Simultaneous Bulk and Surface Defect Passivation for Efficient Inverted Perovskite Solar Cells

Abstract

Structural defects in the bulk and on the surface of the perovskite layer serving as trap sites induce nonradiative recombination losses, limiting the performance improvement of perovskite solar cells (PSCs). Herein, we report a trometamol-induced dual passivation (TIDP) strategy to fix both bulk and surface defects of perovskites, where the trometamol molecule can simultaneously act as chemical additive and surface-modification agent. Studies show that trometamol as an additive can effectively reduce ionic defects and enhance the grain size of perovskites through Pb 2+ /−NH 2 coordination bonds and I − /−OH hydrogen bonds. As a surface-modification agent, trometamol further passivates ionic defects at the upper surface of the perovskite layer. As a result of the TIDP approach, a remarkable efficiency augmentation from 17.25% to 19.17% and an optimized thermal stability under inert conditions have been realized. These results highlight the importance of the TIDP strategy in perovskite defect management for excellent photovoltaic properties, facilitating the fabrication of highperformance PSCs.

Microwave-facilitated crystal growth of defect-passivated triple-cation metal halide perovskites toward efficient solar cells

“…The three different perovskite films except for the MWA–TOPO film commonly exhibited definite boundaries between polygon-shaped grains with clearly angled edges, which feature is observed in general for three-dimensional perovskite films. 71–74 In contrast, for MWA–TOPO, the perovskite grains were found to have round-shaped edges and multiple grains were connected or merged with obscure boundaries between them. It should be noted that the CTA, MWA–CB, and CTA–TOPO perovskites were grown without TOPO coordination or were passivated only after finishing the growth.…”

Defects in Perovskite Solar Cells and Their Passivation Strategies

“…It does not show a gap state, which is a benign grain boundary. Like other materials, perovskite materials have many suspended bonds, surface dislocations, etc., and the carrier recombination caused by surface defects is more severe than those at grain boundaries [65,66] . This was demonstrated by Sum et al., who used single‐ and two‐photon absorption selective excitation to find significant differences in the photophysical properties of the surface and bulk regions of perovskite single crystals.…”

Beyond Protocols: Understanding the Electrical Behavior of Perovskite Solar Cells by Impedance Spectroscopy

“…[80] Several studies employed TAS to show improved passivation and reduced N t values by incorporating additives into the Pbbased perovskite precursor inks. [81][82][83] Bilateral alkylamines, has shown significant impact to enhance PCEs of MAPbI 3 (18.3% to 21.7%) and Cs 0.05 FA 0.70 MA 0.25 PbI 3 (17.0-21.5%)-based PSCs. [83] Accordingly, incorporating 1,3-diaminopropane (DAP) into the perovskite ink resulted in one to two orders of magnitude lower DOS for DAP-based MAPbI 3 than for pristine MAPbI 3 , as seen by TAS measurements.…”