually to the trapping of carriers at GBs. The authors herein demonstrate the efficient GBs engineering via laser generated nanocrystals with tailored surface states for improved carriers dynamics and environmental stability of PSCs. The embedding of La doped BaSnO 3 (LBSO) nanocrystals with bare surfaces in perovskite provides an additional channel to facilitate the effective carrier extraction and reduce the carrier recombination, leading to a maximum power conversion efficiency (PCE) of 21.11% with negligible hysteresis for the mixed-cation PSCs. To clarify the influence of surface defect states of the laser generated nanocrystals on the performance of PSCs, 1H,1H-perfluorooctylamine is grafted on LBSO nanocrystals during the laser irradiation, resulting in improved champion PCE up to 21.65% and pronounced environmental stability. The universal embedding of the LBSO nanocrystals with tailored surface states in different perovskite by fabricating FAPbI 3 PSCs with a champion PCE of 23.74% is further demonstrated.

Molecular engineering of contact interfaces for high-performance perovskite solar cells

“…Devices with such coherent SnO 2 /perovskite interfaces yielded a certified PCE of 25.5% 69 . Beyond SnO 2 , various other ETLs processed at low temperature, such as BaSnO 3 (La-doped) 70 , ZnO [71][72][73] , Zn 2 SnO 4 (refs. [74][75][76] ) and Nb 2 O 5 (refs.…”

Laser Manufactured Nano‐MXenes with Tailored Halogen Terminations Enable Interfacial Ionic Stabilization of High Performance Perovskite Solar Cells

“…Following a typical anti-solvent procedure, the mixed-cations FA-based perovskite films (Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 ) were fabricated on TiO 2 /fuorine-doped tin oxide (FTO) substrates by employing the nano-Ti 3 C 2 T x colloidal solutions as the antisolvent. [32][33][34] We denote the reference perovskite as "CsFAMA" and the nano-Ti 3 C 2 T x -embedded perovskite as "CsFAMA-T (T = F, Cl, Br or I)". The top-view scanning electron microscopy (SEM) images highlight morphological differences with increasing the concentrations of nano-Ti 3 C 2 T x (Figure S14, Supporting Information).…”

“…The halogenterminated nano-MXenes were generated via pulsed laser irradiation in the green anti-solvent of ethyl acetate (EA, Figure S1a, Supporting Information), and subjected to the interfacial embedding in the perovskite film for a n-i-p planar PSC device (Figure 1a,b). [32][33][34] Owing to the well-inherited halogen feature on the surfaces of nano-MXenes, heterointerfaces between nanocrystals and perovskite were constructed through strong ionic bonding, which demonstrated both theoretical and experimental advances on highly stabilizing the hybrid perovskite, leading to unencapsulated PSCs that could maintain over 90% of their initial efficiency after 1000 h of continuous illumination under maximum power point (MPP) operating conditions, and more than 85% of their initial efficiency after 1000 h even under thermal stress of 85 °C. The constructed heterointerface, which is fundamentally different from general ionic additives, could not only impede the lattice instability from soft FA-based perovskites, but also lower the interfacial charge transfer barrier by tuning the work function of perovskite films (Figure 1c), thereby leading to highly stable PSCs with simultaneously boosted PCE up to 24.17%.…”

Recent Advances on Nanocrystals Embedding for High Performance Perovskite Solar Cells

“…In addition, there are many other NCs/QDs such as γ-graphdiyne QDs, [112] n-type goethite (FeOOH) QDs, [113] Si QDs, [36] metal organic frame (MOF) NCs, [114,115] La doped BaSnO 3 (LBSO) NCs [116] that have also been used for enhancing c) the proposed hole-transport process in perovskite with Au@CdS NCs passivation. Reproduced with permission.…”